STPM Chemistry Form 6 Notes – Terminology and Concepts: Liquid and Solid States (Part 4)

July 7, 2010

Berry Berry Easy would like to continue on the interesting topic of “Liquid and Solid States” Part 4 for STPM Form 6 Chemistry. In this part, we’ll be focusing on allotropes which are the different forms which an element exist. (The key point to bring home is “element”, which means that they are homogeneous) The concept of this is easy to grasp but students tend to confuse it with isotopes for unknown reasons. So make sure you know the differences. In short, allotropes of an element varies in the structure of the sane atom, while isotopes of an element varies on the number of neutrons of the atom. (Think of allotropes as how atoms are arranged, while isotopes are how the composition of subatomic particles in an atom varies).

STPM Form 6 – Terminology and Concepts: Liquid and Solid States (Part 4)

The concept of allotropy was proposed in 1841 by the Swedish scientist Baron Jöns Jakob Berzelius (1779-1848). The term is derived from the Greek άλλοτροπἱα (allotropia; variation, changeableness). By 1912, Ostwald proposed that the terms allotrope and allotropy be abandoned and replaced by polymorph and polymorphism but IUPAC and most chemistry texts still favour the usage of allotrope and allotropy for elements only.

Allotropy – existence of elements in two or more different forms (allotropes).

Elements with variable of coordination number or oxidation states tend to exhibit greater numbers of allotropic forms and typically more noticeable in non-metal (excluding the halogens and the noble gases) and metalloids.

Example:

i) Different molecular configuration

Oxygen – O₂ dioxygen (colourless), O₃ trioxygen / ozone (blue), O₄ tetraoxygen, O₈ octaoxygen (red)

ii) Different crystal structures in the solid

Group 14, Group 15, Group 16 of the periodic table

• Group 14: Carbon – graphite, amorphous carbon (soot/coal), diamond, fullerenes C₆₀ (buckyball), Ionsdaleite / hexagonal diamond (meteorites containing graphite strike to the Earth) and carbon nanotubes (buckytubes) is carbon with a cylindrical nanostructure.
• Group 15: Phosphorus – red phosphorus (polymeric solid), white phosphorus (crystalline solid P₄), scarlet phosphorus, violet phosphorus, black phosphorus (semiconductor) and diphosphorus P₂.
• Group 16: Sulphur – rhombic sulphur (large crystals composed of S₈ molecules), monoclinic sulphur (fine needle-like crystals), plastic (amorphous) sulphur (polymeric solid) and other ring molecules S₇ and S₁₂.

Enantiotropy – the allotropes are stable over a temperature range, with a definite transition point at which one changes into the other.

Example:

i) Tin has three allotropes / two enantiotropy:

• alpha tin is white (metallic) tin stable above 13.2 ˚C.
• beta tin is grey (nonmethallic) tin below 13.2 ˚C.
• gamma tin is rhombic tin.

ii) Iron has four allotropes / four enantiotropy:

• ferrite (alpha iron) stable below 770°C (BCC) and the iron becomes magnetic.
• beta iron stable below 912°C (BCC).
• gamma irons stable below 1394°C (FCC) crystal structure.
• delta irons stable from cooling down molten iron below 1538°C and has a (BCC) crystal structure.
• *BCC – Body-centred cubic
• *FCC – Face-centred cubic

Allotropes of Carbon

i) Graphite – used as lubricant (powder or oily suspension)

• layered lattice structure
• hexoganal for the crystal system
• density is 2.25 g cm^-3
• each carbon atom is bonded by strong covalent bonds (sp² hybridisation / trigonal planar) with three other carbon atoms to formed hexagonal ring.
• the layer are held together by weak van der Waals forces.
• graphite is soft and slippery due to weak van der Waals forces allow the layer to slide over one another.
• graphite is a moderate conductor of electricity along its layer (in the direction parallel but not perpendicular to the laver) due to a free electron (per carbon atom) which can move throughout the solid lattice. (Each carbon atom has one outer shell electron (unhybridised p electron) which is not used to form covalent bonds.)

ii) Diamond – used as abrasives (high velocity cutting tools) and ornaments (high refractive index)

• crystallises in a face-centred cubic structure.
• single giant molecule.
• density is 3.50 g cm^-3
• each carbon atom is bonded by strong covalent bonds (sp³ hybridisation / tetrahedral) with four other carbon atoms to formed three-dimensional giant structure.
• diamond has great hardness and high melting point due to the strong covalent bonds in the 3-D structure.
• diamond is a non-conductor of electricity due to all the four valence electrons of the carbon atoms are involved  with covalent bonding, therefore no free/delocalised electrons.

iii) Fullerene / Buckyball / Buckminsterfullerene – used as lubricant, semi-conductor, superconductors and catalyst

• Molecular formulae of fullerene are C₂₀ (smallest member), C₃₂, C₆₀ (most common member), C₇₀, C₇₆, C₇₈, C₈₄ and C₉₀.
• spherical molecules of 20 – 90 carbon atoms (32 sides, 12 pentagons and 20 hexagons).
• simple molecular solid.
• each carbon atom is bonded by strong covalent bonds (sp² hybridisation / trigonal planar) with three other carbon atoms. It also contains delocalised π electrons which does not exhibit “superaromaticity” that the electrons in the hexagonal rings do not delocalise over the whole molecule.
• Fullerene is a superconductor when it mixed with other metals.

Allotropes of Sulphur (different molecular arrangement)

i) alpha sulphur / rhombic sulphur (large crystals composed of S₈ molecules)

• lemon yellow colour
• shape of an octahedron.
• crystallises with the orthorhombic lattice.
• more stable at room temperature (formed in temperature below 95.6˚C).
• melting point at 113˚C.
• density is 2.07 g cm³.

ii) beta sulphur / monoclinic sulphur (fine needle-like crystals of S₈ molecules)

• deeper yellow colour
• shape of long, narrow and thin needle.
• crystallises with the monoclinic lattice.
• stable at temperature above 95.6˚C.
• melting point at 119˚C.
• density is 1.94 g cm³.

So by now you should know about allotrophy. So your diamonds are just allotropes of carbon.

Posted in: Berry Reference (Notes) | 5 Comments »

SPM Biology Form 4 Notes – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part III – Final)

July 2, 2010

Ever wondered why you need to drink isotonic drinks (100 Plus as an example) after doing sports? Okay, mainly because it tastes good as any sweetish cold drink after much exercise is appreciated. However, isotonic drinks does more than that as it replenish fluids after you lose some fluid through sports. Well, Berry Berry Teacher thinks that most of our knowledgeable Berry Readers knows about the isotonic part, but how about hypotonic and hypertonic? Hypertonic do not make you any more hyper, while hypotonic do not have anything to do with hippopotamus. So let us ride through the journey of substances across plasma membrane with Part 3 (final part) of this series.

SPM Form 4 – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part 3 – Final)

Type of Solution

1. Hypotonic
2. Isotonic
3. Hypertonic

1) Hypotonic

• Solute concentration in the external solution is lesser than solute concentration inside the cell.
• Water concentration outside the cell is higher than the water concentration inside the cell.

2) Isotonic

• Solute concentration in the external solution is equal to the solute concentration inside the cell.
• Water concentration inside and outside of the cell is the same.

3) Hypertonic

• Solute concentration in the external solution is greater than solute concentration inside the cell.
• Water concentration outside the cell is lower than the water concentration inside the cell.

Types of solutions:

Application

1. Food is soaked in a concentrated salt solution to prevent bacteria and fungus to survive.
2. Chemical fertiliser (dissolved ions) increases solute concentration (decrease water molecules) in soil. Therefore, water leaves from the cell sap of the plant which result the plant wither.

Finally, the end of the interesting substance movement over plasma membrane. Do keep note that this might be a popular essay question. Easy to answer but hard to score, so take note of the terminologies and concepts shown above.

Posted in: Berry Reference (Notes) | 1 Comment »

World Cup Predictor Mathematical Model

June 26, 2010

Berry Berry Jenius of Berry Berry Easy would like to showcase a fun (meaning: not to be taken too seriously) and non-scientific (meaning: it comes from his head) manner of predicting World Cup results (overall and individual matches). It attempts to use pseudo-scientific manner to look at the art of prediction. Better to use a proper prediction method than gut feelings in the long term. Gut feelings allows good prediction when inspired, prediction model allows more objective review for long term. The best part is you can fine-tune this model yourself to suit your own beliefs.

Berry Berry Jenius’ World Cup “Second Round Matches” Predictor Mathematical Model for World Cup 2010 in South Africa (Prediction Model Release to Public Domain before Start of Second Round Match involving Uruguay and S. Korea)

This model predicts the scores from the knock-out stage onwards using few assumptions, which are:

1. “Tayar pancit” syndrome where top performance of a team cannot be sustained for too long in a month long tournament, so teams that performed well early will be ‘penalised’ in this mathematical model. (Argentina and holland are great examples in the 2006 World Cup where they thrashed their initial opponents)
   
2. “Fresh legs” syndrome where teams that had extended matches will invariably feel tired in the next match. So teams that played extended matches (penalty/extra time) will be ‘penalised’ in the next round’s prediction. (South Korea in 2002 played a lot of extended matches until they become toothless in their match against Germany in the semifinal match)
   
3. Fear factor. Face it, European and South American teams tend to have the fear factor. So they will have a slight ‘advantage’ given to them for the entire duration of the tournament. (So far, proven with South Americans all qualifying for the next round)
4. “Momentum“. Winners tend to have winning mentality. Once you start winning, you tend to be more confident. (It took South Korea many World Cups to win their first game, and when they do, it is off to the semis) So the last game a team plays have great bearing on the form.
   

So, for the second round match 5 factors are selected to predict form of each team,and the 5 factors are:

1) Points obtained in group stages (Pts):

• If a team obtained : 9 points , they get a weighting factor of = 0.7
• If a team obtained : 5-7 points , they get a weighting factor of = 1.0
• If a team obtained : 3-4 points , they get a weighting factor of = 0.4
• Why do teams that get 9 points (maximum) get lower weighting factor? This is due to the “tayar pancit” syndrome. But when teams struggled to enter the knock-out stages, it probably mean that they are too weak.

2) Goal Difference (GD):

• If a team has a goal difference of > +5, they get a weighting factor of = 0.8
• If a team has a goal difference of 3-5, they get a weighting factor of = 1.0
• If a team has a goal difference of 1-2, they get a weighting factor of = 0.6
• If a team has a goal difference of <1, they get a weighting factor of = 0.4
• Once again, teams that peaked too early is slightly penalised with a slightly lower weighting factor. Nonetheless, weak teams with poor goal difference is still weighed down.

3) Goal Against (GA):

• If teams conceded no goals in the group stages, they will get a weighting factor of = 0.8
• If teams conceded 1-2 goals in the group stages, they will get a weighting factor of = 1.0
• If teams conceded 3-5 goals in the group stages, they will get a weighting factor of = 0.7
• If teams conceded > 6 goals in the group stages, they will get a weighting factor of = 0.5
• The numbers are chosen based on a multiple of numbers played, which is n=3. Teams that are strong defensively are given high weighting factors, but teams which have yet to let in a goal will be slightly penalised as statistically speaking, it is a matter of time before they do.

4) Continent (C):

• A team from Europe will get a weighting factor of = 1.0
• A team from South America will get a weighting factor of = 1.0
• The rest will get a weighting factor of = 0.8
• This unfair advantage given to European and South American teams is due to their ability to ‘strike fear’ into teams before they even play. Teams won’t admit it but it is true to a certain extent.
• (It is tempting to pull Europe’s weighting factor down to 0.9, considering that they are performing poorly as a continent)

5) Last group game results (LG):

• A team that won their last game is given a weighting factor of = 1.0
• A team that drew their last game is given a weighting factor of = 0.8
• A team that lost their last game is given a weighting factor of = 0.5
• Momentum is everything in a short tournament like this, provided you don’t peak too early. Slowly building momentum is better.

So, the FORMULA:

For second round predictor, the % weight for each factor are:

1. Point scored in group games (Pts): 20%
2. Goal difference (GD): 15%
3. Goal against (GA): 25%
4. Continent (C): 10%
5. Last group game results (LG): 30%

Final formula:

Form Factor: [(Pts) x 20] + [(GD) x 15] + [(GA) x 25] + [(C) x 10] + [(LG) x 30]

The form factor for each calculated teams are as follow (you may contact me for the raw data if required)

How to interprete the form factor?

When two teams meet in the second round, the team with the higher form factor will win the match. At second round, the interpretation of winning will be as follow:

• If the difference of the form factor between the two teams are:
• If difference of form factor less than 5, then win by penalty
• If difference of form factor is 5<x<10 – win in extra time
• If difference of form factor is >10, win in regular
• Every 10 predictor point advantage = 1 goal win

Second Round Prediction (Form factor in parenthesis) :

• Uruguay (95) vs S. Korea (59) – Uruguay to win by 3 goals
• USA (85) vs Ghana (62.5) – USA to win by 2 goals
• Netherlands (94) vs Slovakia (66.5) – Netherlands win by 2 goals
• Brazil (94) vs Chile (79) – Brazil to win by 1 goal
• Germany (100) vs England (94) – Germany to win in extra time
• Argentina (91) vs Mexico (65.5) – Argentina to win by 2 goals
• Paraguay (88) vs Japan (92.5) – Japan to win via penalty
• Spain (94) vs Portugal (86) – Spain to win in extra time

===================================================

Berry Berry Jenius’ World Cup Winner Predictor Mathematical Model for World Cup 2010 in South Africa

The earlier model is only valid for the second round, subsequent knock out round prediction would require a change in the model. So, the extra factors to consider are:

6) Winning Margin (WM) in regular time:

• If a team win by >1 goal , they get a weighting factor of = 0.6 (QF), 0.8 (SF), 0.9 (Final)
• If a team win by 1 goal , they get a weighting factor of = 1.0 (For all stages)
• If a team win by 0 goal , they get a weighting factor of = 0.8 (QF), 0.9 (SF), 0.95 (Final)
• where QF = quarterfinal, SF = semifinal (weighting factor changes according to stage)
• Why do weighting factor change by stage? This is due to form becoming less important as the tournament progress. (They always say, it is anybody’s game in the final, so our progressive weighting factor models this)

7) Previous Form Factor points (PFF) from the previous stage:

• The form factor of a team should be carried over but at a little over the half the level of the previous stage for the next stage. So we suggest a carry over weightage of 60%

So, the new  FORMULA for quarterfinal until the end of the tournament:

For second round predictor, the % weight for each factor are:

1. Point scored in group games (Pts): 15%
2. Goal difference (GD): 15% (Hard to predict so remove as variable)
3. Goal against (GA): 25% (Hard to predict so remove as variable)
4. Continent (C): 15%
5. Last group game results (LG): 5%
6. Winning margin (WM): 5%
7. Previous Form Factor points (PFF): 60%

Final formula:

Form Factor: [(Pts) x 15] + [(C) x 15] + [(LG) x 5] + [(WM) x 5] + [(PFF) x 60/100]

The form factor for teams in the quarterfinals as predicted by the previous model are:

How to interprete the form factor in the Quarterfinals?

When two teams meet in the quarterfinal, the team with the higher form factor will win the match. At quarterfinal, the interpretation of winning will be as follow (value halved from second round):

• If the difference of the form factor between the two teams are:
• If difference of form factor less than 2.5, then win by penalty
• If difference of form factor is 2.5<x<5 – win in extra time
• If difference of form factor is >5, win in regular
• Every 5 predictor point advantage = 1 goal win

Quarterfinal Prediction (Form factor in parenthesis) :

• Uruguay (91) vs USA (84.25) – Uruguay to win by 1 goals
• Netherlands (85.9) vs Brazil (96.4) – Brazil to win by 1 goals
• Germany (96) vs Argentina (84.1) – Germany to win by 2 goals
• Japan (89.75) vs Spain (94) – Spain to win in extra time

===================================================

As for the Semifinals prediction:

Using the same formula, the form factors are:

How to interprete the form factor in the Semifinals?

When two teams meet in the semifinal, the team with the higher form factor will win the match. At semifinal, the interpretation of winning will be as follow (value halved from second round):

• If the difference of the form factor between the two teams are:
• If difference of form factor less than 1.25, then win by penalty
• If difference of form factor is 1.25<x<2.5 – win in extra time
• If difference of form factor is >2.5, win in regular
• Every 2.5 predictor point advantage = 1 goal win

Semifinal Prediction (Form factor in parenthesis) :

• Uruguay (94.6) vs Brazil (94.84) – Brazil to win via penalty
• Germany (94.6) vs Spain (92.94) – Germany to win in extra time

===================================================

Finally, for the World Cup 2010 final match prediction:

Using the same formula, the form factors are:

How to interprete the form factor in the final?

When two teams meet in the final, the team with the higher form factor will win the match. In the final, the interpretation of winning will be as follow (value halved from second round):

• If the difference of the form factor between the two teams are:
• If difference of form factor less than 0.625, then win by penalty
• If difference of form factor is 0.625<x<1.25 – win in extra time
• If difference of form factor is >1.25, win in regular
• Every 1.25 predictor point advantage = 1 goal win

Semifinal Prediction (Form factor in parenthesis) :

• Brazil (95.154) vs Germany (96.01) – Germany to win in extra time

===================================================

So based in this model, the winner would be Germany. However, this model is best used when it is updated at every round rather than an early prediction like this. Let’s see if this prediction hold? After every round, I will also update the new data to see if the model works, because it seemed unlikely that Germany can win as its path is littered with England, Argentina, Spain and possibly Brazil in the final. A safer bet based on the draw without this model prediction is Brazil and Spain, their paths is easier.

Phenomena not looked upon (maybe in the future):

1. Average age of squad, preferably at overall age of 27-29 will be given higher weighting. (Even so, preferably strikers to be younger than midfielders, which in turn be younger than defenders)
2. Strength of previous opponents as stronger opponents invariably drain away more energy than weaker opponents.
3. Number of rest day before a match. Too long a rest will make players lethargic, while too short will hinder their recovery time.
4. Tradition. It seemed that like most sports, a certain country tend to win frequently while others do not.

Give me your feedback!

by Berry Berry Jenius (I have a more complex model in spreadsheet form on my computer)

Posted in: Berry Contributor (Contributor) | 7 Comments »

UPSR and PMR, Abolished?

June 24, 2010

Will Sijil Pelajaran Malaysia (SPM) be the only compulsory national examination under the Malaysian national school system? There are discussions about it and Berry Berry Easy would like to bring to attention this news on June 20th, 2010 to all our Berry Readers.

Ujian Penilaian Sekolah Rendah (UPSR) and Penilaian Menengah Rendah (PMR), Abolished?

The news in snippets:

General:

• Education Minister Tan Sri Muhyiddin Yassin (which is also Malaysia’s present Deputy Prime Minister) has announce the possible abolishment of the PMR and UPSR examinations.
• UPSR is the compulsory school leaving national examination for Standard 6 students in Malaysia.
• PMR is the compulsory examination taken during Form 3 to gauge a student’s level before checking their suitability for art/science stream.
• If the two are abolished, this will leave SPM as the only compulsory national-level examination for school going children in Malaysia.
• STPM is not considered compulsory as not all student undergo Form 6.

Reasons given:

• It is said that the current system is seen as too examination oriented and failed to provide a holistic education. (So removal of UPSR and PMR will reduce the examination element of the whole system)
• It is also possible that both the UPSR and PMR be retained but have its nature changed from public examination to school-based assessments.
• However, no decision will be made yet (or near future) as the public would be required to give feedback.
• It is also said that for employment/job seeking, only SPM is needed, hence only one public examination will suffice.

Possible benefits of abolishing UPSR and PMR:

• It is said that with only SPM as the sole public examination, teachers and students can care less for exams and focus on improving creativity, interactivity, sports and co-curricular activities.

Opinions so far:

• Jais Abdul Karim (President of the Federation of Peninsular Malay Students (GPMS)) believe that the abolishment will strengthen the education system and produce students who are more focused. Also mentioned tha the current system is too exam-oriented which stresses out students. This caused students to study blindly in order to pass exams without truly understand the use of it in the future. However, he said that a new method or mechanism would need to be formulated to gauge the achievement of students in event this proposal is followed through.
• Hashim Adnan (President of the National Union of the Teaching Profession (NUTP)) said that UPSR should be maintained as it has its relevance. UPSR will serve to motivate primary school students to strive hard in their studies. However, he thinks that PMR could be abolished as the exams do not serve any purpose beyond determination of streams for students entering Form 4.
• Abdul Karim Abdullah (the liaison officer for the Malaysia Education Service Ex-Officers Association (PBPPPM) said that the abolishment is appropriate to allow teachers and students to gain more time to focus on co-curiculum and sports activities.

So what’s your take on this? Aye or nay to the abolishment of the UPSR and PMR examinations?

Posted in: Berry Announcement | 4 Comments »

Berry Role Model No.4 – Dedicated Nurse – Judy Goh

June 23, 2010

Berry Berry Easy would be pleased to introduce to our Berry Readers, our Berry Role Model #4. Our Berry Role Model today is Miss Judy Goh Wen Yi, a dedicated nurse with a hidden flair for performing arts. So just how talented is our young nightingale in white in performing arts? Fashion, music, drama and dance, you name it, she can do it all. Not only she can do it all, she is also quite a proven winner in all of them, garnering awards by the dozen.

You would expect her to enter the field of entertainment based on her credentials. However, this ambitious young lass decides to nurture her performing flair alongside her passion, which is in the field of nurturing the sick to wellness. It is no coincident that her penchant for performing arts goes hand-in-hand with her current job as a nurse as both jobs require intensity and full concentration at all times. Not too mention also the unseen dedication required where a minute on stage or the operating theater is the culmination of years of hard work. Berry Berry Easy think that the commendable traits of Judy Goh would be her dedication in her role in helping sick patients back to health, where most people would not even last a day working in the hospital. We wish her all the best in Institut Kesihatan Sains dan Kajururawatan Pantai (Pantai Institute of Health Science and Nursing), Ayer Keroh, Melaka. Let us listen from our Berry Role Model.

Role Model #4 – Dedicated Nurse – Judy Goh Wen Yi

1) Who are you?

> Hello everybody, my name is Judy Goh Wen Yi, you can just call me Judy. Well, who am I? I am just an ordinary girl who is pursuing my dream . I am 20 years old this year but I don’t look like one, most probably due to my height and appearance. LOL. I have tonnes of ambition but after sorting out them in my brain for a few years (during secondary school days), finally I choose to pursue my dream job as a nurse. My hobby would include inventing some new dishes (and cooking them), singing, dancing, reading manga, applying make-up and photo taking.

2) Why did you enter the field? Who/What was/is your inspiration?

> I enter this field is because of the “cute little dress” that is wore by all the nurses in the world. (That is just a joke. Sorry, I love to joke a lot) I choose to enter this challenging field simply because I love to help people and I’ll get to learn about medical knowledge in addition to the psychological needs of a patient. It is like killing two birds with a stone. As for my inspiration, I got it from a Hong Kong drama series about a bunch of young teenagers who wanted to be nurses. They continued to pursue their dream despite facing a lot of obstacles. In the end, we see that all of them had successfully achieved their dreams in becoming nurses, but the process of  chasing their dream was what that touches me a lot. They inspire me.

3) So what do you do daily as a nurse ?

> Well, actually nurses life ain’t easy. I have a very hectic and packed college schedule. Not much holiday, as the longest I had is only one week. (Can you believe it? Believe it!) My training consists of two basic criteria: Theory and practical. For theory, we will go to college and have our classes conducted by experience tutors. As for practical,  we will be off to our assigned hospital. We call it “posting time”. During posting, we will be guided by very strict clinical instructors (CI). In order to get our assignment done, we have to perform to our very best to get their recognition in order to become a nurse. We also have this system called “cross taking”, which means that each procedure done by us will be guided by the CI (trust me cross taking is not an easy task!) We have to complete the whole procedure book so thatwe can take part in the “Malaysia Nurses Board Examination”.

4) What satisfaction do you gain from your job?

> When you work all day long, sometimes you feel tired, tensed up, angry, or even frustrated, but when a patient smile and say thanks to you, that is the best satisfaction you can ever get in a job.

5) Words of advice for our readers who wish to enter your field.

> Here is a piece of advice, if you are really interested in nursing, no matter who you are, where you are from, male or female, nursing is a tough, tough, tough work. But if this is your interest you can enjoy from it.

Judy Goh

Latin dance group 1

Latin dance group 2

Nurses taking a break

Nursing group presentation

Judy with a cactus

Posted in: Berry Role Model | 2 Comments »

STPM Chemistry Form 6 Notes – Terminology and Concepts: Liquid and Solid States (Part 3)

June 23, 2010

This is Part 3 of the series of notes on “Liquid and Solid State” from Berry Berry Easy. In the previous part, the crystal systems were discussed in tabulated form. With that knowledge in hand, it is time to look at the packing of it. It is absolutely important that you draw the following structure at least once and try to have a 3D mental image of it. This action of visualising will help you to understand the information more easily. And when you understand, you don’t have to memorise it anymore, it will come natural to you. (Nonetheless, at least for the beginning, try to memorise them. Subsequent topics will require understanding from this topic, so do not skip this topic)

STPM Form 6 – Terminology and Concepts: Liquid and Solid States (Part 3)

Four types of lattice points:

1. Lattice point at the corner of the unit cell (1/8)
2. Lattice point on the edge of the unit cell (1/4)
3. Lattice point on the face of the unit cell (1/2)
4. Lattice point in the centre of the unit cell (1)

Coordination number – the number of atoms, molecules or ions (called the nearest neighbours) that surrounds a given atom, molecule or ion in a crystal lattice.

A) Simple cubic cell

Example: Caesium chloride & Polonium

• Sphere touches six other spheres.
• Four sphere in its own layer, one sphere above the layer and one sphere below the layer.
• Coordination number = 6
• Unit cell contains in total one atom (8 corners x 1/8 = 1)

B) Body-centre cubic lattice

Example: Sodium, Barium, Potassium, Iron, Manganese, Chromium & Vanadium

• Sphere touches eight other spheres.
• Second layer are placed in the hollows between the spheres in the first layer.
• Each sphere atom is in contact with four atoms in the layer above and four atoms in the layer below.
• Coordination number = 8
• Unit cell contains in total of two lattice points per unit cell (8 corners x 1/8 + 1 = 2)

C) Close-packed structures

Example: Sodium chloride

• Unit cell contains in total of four atoms per unit cell (8 corners x 1/8) + (6 faces x 1/2)

i) Cubic close packing (ABCABCABC) / Face-centered cubic / Simple cubic close packing

Thomas Harriot (1585) first pondered the mathematics of the cannonball arrangement or cannonball stack, which has a face-centered cubic lattice.

• Sphere touches twelve other spheres.
• First layer of spheres is packed as closely and each sphere atom is in contact with six other atoms.
• Second layer of spheres is placed on top of the first layer, so that each sphere in the second layer rests on the hollows between the spheres in the first layer.
• Each sphere atom is in contact with six atoms in its own layer, three spheres (atoms) in the layer above and three spheres (atoms) in the layer below.
• Coordination number = 12

ii) Hexagonal close packing (ABABABABA)

• Sphere touches twelve other spheres.
• First layer and the second layer of spheres are packed in the same way as cubic close packing.
• (Difference = the third layer of spheres is placed on top of the first layer)
• Coordination number = 12

Stay tune to Berry Berry Easy for the next part (Part 4) in this series covering allotropy and enantiotropy.

Posted in: Berry Reference (Notes) | No Comments »

SPM Biology Form 4 Notes – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part II)

June 20, 2010

Berry Berry Easy presents Part 2 of the SPM Form 4 Biology notes for “Movement of substances across the plasma membrane“. In Part 1, the uniqueness, importance, structure and permeability of plasma membrane were discussed. This part focuses on the gist of the topic, which is on ‘transport’. Both the passive and active transport process is examined in this post. One thing for sure that Berry Readers will remember long after you leave school (yup, 100% sure) is how Osmosis works. It’s a topic which for some unknown reasons will give students headache in the beginning but after you leave school, it all make sense to you. You may ask your elder siblings if they still remember osmosis. Anyway, let the notes begin.

SPM Biology Form 4 – Terminology and Concepts: Movement of Substances Across the Plasma Membrane (Part 2)

Materials must be able to move through the plasma membrane in order for the cell cytoplasma to interact with the external environment. Therefore, the movement of soluble substances can occur in several mechanisms:

• A. Process of Passive Transport
• B. Process of Active Transport

A. Passive Transport

i) Simple Diffusion

• not selective: lipid-soluble molecules, gases and water.
• not control by cell.
• movement of the molecules from a region of higher concentration to a region of lower concentration.
• Factors affecting the rate of diffusion are temperature, size of molecules/ions, diffusion gradient, surface area and diffusion medium.
• example: diffusion of oxygen and carbon dioxide at the alveolus.

ii) Osmosis:

• only water molecules.
• not control by cell.
• movement of water from a region of higher concentration to one of lower concentration and often occurs across a semipermeable membrane.
• strong sucrose solution = less water molecule = low water potential.
• weak sucrose solution = more water molecule = high water potential.
• example: absorption of water by root hairs.

iii) Facilitated Diffusion:

• very specific: glucose, nucleic aicds, amino acids, protein and mineral ions.
• control by cell.
• transport of molecules (only certain molecules) across the outer membrane of living cell by a process of carrier protein (hydrophilic group) / channel protein (Ions: Na⁺, Ca²⁺, K⁺) within the cell membrane.
• normally take place from a region with higher concentration of molecules to a region of lower concentration.
• example: absorption of digested food in the villus.

B. Process of Active Transport

• very specific: minerals ions and amino acids.
• control by cell.
• This process needs carrier proteins and energy (due to against concentration gradient) from a region of lower concentration to a region of higher concentration).
• Cell must expend energy that derived from ATP (adenosine triphosphate)
• example: human nerve cells (sodium ions are constantly transport out of the cell) / ions intake by root hairs of a plant.

Finally, the end of this part. Stay tune for the final part (Part 3) of SPM Biology Form 4 notes on “Movement of substances across the plasma membrane“.

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Announcement : 4th JB Land Scout Campfire 2010

June 15, 2010

Behold! One of the most anticipated event of the year in the district of JB is here. Without further adieu, let Berry Berry Easy share the news of the 46th Anniversary Campfire and 11th Annual Competition with all Berry Readers. The annual event for this year will last 2 days which will be held on the 16th-17th June 2010. You can be assured that you’ll have fun with an event from 4th JB Land Scout, an organisation with 46 year of history on its cap.

4th JB Land Scout 46th Anniversary Campfire and 11th Annual Competition

Title: 46th Anniversary Campfire & 11th Annual Competition

Date: 16-17 June 2010

Venue: SMK Dato’ Jaafar, Johor Bahru

Theme: Zeal, Amity, Harmony, Steadfastness

Competitions (planned):

1. Pertandingan Kawad Kaki Berformat
2. Pertandingan Memasak (Moden)
3. Pertandingan Rekaan Banner
4. Pertandingan Halangan Komando
5. Pertandingan Persembahan / Tarian

Organised by:

• President : Chew Shu Ren
• Secretary : Ronald Ang Yu Chye
• Treasurer : Benedict Tan Wen Liang
• Quarter Master : Cheng Farn Liang
• AJK : Lim Zhi Yang
  Lee Wee Han
• All members of the 4th JB Land Scout Troop

Why you should attend the campfire/competition (in Berry Berry Easy’s Opinion):

• To make lifelong friendship with people from other schools
• To spend your holiday in a more meaningful manner
• To gauge your strengths through competitive and healthy competition
• To have endless fun through the events organised
• To be part of an event you’ll be talking about many years after you leave school

So, what are you waiting for? Drop by, register and participate for the event.

(More details to follow. These are just preliminary information)

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