Week 1
"Compound- 2 or more elements chemically combined together."
"Mixture- 2 or more elements not chemically combined together."
We were introduced to compounds and mixtures before the holiday starts. We also learnt about word equations and had to memorise the elements that made up some compounds such as water, carbon dioxide gas etc. But how to form a compound? See the experiment below. In this experiment we burnt a magnesium ribbon over a Bunsen burner.
The word equation for this experiment is "magnesium + oxygen -> magnesium oxide."
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| magnesium oxide |
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| Magnesium Oxide |
As inferred, the forming of magnesium oxide involves chemical means, hence, it is a compound.
Mixtures, on the other hand, can be separated by several techniques, mainly filtration, evaporation to dryness, distillation, magnetic attraction and the separating funnel. We would be learning more after the holidays.
Week 6
We were given some exercises to do after the holidays to refresh our memories.
I got only 2/3 of the questions correct, and I realised that I had forgotten some key points. I also found out that alloys, which comprises two metals, are also mixtures!
Week 7
Mixtures (impure)
- Solutions
- Suspensions
- Dilute solution (too little)
- Concentrated solution (ok)
- Saturated solution (maximum)
- Suspension (too much)
Suspensions is formed when the solute is insoluble (cannot be dissolved) in the solvent or the solute added is too much.
We did an experiment involving this.
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| Salt |
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Baking Soda
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- Filtration- Filter suspension
- Evaporation to dryness- Obtain solute from residue
- Distillation- Obtain solvent from solution
- Magnetic attraction- Obtain magnetic materials from non-magnetic ones
- Separating funnel- Separate two immiscible liquid
Sugar+heat<--- See video embedded here
Partially heated sugar forms caramel. So, to obtain sugar from a sugar solution, Technique no. 2 cannot be used! We have to use crystallisation instead.
I actually carried out the crystallisation experiment at home. Here are the pictures:
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| Boiling |
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| Saturated |
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| Post-Boiling |
The simplest type of chromatography is paper chromatography. As it is difficult to explain its uses, we did an experiment instead. In the experiment, we dipped the black ink spot into ethanol and water mixture. The black ink spot actually expanded into several ink spot, mainly blue, pink and green.
Week 12
The next topic was on cells, tissues and organs. Our first lesson on cells was an experiment involving plant and animal cells.
We examined onion (plant) and cheek (animal) cells under a microscope. But, to my dismay, I could only see big, bold, purple dots. As for the cheek cell, I could not see anything at all.
Ms Chia then played a video for us to watch and take down notes.
The cell topic was quite easy as it was in the syllabus during Primary school. Personally, I was not too interested in biology and was not good at it (interests and results correspond, don't they?). Hence, I often mixed up parts of a cell and with their functions. I visited this website "Cells Alive!"to find out more about cells. I also visited Ms Chia's Wiki to clarify some doubts.
Week 14
Diffusion is the net movement of molecules moving from a region of higher concentration to that of lower concentration. It does not require any energy taken in or given out.
Osmosis is a special type of diffusion; it involves water molecules flowing from a region of higher concentration to that of lower concentration. My classmate, Nicholas, once told me that by sprinkling salt on slugs, the slugs would die. I was very curious about why salt could kill a slug. Hence, I searched the web for the Answer: Osmosis.
Week 15
For the Term 3 test, I studied very hard as they were many topics to be covered. But unfortunately, I got a B3, missing A1 by only 3 marks (before conversion to 100%). I could have gotten an A2 if not for my careless mistakes (had used "=" instead of "->" for chemistry equation and put the name of the group instead of group no. which cost me 1 mark each). I was overconfident with my previous term results and did not check my work. I will study even harder for EOY and not repeat the same mistakes.
Week 16
Before the holidays, we learnt about photosynthesis and respiration. We even did an experiment on it. We boiled a leaf and soaked it in alcohol to get rid of its chlorophyll. But, we accidentally over-boiled it and our leaf was in shreds. Well, I guess mistakes happen. We revised what we learnt in Primary school, and to make sure we had all the concepts correct.
Week 12
The next topic was on cells, tissues and organs. Our first lesson on cells was an experiment involving plant and animal cells.We examined onion (plant) and cheek (animal) cells under a microscope. But, to my dismay, I could only see big, bold, purple dots. As for the cheek cell, I could not see anything at all.
Ms Chia then played a video for us to watch and take down notes.
The cell topic was quite easy as it was in the syllabus during Primary school. Personally, I was not too interested in biology and was not good at it (interests and results correspond, don't they?). Hence, I often mixed up parts of a cell and with their functions. I visited this website "Cells Alive!"to find out more about cells. I also visited Ms Chia's Wiki to clarify some doubts.
Week 14
Diffusion is the net movement of molecules moving from a region of higher concentration to that of lower concentration. It does not require any energy taken in or given out.
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| Diffusion |
Week 15
For the Term 3 test, I studied very hard as they were many topics to be covered. But unfortunately, I got a B3, missing A1 by only 3 marks (before conversion to 100%). I could have gotten an A2 if not for my careless mistakes (had used "=" instead of "->" for chemistry equation and put the name of the group instead of group no. which cost me 1 mark each). I was overconfident with my previous term results and did not check my work. I will study even harder for EOY and not repeat the same mistakes.
Week 16
Before the holidays, we learnt about photosynthesis and respiration. We even did an experiment on it. We boiled a leaf and soaked it in alcohol to get rid of its chlorophyll. But, we accidentally over-boiled it and our leaf was in shreds. Well, I guess mistakes happen. We revised what we learnt in Primary school, and to make sure we had all the concepts correct.
