Merry Christmas & Happy New Year guys.
I'm currently watching these and think you might enjoy them. Not going to lie, they're aimed at kids a bit younger than you, but enjoy them, show them to your younger brothers and sisters.
http://www.bbc.co.uk/programmes/b00pmbqq
Wednesday, 30 December 2015
Monday, 30 November 2015
Happy birthday Miss Cooney!
Happy birthday to you!
It's scientifically proven that people who have more birthdays live longer!
From...
It's scientifically proven that people who have more birthdays live longer!
From...
Monday, 16 November 2015
Rates of reaction
What is a reaction?
A reaction happens when reactants turn into products. There are many factors that affect the speed at which this happens.
Collision Theory
Reactions only take place when the particles of the reactants come together with the right energy and orientation. The smallest amount of energy needed for a reaction to happen is called the activation energy. Reactions are more likely to happen if we increase the chance of reacting particles colliding with each other or if we increase the energy that the particles have when they collide.
Temperature
When we heat a substance, energy is transferred to its particles. This means the particles move faster, if they move faster then they collide more often. Simple.
Particles that move quicker have more energy, this means that a higher proportion of the particles have energy greater than the activation energy.
Catalysts
Catalysts allow reactions to happen at a lower activation energy. This means that more particles will have this minimum energy and reactions happen faster.
Surface area
Increasing the surface area of a substance means that there are more particles available for a reaction to take place - this means collisions are much more frequent.
Concentration
Increasing the concentration of a substance increases the rate of reaction - this is because you have more particles in a given area for collisions to happen. If you have twice the concentration then you have twice the number of particles. This would double the reaction rate - or form twice the product.
A reaction happens when reactants turn into products. There are many factors that affect the speed at which this happens.
Collision Theory
Reactions only take place when the particles of the reactants come together with the right energy and orientation. The smallest amount of energy needed for a reaction to happen is called the activation energy. Reactions are more likely to happen if we increase the chance of reacting particles colliding with each other or if we increase the energy that the particles have when they collide.
Temperature
When we heat a substance, energy is transferred to its particles. This means the particles move faster, if they move faster then they collide more often. Simple.
Particles that move quicker have more energy, this means that a higher proportion of the particles have energy greater than the activation energy.
Catalysts
Catalysts allow reactions to happen at a lower activation energy. This means that more particles will have this minimum energy and reactions happen faster.
Surface area
Increasing the surface area of a substance means that there are more particles available for a reaction to take place - this means collisions are much more frequent.
Concentration
Increasing the concentration of a substance increases the rate of reaction - this is because you have more particles in a given area for collisions to happen. If you have twice the concentration then you have twice the number of particles. This would double the reaction rate - or form twice the product.
Sunday, 18 October 2015
ISA Skills - Section 1 Paper
Dear Year 11,
Now is the time to start thinking about your ISA.
Let's go through a section one paper.
Question one
Write down your hypothesis.
Explain why you made this hypothesis. [3 marks]
This one is simple.
A hypothesis is a general statement which can be tested.
Your hypothesis needs to link your independent and dependent variable together.
As independent variable increases/decreases dependent variable will increase/decrease.
As to why you made this hypothesis, you are basically explaining your prediction based on some scientific research you have just conducted.
When I was doing some research I found out that insert statement relating to your experiment. This means that/this is because... now give a scientific reason which explains the effect of the independent variable on the dependent variable.
For example, if your ISA is on enzymes then you could say "As the temperature of the amylase increases, the rate at which the starch is broken down also increases".
When I was doing some research I found out that molecules at a higher temperature have more kinetic energy. This means that the molecules are moving faster, so the enzyme molecules are more likely to collide into the starch molecules with enough energy to catalyse the reaction. However, if the temperature rises too high, then the shape of the enzyme will change and the reaction will no longer work.
Question 2
Think about the research that you did to find how to test your hypothesis. Identify two sources that you used for your research.
Which of these sources was the more useful? Why was this source better than the other source?
[3 marks]
This is the same standard question on core, additional and further additional ISAs.
The structure of the answer is always the same:
1. Give your two sources - full website addresses and/or book titles with page numbers and name of author.
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/proteins/proteinsrev3.shtml
This will get you the mark, whereas the link below is not accessible by an examiner so wouldn't
School CRL - Science folders - KS4 x WRONG!!
2. Comment on the usefulness of both sources.
Source A was good because it had a simple equipment list and also a risk assessment. Source B was very good because it had a detailed risk assessment and an easy to follow step-by-step method.
3. Now compare them.
Because of this, overall Source B was better than source A because it had the additional detail.
Question 3
In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
From the research you have done, describe in detail how you are going to do your investigation.
You should include:
• the equipment you plan to use
• how you will use the equipment
• the measurements you are going to make
• how you will make the investigation a fair test.
• a risk assessment
[9 marks]
It is so tempting for students to write a wall of text in paragraphs because you're told you'll be marked on QWC. DON'T DO THIS! Who writes a method or a recipe this way?! it is a lot easier for your teacher to mark it and give you FULL marks if you lay it out in an easy to follow style. Use sub-heading to help you.
Equipment
List all equipment needed in a bullet pointed list.
If you haven't listed it, imagine that you wouldn't be given it.
If you need to measure temperature, then ask for a thermometer - you can't do that part of your investigation without it!
Method
This must be written as a step-by-step list.
1. Do this.
2. Do the next thing.
3. The third thing to be done is....
Variables
List your variables and how you will measure/monitor them. This is vital for the 7-9 marks.
You should aim for at least three control variables.
Independent variable - temperature, measured using a thermometer in degrees centigrade.
Dependent variable - rate of reaction, measured by timing how long the blue-black colour of the iodine starch reaction takes to disappear.
Control variables - Concentration of amylase, a 0.5M concentration will be used each time. Volume of starch solution, a 10ml volume will be used each time and measured using a measuring cylinder. Volume of iodine used, a 3ml volume will be used each time measuring using a dropping pipette.
Risk Assessment
This can be drawn as your Hazard/Risk/Precaution table.
Hazard - this should be an object which could cause harm in certain situations.
Risk - this is what could go wrong with the hazard and how likely this is to happen.
Precaution - this is what step(s) you will take to ensure the risk is minimised.
A hazard is the amylase solution, if spilled the risk of slippage is medium. To avoid this, I will take care when pouring the solution and clean up all spills immediately.
Question 4
This question is difficult to predict and could be about a range of different things to do with your investigation. Common past topics include:
Now is the time to start thinking about your ISA.
Let's go through a section one paper.
Question one
Write down your hypothesis.
Explain why you made this hypothesis. [3 marks]
This one is simple.
A hypothesis is a general statement which can be tested.
Your hypothesis needs to link your independent and dependent variable together.
As independent variable increases/decreases dependent variable will increase/decrease.
As to why you made this hypothesis, you are basically explaining your prediction based on some scientific research you have just conducted.
When I was doing some research I found out that insert statement relating to your experiment. This means that/this is because... now give a scientific reason which explains the effect of the independent variable on the dependent variable.
For example, if your ISA is on enzymes then you could say "As the temperature of the amylase increases, the rate at which the starch is broken down also increases".
When I was doing some research I found out that molecules at a higher temperature have more kinetic energy. This means that the molecules are moving faster, so the enzyme molecules are more likely to collide into the starch molecules with enough energy to catalyse the reaction. However, if the temperature rises too high, then the shape of the enzyme will change and the reaction will no longer work.
Question 2
Think about the research that you did to find how to test your hypothesis. Identify two sources that you used for your research.
Which of these sources was the more useful? Why was this source better than the other source?
[3 marks]
This is the same standard question on core, additional and further additional ISAs.
The structure of the answer is always the same:
1. Give your two sources - full website addresses and/or book titles with page numbers and name of author.
http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/proteins/proteinsrev3.shtml
This will get you the mark, whereas the link below is not accessible by an examiner so wouldn't
School CRL - Science folders - KS4 x WRONG!!
2. Comment on the usefulness of both sources.
Source A was good because it had a simple equipment list and also a risk assessment. Source B was very good because it had a detailed risk assessment and an easy to follow step-by-step method.
3. Now compare them.
Because of this, overall Source B was better than source A because it had the additional detail.
Question 3
In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.
From the research you have done, describe in detail how you are going to do your investigation.
You should include:
• the equipment you plan to use
• how you will use the equipment
• the measurements you are going to make
• how you will make the investigation a fair test.
• a risk assessment
[9 marks]
It is so tempting for students to write a wall of text in paragraphs because you're told you'll be marked on QWC. DON'T DO THIS! Who writes a method or a recipe this way?! it is a lot easier for your teacher to mark it and give you FULL marks if you lay it out in an easy to follow style. Use sub-heading to help you.
Equipment
List all equipment needed in a bullet pointed list.
If you haven't listed it, imagine that you wouldn't be given it.
If you need to measure temperature, then ask for a thermometer - you can't do that part of your investigation without it!
- Thermometer 1 oC resolution
- 0.5M amylase solution
- 10ml measuring cylinder
- ..etc
Method
This must be written as a step-by-step list.
1. Do this.
2. Do the next thing.
3. The third thing to be done is....
Variables
List your variables and how you will measure/monitor them. This is vital for the 7-9 marks.
You should aim for at least three control variables.
Independent variable - temperature, measured using a thermometer in degrees centigrade.
Dependent variable - rate of reaction, measured by timing how long the blue-black colour of the iodine starch reaction takes to disappear.
Control variables - Concentration of amylase, a 0.5M concentration will be used each time. Volume of starch solution, a 10ml volume will be used each time and measured using a measuring cylinder. Volume of iodine used, a 3ml volume will be used each time measuring using a dropping pipette.
Risk Assessment
This can be drawn as your Hazard/Risk/Precaution table.
Hazard - this should be an object which could cause harm in certain situations.
Risk - this is what could go wrong with the hazard and how likely this is to happen.
Precaution - this is what step(s) you will take to ensure the risk is minimised.
A hazard is the amylase solution, if spilled the risk of slippage is medium. To avoid this, I will take care when pouring the solution and clean up all spills immediately.
Question 4
This question is difficult to predict and could be about a range of different things to do with your investigation. Common past topics include:
- An alternative method you didn't use.
- A range you have chosen for your independent variable.
- Preliminary investigations.
- A resolution you have chosen for a piece of measuring equipment (usually section 2 though).
Question 5
The easiest two marks on the paper - draw a blank results table.
[2 marks]
You need two headings with units, that's it. Doesn't even matter which way round they go! As long as they match your hypothesis and your method.
Something for your to do!
I have written a method for the 9 mark question. Mark it out of 9 with feedback below.
Provide me with points on at least 3 strengths and 2 areas for improvement:
"Increasing the concentration of enzyme will make it work faster."
1. Take a beaker and 6 test tubes, place the test tubes in the beaker.
2. Add 3cm3 of full fat milk to each tube, this keeps the experiment
constant. The milk is the substrate.
3. Add 2cm3 Sodium Carbonate to each tube, this keeps the
experiment constant and makes the solution alkaline.
4. Add 5 drops of phenolphthalein indicator to each tube, again this
keeps the experiment constant, it will make the solution pink. If
all the tubes have the same volumes of milk, sodium carbonate
and indicator, they should all be of the same colour.
5. Fill the beaker full of 40°C water;
6. Take a stopwatch. Add 1cm3 of water first to test tube 1 then
start the timer. After a minute add 1% enzyme to test tube 2.
After 2 minutes add 2% enzyme to the 3rd test tube and so on.
7. I will do this experiment twice………………………………..
8. I am going to measure how long it takes for the pink solution to
turn white, and record the data in a table
9. On the website it said “This chemical may cause irritation if you
get it into your eyes or breathe it in.”
10. I must make sure I don’t spill it on me and I am going to wear
safety goggles. If I get any on my skin I must wash it off with
water straight away.
Marking Criteria:
Monday, 12 October 2015
Chemistry - Rocks and Building materials C1.2
Key points to remember:
- Limestone is mainly made of calcium carbonate (CaCO3) - this means it will contain other impurities.
- It is a sedimentary rock formed from the remains of tiny animals and plants that lived millions of years ago.
- Its main use is as a building material
- Powdered limestone can be heated with clay to make cement.
- Cement mixed with water, sand and crushed rock, produces concrete in a slow chemical reaction.
- Heating limestone at a very high temperature causes a thermal decomposition reaction to occur
- calcium carbonate --> calcium oxide + carbon dioxide
- Buildings made from calcium carbonate are badly damaged by acid rain.
- calcium carbonate + acid rain --> calcium salt + water + carbon dioxide
The Limestone Reaction Cycle
1. If we start with calcium carbonate and heat it strongly we end up with calcium oxide
2. If we add a small amount of water to the calcium oxide we get calcium hydroxide.
3. If we then add more water and filter we get lime water or calcium hydroxide solution.
4. We then add carbon dioxide to lime water and we get back to our calcium carbonate.
Common mistakes that students make in this unit are:
- They not take into account the social, moral and ethical issues associated with quarrying limestone
- They forget that limestone is a carbonate and cannot apply knowledge of the reaction cycle to a different carbonate.
Try the question below:
Thursday, 8 October 2015
Chemistry - Fractional Distillation
Shout out to Abdullah
Fractional distillation is a common topic in C1. When it comes up it is often worth 10/12 marks - 20% of the exam paper. It is important to understand the physical processes that are occurring during fractional distillation.
Describe and Explain the process of Fractional Distillation (6 marks). Not QWC.
The first thing we need to do is look at the command words given to us in the question. Describe and Explain.
Describe: recall facts e.g. what does it look like? what happens? Step-by-step.
Explain: give a clear scientific reason - link it to the question.
Then we need to look at what the question is asking us about. Fractional Distillation.
So we now know that we need to recall facts about fractional distillation and say what happens step by step, then we need to give a scientific reason that this happens.
Description of fractional distillation.
Fractional distillation is a common topic in C1. When it comes up it is often worth 10/12 marks - 20% of the exam paper. It is important to understand the physical processes that are occurring during fractional distillation.
Describe and Explain the process of Fractional Distillation (6 marks). Not QWC.
The first thing we need to do is look at the command words given to us in the question. Describe and Explain.
Describe: recall facts e.g. what does it look like? what happens? Step-by-step.
Explain: give a clear scientific reason - link it to the question.
Then we need to look at what the question is asking us about. Fractional Distillation.
So we now know that we need to recall facts about fractional distillation and say what happens step by step, then we need to give a scientific reason that this happens.
Description of fractional distillation.
- During fractional distillation a mixture of crude oil is heated to 350 degrees Celsius at the bottom of the fractionating column.
- The column is hotter at the bottom than at the top
- The crude oil starts to vaporise
- These vapors rise up the fractionating column
- The vapors condense at different fractions so they separate
- The condensed fractions are collected.
Explanation of fractional distillation
The different compounds in the mixture have different boiling points so they vaporise at different temperatures, these vapors then rise up the fractionating column. The vapors then condense at different temperatures depending on their boiling point and their size.
Now we have our description and explanation we can put these together and answer the question.
During fractional distillation a mixture of crude oil is placed into the bottom of a fractionating column where it is heated to 350 degrees celsius. Smaller hydrocarbons in this mixture start to evaporate and will rise up the fractionating column. The smaller the hydrocarbon the higher up it will rise as it has a lower boiling point. The vapors will all condense at different temperatures and they are separated and collected.
In the comments I would like you to mark this answer (4 marks are awarded for describing and two for explaining), I would like you to point out which parts of the above answer are descriptive and which are explanatory and then I would like you to give a six mark answer for this question.
Sunday, 4 October 2015
Happy Birthday Mr Shah
Happy birthday to you
Happy birthday to you
Happy birthday dear Mr Shaaaaaaaah
Happy birthday to you
From.....
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