AQA GCSE General Science 5th JuneWatch
Post any questions you remember and I'll compile the answers into an unofficial mark scheme!
- Thalidomide can now be used to treat leprosy.
- A pathogen is a micro-organism that causes disease.
- Drugs are trialed to check dosage or check if they work.
- Drugs are addictive because, as they change chemical processes, the patient suffers withdrawl symptoms.
- The process that plants and algae carry out is photosynthesis.
- The carbon in the atmosphere is changing, as there is more being added to the atmosphere than there is being removed.
- Control variables were lawn size, volume of weed killer etc.
- The 0 result acts as a control for comparison.
- The percentage change in goldfinches was 60.3.
- Skin receptors detect heat, pressure and pain.
- Oestrogen is produced in the ovary & thickens the womb lining.
- The part of the cell that controls the enzyme reaction is the nucleus.
- Optimum temperature for industrial bacteria growth is 40°c.
- Effectors are the muscles (contracts) and the glands (secretes hormones).
- A gene is a section of DNA which controls characteristics.
- Total of Carbon released from respiration is 140 billion tonnes.
- The minimum time for drug development is 6 years.
- The range of people in the drug test is 50 to 6000 or 5950.
- Bladder Wraks grew faster as the air bladders allowed them to float, compete for light & photosynthesize.
What is the atomic number? Number of protons (1 Mark)
What is the mass number? Number of protons plus neutrons (1 Mark)
Why doesn't an atom have any charge? This is because they have the same number of positively charged protons in the nucleus, as the number of negatively charged electrons in their shells. (2 Marks)
The periodic tables groups? This is because they have the same number of electrons in their outermost shell (7 electrons in their outermost shell) and thus have similar chemical properties. (2 Marks)
Tick the correct box: S (Sulphur) (1 Mark)
Particles that include non-metal and metal: Ions (1 Mark)
Particles that include two non-metals: Molecules (1 Mark)
Limestone is calcium… carbonate (1 Mark)
Calcium oxide is produced through thermal… decomposition (1 Mark)
Calcium hydroxide is created by adding… water (1 Mark)
How can limestone be used to neutralize acids? It’s an alkali. (1 Mark)
Line of best fit (In red) (2 Marks)
How could the accuracy be improved?
By repeating the step shown in figure 2, calculating an average (discarding anomalies). OR Decreasing the intervals between results being taken. (2 Marks)
Estimate the force needed for 0g from the graph? 45 (This value will slightly vary) (2 Marks)
Why isn't his prediction about the trend correct? Because after 400 grams, the force needed begins to decrease as for 700 grams, the force needed is 100 newtons. (3 Marks)
Why are there so many theories? Lack of reliable evidence from the time. Also some evidence conflicts causing many theories. (1 Mark)
Change in the earth's surface and atmosphere: In the early atmosphere billions of years ago, it is thought that, due to intense volcanic activity, in the Earth’s atmosphere, there was a lot of carbon dioxide, water vapour and small proportions of methane and ammonia. However, over this changed. As the Earth’s atmosphere began to cool down, the water vapour in the air condensed to form oceans. This caused a lot of the carbon dioxide within the air to be dissolved into the water and thus removing a lot of it from the atmosphere. Moreover, a lot of the carbon within the water, overtime, became carbonate. This then formed parts of the shells and skeletons of the sea creatures within the ocean. When they died, they became sedimentary rocks, thus locking up a lot of the carbon. Furthermore, when algae and plants came into existence, they were able to undergo a process called photosynthesis. Photosynthesis is a process which encompasses Carbon Dioxide converting into Oxygen. This meant that, as the years went by, there was a reduction in amount of Carbon Dioxide and increase amounts of oxygen. As a result of all of this, the atmosphere is around 80% nitrogen and 20% oxygen, however there are small proportions of carbon dioxide, water vapour and noble gases. This number is changing. This because, from the exponential rapid population increase of the human population, fossil fuels – made up of carbon and dead, fossilised plants and animals – are being used to generate electricity. This means that, at the moment, the increase rate in these being burnt has resulting in an increase in Carbon Dioxide in our atmosphere. (6 Marks)
Why was stage 2 (separation) necessary? This is so that the ore is concentrated meaning that the metal produced will be purified, ridding of any impurities found within the ore. This is why you are separating so that when the metal is extracted, no impurities will be within. (2 Marks)
Why isn’t cast Iron suitable for pylons? Too brittle, easily brakes. (1 Mark)
Describe the process shown in the diagram (Cast Iron + Oxygen --> Waste gases + Steel) Cast iron is heated in a furnace in the presence of oxygen, so that it can form an alloy with carbon to produce steel. At the high temperature at the bottom of the furnace, carbon dioxide reacts with carbon to produce carbon monoxide. It is the carbon monoxide which is the main reducing agent in this part of the furnace. In the hotter parts of the furnace, the carbon itself also acts as a reducing agent. As the cast iron is heated, the carbon and, in some parts of the furnace, the carbon monoxide react with the cast iron entering the furnace to form the alloy steel. The temperature of the furnace is hot enough to melt the steel which trickles down to the bottom where it can be tapped off. (2 Marks)
Why is aluminium more suitable for pylons compared to copper? Its less
dense, therefore lighter. (1 Mark)
From the periodic table, how can we tell that copper is a transition metal?
Aluminium is found in group three meaning it has only 3 electrons in its outermost shell. Moreover as it is in this certain group, its charges of its ions can have only one set charge. However copper is not in any numbered group but in group which is between group 2 and 3, meaning that copper can have ions with different charges and thus is a transition metal. Furthermore, within the group that it in, it is surrounded by only transition metals. (2 Marks)
How is copper extracted from Copper salts using iron?
As iron is more reactive than copper, the scrap iron can displace the copper within the copper ions so that the copper produced will be pure./Removes the impurities (2 Marks)
How are fractions of oil separated? Crude oil enters a fractionating column is hot vapour which has been heated up to around 350°C. At the top of the column it is cooler and towards the bottom it is hotter. As the hydrocarbons within the crude oil all have different boiling points, the long chain hydrocarbons with the highest boiling points will be separating out the bottom of the column, the rest of the hydrocarbons rise up through the column as a hot vapour. When the hydrocarbons reach a certain temperature which is their boiling points, the gases will condense into their liquid forms and be separated into fractions. (4 Marks)
Suspension of limestone: Sulfur dioxide and Nitrogen oxide are slightly acidic, they therefore react with Calcium Carbonate to produce a salt, water and carbon dioxide. This reduces the amount of Sulfur dioxide and Nitrogen oxide in the air, thus reducing levels of acid rain. (3 marks)
C2H4 (1 Mark)
Draw the hydrocarbon (3 Marks)
How to smart polymers differ from normal polymers?
The change their properties when there are changes in the environment i.e. they react to heat and temperature. (1 Mark)
6. Vegetable Oils
Why are vegetable oils useful for both fuels and in food? They contain a lot of energy. (1 Mark)
Why are vegetable oils more useful compared to water in cooking?
They have a high boiling point, thus they provide a lot of energy. (2 Marks)
State two process used in extracting vegetable oil from seeds?
Plant Material is crushed and the oil is removed by pressing or distillation; water and other impurities are removed. (2 Marks)
How to emulsifiers work?
Its head is hydrophilic and the tail is hydrophobic the emulsifier is negative charge.The ‘tail’ dissolves in the oil making tiny droplets. The surface of each oil droplet is charged by the ‘heads’ sticking out into the water. As the head is negatively charged, the like charges repel each other. This keeps them spread throughout the water, stopping the oil and water separating into two layers. (4 Marks)
Credit to @Harrywigman for helping
- Battery stores chemical energy. 
- The motor convert electrical energy into kinetic energy. 
- Some energy is wasted as sound (Not heat). 
- Work out the sankey diagram efficiency: 37.5% 
- 6 Mark question: Talk about each type of energy saving, what they do and their payback time. 
- What is a U value? Measurement of how effective a material is as an insulator. 
- What will happen to the U value with more insulation? Decreases 
- Why can’t it be a bar graph? Because the data is continuous. 
- 8 / 10 = 0.8 (10%) so 8 - 7.2 = 0.8 meaning it is 10% 
- The temperature outside must be constant so not to change the results and affect the outcome. 
- 10% Won’t always be correct as people will have different rates of energy transfer. 
- Circle the resolution: 0.5 
- 20.5°C 
- Type of wave? Microwaves 
- Draw the normal 
- Properties of waves in the electromagnetic spectrum: 
- Draw the reflection 
- Wave which gives of most heat? Infra red 
- Why isn't the solar power always working to full efficiency? Sun ain’t always shining. So electricity won’t be generated. 
- [Renewable vs Nonrenewable question] All the renewable energy sources depend on the weather being appropriate for them to produce energy whereas the non-renewable energy sources do not and as a result the renewable energy sources have a lower capacity factor because of the intermittent nature of the weather such that the conditions are not necessarily conducive to the production of electricity when, for example, there is no wind. 
- The Specific heat capacity must be high in order to retain the thermal energy and so that more thermal energy can be stored. 
- 16 hours 
- What is the effect on the ball? Doppler effect. 
- Wave comparison: Wavelength decreases / same speed / frequency increases 
- Specific heat capacity: 4200 J/kg°C 
- [Conduction question] The can-chiller cools the surroundings of the can. This causes a temperature gradient between the inside of the can and the outside. The result of this temperature gradient is that thermal energy moves out of the can by conduction. The electrons in the metal diffuse through the metal and collide with other electrons to transfer the kinetic energy and the particles vibrate with a similar intention, causing the thermal energy to be transferred from the inside of the can to the outside, thus cooling it down. 
- Convection? Heats up, less dense, rises, cools down, more dense, falls back down.