Prepare an experiment note about the reaction between dilute sulphuric acid and marble pieces (keep it simple and clear to get the best answer)
Answers
Explanation:
Six-mark questions are extended open response questions. These require longer answers than the structured questions. It is wise to plan your answer rather than rushing straight into it, otherwise you may stray away from the key points.
To gain full marks you need to:
support explanations using scientific knowledge and understanding
use appropriate scientific words and terms
write clearly and link ideas in a logical way
maintain a sustained line of reasoning, rather than getting lost or bogged down
Six-mark questions often use these command words:
describe - you need to give an account but no reason
explain - you must give reasons or explanations
devise - you must plan or invent a procedure using your scientific knowledge and understanding
evaluate - you must review information, including identifying strengths and weaknesses, and make a supported conclusion
Six-mark questions may be synoptic questions. These questions bring together ideas from two or more topics. For example, a question about fertilisers could include ideas about covalent substances, acids and alkalis, chemical calculations and effects on the environment.
The answers shown here give marking points as bullet points. You do not usually need to include all of them to gain six marks but you do need to write in full sentences, linking them logically and clearly.
Edexcel questions courtesy of Pearson Education Ltd.
Sample question 1 - Foundation
Question
Marble chips react with dilute hydrochloric acid to produce carbon dioxide gas.
The rate of this reaction can be changed by changing the size of the marble chips.
Describe how you could investigate what effect using smaller marble chips has on the rate of this reaction. Predict and explain the effect of using smaller marble chips on the reaction rate. [6 marks]
Reveal answer
Sample question 2 - Foundation
Question
Hydrochloric acid reacts with magnesium metal to produce hydrogen gas:
Magnesium + hydrochloric acid → magnesium chloride + hydrogen
Describe how you could use magnesium ribbon, and a solution of hydrochloric acid, to show that decreasing the concentration of the hydrochloric acid changes the rate of this reaction. [6 marks]
Reveal answer
Sample question 3 - Higher
Question
A student investigated the rate of reaction between zinc and dilute sulfuric acid:
Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)
The student carried out two experiments, using the same mass of zinc and the same sized pieces of zinc. The results are shown in the table.
Concentration of sulfuric acid
0.5 mol dm-31.5 mol dm-3
Temperature
20°C40°C
Rate of reaction
SlowFast
Evaluate these results, explaining the reasons why the rate of reaction in Experiment 2 is faster than the rate of reaction in Experiment 1.
In your answer you should refer to the frequency and energy of collisions between particles. [6 marks]
Reveal answer
Sample question 4 - Higher
Question
Reactions can occur when particles collide.
Rates of reactions can be altered by changing conditions.
Explain how the rate of reaction between a solid and a liquid is altered by reducing the size of the pieces of solid and by increasing the temperature of the liquid. [6 marks]