Simple recall questions are usually worth one mark. They often have command words like 'Give...', 'State...', 'Name..' or 'Identify...'. Some questions may ask you to state two things, rather than just one, and will be worth two marks.
Structured questions, with command words such as 'Describe...' or 'Explain...', will be worth two or more marks:
More complex structured questions will be worth three or four marks. They include questions with complex descriptions and explanations, questions in which you need to compare and contrast two different things, or calculations with several stages.
The mark schemes given here may show answers as bullet points. This is to show clearly how a mark can be obtained. However, it is important that your answer is written in a logical manner, the points are linked to each other, and are relevant to the question.
Edexcel questions courtesy of Pearson Education Ltd.
Zinc can be extracted from its ore by electrolysis or by heating the ore with carbon.
Give a reason why heating the ore with carbon is actually used. [1 mark]
Heating with carbon is used as it is cheaper than using electrolysis. 
The table gives information about aluminium and tin.
|Metal||Metal cost of 1 kg||Amount in Earth's crust|
Give two reasons why it could be more important to recycle tin than to recycle aluminium. Use the information in the table. [2 marks]
Iron is extracted from its ore by heating with carbon.
Aluminium is extracted from its ore using a different method.
a) Give the name of the method used to extract aluminium. [1 mark]
b) Explain why aluminium is extracted by a different method rather than heating the ore with carbon. [2 marks]
a) Electrolysis 
Iron is extracted from iron oxide, Fe2O3.
In the extraction process, the iron oxide is heated with carbon to form iron and carbon dioxide.
Write the balanced equation for this reaction. [3 marks]