23Medium
0/4

Chromium is extracted from chromium(III) oxide by reduction with aluminium.

a.

Explain why aluminium can be used to extract chromium from chromium(III) oxide.

[1]
b.

An equation for the reaction is:

Cr2O3+2Al→2Cr+Al2O3\text{Cr}_2\text{O}_3 + 2\text{Al} \rightarrow 2\text{Cr} + \text{Al}_2\text{O}_3Cr2​O3​+2Al→2Cr+Al2​O3​

Calculate the percentage atom economy for the reaction to produce chromium.

Relative atomic masses (ArA_rAr​):

  • Al=27\text{Al} = 27Al=27
  • Cr=52\text{Cr} = 52Cr=52

Relative formula mass (MrM_rMr​):

  • Cr2O3=152\text{Cr}_2\text{O}_3 = 152Cr2​O3​=152

Give your answer to 3 significant figures.

[3]

Yield and atom economy of chemical reactions (chemistry only) Questions

Practise AQA GCSE Chemistry Yield and atom economy of chemical reactions (chemistry only) with exam-style questions for Foundation and Higher tier. 32 questions covering Percentage yield and Atom economy, matched to the AQA GCSE Chemistry (8462) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.

PreviousNext

Yield and atom economy of chemical reactions (chemistry only) Questions

  1. GCSE
  2. /Chemistry
  3. /Yield and atom economy of chemical reactions (chemistry only)