Daily Practice

GCSE Science

30th October 1991

5 questions · GCSE · 584 questions in this band

1
Concentration, Yield and Atom Economy
Give the formula for atom economy.
2
Chemical Changes
Explain why aluminium cannot be extracted from aluminium oxide by heating with carbon.
3
Reactivity, Acids and Salts
Why is aluminium extracted by electrolysis rather than by reduction with carbon?
4
Electrolysis
Explain why solid sodium chloride does not conduct electricity, but molten sodium chloride does.
5
Energy Changes
A reaction profile shows the reactants at 150 kJ and the peak (activation energy point) at 195 kJ. Calculate the activation energy.

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