Daily Practice
GCSE Science
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25th January 1991
- 1Energy Changes
Explain, in terms of bonds, why breaking bonds is an endothermic process.
- 2Exothermic and Endothermic Reactions
State what is meant by the activation energy of a reaction.
- 3Bond Energies, Cells and Fuel Cells
State whether forming a new chemical bond requires energy or releases energy.
- 4Rate and Extent of Chemical Change
State the four factors that can increase the rate of a chemical reaction.
- 5Rates of Reaction
A tangent drawn to a volume-time graph at 15 seconds passes through the points (5 s, 6 cm3) and (25 s, 66 cm3). Calculate the rate of reaction at 15 seconds.
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Any date always gives the same five questions, so a sheet can be set again or shared. All of January 1991, including the monthly compilation PDF.