Hi there,
I'm going over some past papers as part of my revision for my Core Science GCSEs, but I have no clue what to do for a lot of the questions on the June 2013 Unit 2 Higher Chemistry paper; even after looking at the mark scheme I'm still totally confused. Could someone briefly explain to me what the answers are to this question and why, or tell me which area I need to revise to understand this? Thank you!
This is the questions I'm struggling with:
Sodium hydrogencarbonate is used as baking powder for making cakes. When the cake mixture is baked the sodium hydrogencarbonate decomposes.
The equation for the reaction is: 2 NaHCO3(s) --Heat--> Na2CO3(s) + H2O(g) + CO2(g)
1 (b) (i) The cake mixture rises when baked. Use the equation to suggest why. (1 mark)
1 (b) (ii) The same reaction can be reversed to produce sodium hydrogencarbonate from sodium carbonate.
Na2CO3 + H2O + CO2 ---> 2 NaHCO3
Do the reactants need to be heated? Give a reason for your answer. (1 mark)