# A level chemistry

#1
15.0g of SiO2 and 8.5g of carbon are heated together to form silicon carbide and carbon monoxide.SiO2 3C = SiC 2CO. Can somebody tell me why silicon dioxide is an excess reactant in this reaction
Last edited by yhh65; 3 months ago
0
3 months ago
#2
using the respective masses and Mr, can you work out the moles of SiO2 and C present?
0
#3
(Original post by bl0bf1sh)
using the respective masses and Mr, can you work out the moles of SiO2 and C present?
Yes and I got
Moles for SiO2=0.25 and C= 0.7083
0
3 months ago
#4
have a look at the ratio SiO2:C in the equation
using your calculated numbers, how many moles of SiO2 are needed to react with the C present (or vice versa)?
0
#5
(Original post by bl0bf1sh)
have a look at the ratio SiO2:C in the equation
using your calculated numbers, how many moles of SiO2 are needed to react with the C present (or vice versa)?
0.25 moles of SiO2 is needed to react with 0.2361 or 0.24 moles of C
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3 months ago
#6
and how many moles of C are actually present?
0
#7
(Original post by bl0bf1sh)
and how many moles of C are actually present?
0.7082
0
3 months ago
#8
so which is the limiting reagent?
(i.e. the other must be in excess)
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#9
(Original post by bl0bf1sh)
so which is the limiting reagent?
(i.e. the other must be in excess)
carbon
0
3 months ago
#10
so SiO2 is in excess! boom well done
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#11
(Original post by bl0bf1sh)
so SiO2 is in excess! boom well done
Thank you
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