Someone please help (mole calculations)

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username3787036
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#1
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#1
This ism my homework and I really don't know how to do it

Calcium carbonate breaks down on heating to produce calcium oxide and carbon dioxide gas.
CaCO3 ® CaO + CO2
A student heats 15 g of calcium carbonate strongly in a crucible.
Relative atomic masses (Ar): Ca = 40, C = 12, O = 16.
4 / 4
a Calculate the number of moles in 15 g of calcium carbonate. (2 marks)
b Use your answer to part a to determine the number of moles of calcium oxide that will be produced. (1 mark)
c Calculate the mass of calcium oxide produced by this reaction. (2 marks)

4 A student is preparing a sample of sodium nitrate, NaNO3.
She mixes 17 g of sodium oxide with an excess of nitric acid. The equation for the reaction is:
Na2O + 2HNO3 ® 2NaNO3 + H2O
Relative atomic masses (Ar): Na = 23, O = 16, N = 14, H = 1.
a Calculate the number of moles in 17 g of sodium oxide. (2 marks)
b Calculate the maximum mass of sodium nitrate that can be produced in this reaction. (3 marks)

5 Aluminium and iron oxide (Fe2O3) react together to produce aluminium oxide (Al2O3). The equation for the reaction is:
2Al + Fe2O3 ® Al2O3 + 2Fe
Calculate the mass of iron that is produced by reacting 20 g of iron oxide with an excess of aluminium.
Relative atomic masses (Ar): Al = 27, O = 16, Fe = 56. (4 marks)
Last edited by username3787036; 2 years ago
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Thiexp53
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Use the formula: m (mass) / Mr (relative molecular mass) = n (number of moles)
If there is an equation such as HCl + NaOH > NaCl + H2O then that means for every one mole of HCl reacted, one mole of NaCl will be produced.
And if there is an equation such as C3H8 + 5O2 > 4H2O + 3CO2 then it means for every one mole of C3H8 reacted, 4 moles of H2O will be produced etc.
Using that information have another go, that should be all you need to work them out. (Unless this is too late because I know this is a pretty late reply, but I didn't want to leave this unanswered).
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tpruett1234
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(Original post by Thiexp53)
Use the formula: m (mass) / Mr (relative molecular mass) = n (number of moles)
If there is an equation such as HCl + NaOH > NaCl + H2O then that means for every one mole of HCl reacted, one mole of NaCl will be produced.
And if there is an equation such as C3H8 + 5O2 > 4H2O + 3CO2 then it means for every one mole of C3H8 reacted, 4 moles of H2O will be produced etc.
Using that information have another go, that should be all you need to work them out. (Unless this is too late because I know this is a pretty late reply, but I didn't want to leave this unanswered).
So what did you get as your overall answer?

Thanks,

Tom
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