Calcium carbonate decomposes at high temperatures to give calcium oxide and carb
ID: 1027807 • Letter: C
Question
Calcium carbonate decomposes at high temperatures to give calcium oxide and carbon dioxide. What volume of CO2 will be collected at 950 torr and 500C when 75.0 g of CaCO3 react?
CaCO3(s) -> CaO(s) + CO2(g)
How many mL of .250M KMnO4 are needed to react with 3.36g of FeSO4?
10FeSO4 + 2KMnO4 + 8H2SO4 -> 5Fe(SO4)3 + 2MnSO4 + 8H2O
Potassium chlorate reacts with hydrochloric acid to produce chlorine gas. What mass of KCLO3 is needed to make 4.50L of chlorine at 2.35 atm and 37.0C?
KClO3(g) + 6HCl(aq) -> KCl(aq) + 3Cl2(g) 3H20(l)
Explanation / Answer
1)
CaCO3(s) -> CaO(s) + CO2(g)
moles of CaCO3 = 75.0 / 100.087 = 0.749 mol
1 mol CaCO3 -----------> 1 mol CO2
0.749 mol CaCO3 ----------> ??
moles of CO2 = 0.749 mol
pressure = 950 torr = 1.25 atm
temperature = 500 oC = 773 K
P V = n R T
1.25 x V = 0.749 x 0.0821 x 773
V = 38.0
volume of CO2 = 38.0 L
3)
P V = n R T
2.35 x 4.50 = n x 0.0821 x 310
n = 0.4155
moles of Cl2 = 0.4155 mol
1 mol KClO3 ----------. 3 mol Cl2
?? ----------> 0.4155 mol Cl2
moles of KClO3 = 0.4155 / 3 = 0.1385
mass of KClO3 = 17.0 g