ONE-EIGHTH STAGE 2026
Aburi Girl's SHS: 38 points
St. Joseph's Seminary SHS: 20 points
Fafraha Community SHS: 12 points
St. John's Grammar School: 40 points
Mpraeso SHS: 23 points
Tema Secondary School: 13 points
St. Augustine's College
Anlo SHS
Kumasi High School
ROUND 2 - SPEED RACE
QUESTION
Calculate the volume of carbon dioxide, S.T.P, produced on the complete combustion of 5.80 kilograms of butane.
Molar volume is 22.4 decimeters cubed.
ANSWER: $8.96\times10^3\text{ dm}^3$
SOLUTION:
$V(CO_2) = \dfrac{m}{M}\times4\times V_m$
$V(CO_2) = \dfrac{5800}{58}\times4\times22.4$
$V(CO_2) = 100\times4\times22.4$
$V(CO_2) = 400\times22.4$
$V(CO_2) = 8960\text{ dm}^3$
$V(CO_2) = 8.96\times10^3\text{ dm}^3$
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PRACTICE QUESTIONS
1. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 4.40 kg of propane. (C = 12, H = 1)
ANSWER: $6.72\times10^{3}$ dm³
SOLUTION:
$C_3H_8+5O_2\rightarrow3CO_2+4H_2O$
$M(C_3H_8) = 3(12)+8(1)$
$M(C_3H_8) = 44\text{ g/mol}$
$m = 4.40\times10^3\text{ g}$
$n(C_3H_8) = \dfrac{4.40\times10^3}{44}$
$n(C_3H_8) = 1.00\times10^{2}\text{ mol}$
$n(CO_2) = 3\times1.00\times10^{2}$
$n(CO_2) = 3.00\times10^{2}\text{ mol}$
$V(CO_2) = 3.00\times10^{2}\times22.4$
$V(CO_2) = 6.72\times10^{3}\text{ dm}^3$
2. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 3.20 kg of methane. (C = 12, H = 1)
ANSWER: $4.48\times10^{3}$ dm³
SOLUTION:
$CH_4+2O_2\rightarrow CO_2+2H_2O$
$M(CH_4) = 12+4(1)$
$M(CH_4) = 16\text{ g/mol}$
$m = 3.20\times10^3\text{ g}$
$n(CH_4) = \dfrac{3.20\times10^3}{16}$
$n(CH_4) = 2.00\times10^{2}\text{ mol}$
$n(CO_2) = 1\times2.00\times10^{2}$
$n(CO_2) = 2.00\times10^{2}\text{ mol}$
$V(CO_2) = 2.00\times10^{2}\times22.4$
$V(CO_2) = 4.48\times10^{3}\text{ dm}^3$
3. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 1.50 kg of ethane. (C = 12, H = 1)
ANSWER: $2.24\times10^{3}$ dm³
SOLUTION:
$C_2H_6+\dfrac{7}{2}O_2\rightarrow2CO_2+3H_2O$
$M(C_2H_6) = 2(12)+6(1)$
$M(C_2H_6) = 30\text{ g/mol}$
$m = 1.50\times10^3\text{ g}$
$n(C_2H_6) = \dfrac{1.50\times10^3}{30}$
$n(C_2H_6) = 50.0\text{ mol}$
$n(CO_2) = 2\times50.0$
$n(CO_2) = 1.00\times10^{2}\text{ mol}$
$V(CO_2) = 1.00\times10^{2}\times22.4$
$V(CO_2) = 2.24\times10^{3}\text{ dm}^3$
4. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 2.90 kg of butane. (C = 12, H = 1)
ANSWER: $4.48\times10^{3}$ dm³
SOLUTION:
$C_4H_{10}+\dfrac{13}{2}O_2\rightarrow4CO_2+5H_2O$
$M(C_4H_{10}) = 4(12)+10(1)$
$M(C_4H_{10}) = 58\text{ g/mol}$
$m = 2.90\times10^3\text{ g}$
$n(C_4H_{10}) = \dfrac{2.90\times10^3}{58}$
$n(C_4H_{10}) = 50.0\text{ mol}$
$n(CO_2) = 4\times50.0$
$n(CO_2) = 2.00\times10^{2}\text{ mol}$
$V(CO_2) = 2.00\times10^{2}\times22.4$
$V(CO_2) = 4.48\times10^{3}\text{ dm}^3$
5. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 1.44 kg of pentane. (C = 12, H = 1)
ANSWER: $2.24\times10^{3}$ dm³
SOLUTION:
$C_5H_{12}+8O_2\rightarrow5CO_2+6H_2O$
$M(C_5H_{12}) = 5(12)+12(1)$
$M(C_5H_{12}) = 72\text{ g/mol}$
$m = 1.44\times10^3\text{ g}$
$n(C_5H_{12}) = \dfrac{1.44\times10^3}{72}$
$n(C_5H_{12}) = 20.0\text{ mol}$
$n(CO_2) = 5\times20.0$
$n(CO_2) = 1.00\times10^{2}\text{ mol}$
$V(CO_2) = 1.00\times10^{2}\times22.4$
$V(CO_2) = 2.24\times10^{3}\text{ dm}^3$
6. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 5.60 kg of ethene. (C = 12, H = 1)
ANSWER: $8.96\times10^{3}$ dm³
SOLUTION:
$C_2H_4+3O_2\rightarrow2CO_2+2H_2O$
$M(C_2H_4) = 2(12)+4(1)$
$M(C_2H_4) = 28\text{ g/mol}$
$m = 5.60\times10^3\text{ g}$
$n(C_2H_4) = \dfrac{5.60\times10^3}{28}$
$n(C_2H_4) = 2.00\times10^{2}\text{ mol}$
$n(CO_2) = 2\times2.00\times10^{2}$
$n(CO_2) = 4.00\times10^{2}\text{ mol}$
$V(CO_2) = 4.00\times10^{2}\times22.4$
$V(CO_2) = 8.96\times10^{3}\text{ dm}^3$
7. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 2.10 kg of propene. (C = 12, H = 1)
ANSWER: $3.36\times10^{3}$ dm³
SOLUTION:
$C_3H_6+\dfrac{9}{2}O_2\rightarrow3CO_2+3H_2O$
$M(C_3H_6) = 3(12)+6(1)$
$M(C_3H_6) = 42\text{ g/mol}$
$m = 2.10\times10^3\text{ g}$
$n(C_3H_6) = \dfrac{2.10\times10^3}{42}$
$n(C_3H_6) = 50.0\text{ mol}$
$n(CO_2) = 3\times50.0$
$n(CO_2) = 1.50\times10^{2}\text{ mol}$
$V(CO_2) = 1.50\times10^{2}\times22.4$
$V(CO_2) = 3.36\times10^{3}\text{ dm}^3$
8. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 4.30 kg of hexane. (C = 12, H = 1)
ANSWER: $6.72\times10^{3}$ dm³
SOLUTION:
$C_6H_{14}+\dfrac{19}{2}O_2\rightarrow6CO_2+7H_2O$
$M(C_6H_{14}) = 6(12)+14(1)$
$M(C_6H_{14}) = 86\text{ g/mol}$
$m = 4.30\times10^3\text{ g}$
$n(C_6H_{14}) = \dfrac{4.30\times10^3}{86}$
$n(C_6H_{14}) = 50.0\text{ mol}$
$n(CO_2) = 6\times50.0$
$n(CO_2) = 3.00\times10^{2}\text{ mol}$
$V(CO_2) = 3.00\times10^{2}\times22.4$
$V(CO_2) = 6.72\times10^{3}\text{ dm}^3$
9. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 2.28 kg of octane. (C = 12, H = 1)
ANSWER: $3.58\times10^{3}$ dm³
SOLUTION:
$C_8H_{18}+\dfrac{25}{2}O_2\rightarrow8CO_2+9H_2O$
$M(C_8H_{18}) = 8(12)+18(1)$
$M(C_8H_{18}) = 114\text{ g/mol}$
$m = 2.28\times10^3\text{ g}$
$n(C_8H_{18}) = \dfrac{2.28\times10^3}{114}$
$n(C_8H_{18}) = 20.0\text{ mol}$
$n(CO_2) = 8\times20.0$
$n(CO_2) = 1.60\times10^{2}\text{ mol}$
$V(CO_2) = 1.60\times10^{2}\times22.4$
$V(CO_2) \approx 3.58\times10^{3}\text{ dm}^3$
10. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 1.30 kg of ethyne. (C = 12, H = 1)
ANSWER: $2.24\times10^{3}$ dm³
SOLUTION:
$C_2H_2+\dfrac{5}{2}O_2\rightarrow2CO_2+H_2O$
$M(C_2H_2) = 2(12)+2(1)$
$M(C_2H_2) = 26\text{ g/mol}$
$m = 1.30\times10^3\text{ g}$
$n(C_2H_2) = \dfrac{1.30\times10^3}{26}$
$n(C_2H_2) = 50.0\text{ mol}$
$n(CO_2) = 2\times50.0$
$n(CO_2) = 1.00\times10^{2}\text{ mol}$
$V(CO_2) = 1.00\times10^{2}\times22.4$
$V(CO_2) = 2.24\times10^{3}\text{ dm}^3$
11. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 8.70 kg of butane. (C = 12, H = 1)
ANSWER: $1.34\times10^{4}$ dm³
SOLUTION:
$C_4H_{10}+\dfrac{13}{2}O_2\rightarrow4CO_2+5H_2O$
$M(C_4H_{10}) = 4(12)+10(1)$
$M(C_4H_{10}) = 58\text{ g/mol}$
$m = 8.70\times10^3\text{ g}$
$n(C_4H_{10}) = \dfrac{8.70\times10^3}{58}$
$n(C_4H_{10}) = 1.50\times10^{2}\text{ mol}$
$n(CO_2) = 4\times1.50\times10^{2}$
$n(CO_2) = 6.00\times10^{2}\text{ mol}$
$V(CO_2) = 6.00\times10^{2}\times22.4$
$V(CO_2) \approx 1.34\times10^{4}\text{ dm}^3$
12. QUESTION: Calculate the volume of carbon dioxide, at s.t.p., produced on the complete combustion of 5.00 kg of heptane. (C = 12, H = 1)
ANSWER: $7.84\times10^{3}$ dm³
SOLUTION:
$C_7H_{16}+11O_2\rightarrow7CO_2+8H_2O$
$M(C_7H_{16}) = 7(12)+16(1)$
$M(C_7H_{16}) = 100\text{ g/mol}$
$m = 5.00\times10^3\text{ g}$
$n(C_7H_{16}) = \dfrac{5.00\times10^3}{100}$
$n(C_7H_{16}) = 50.0\text{ mol}$
$n(CO_2) = 7\times50.0$
$n(CO_2) = 3.50\times10^{2}\text{ mol}$
$V(CO_2) = 3.50\times10^{2}\times22.4$
$V(CO_2) = 7.84\times10^{3}\text{ dm}^3$