Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water. What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane (density of heptane = 0.6838 g/mL)

Question

Quizplus · Accepted Answer

First, we need to calculate the mass of heptane using its density:
Density of heptane = 0.6838 g/mL
Volume of heptane = 25.5 mL
Mass of heptane = density x volume = 0.6838 g/mL x 25.5 mL = 17.4465 g

Next, we need to balance the chemical equation:
C7H16 + 11O2 → 7CO2 + 8H2O

From the balanced equation, we can see that for every 1 mol of heptane, we need 11 mol of oxygen gas. The molar mass of heptane is 100.205 g/mol (7 x 12.01 g/mol + 16 x 1.01 g/mol), so the number of moles of heptane in 17.4465 g is:
n = mass / molar mass = 17.4465 g / 100.205 g/mol = 0.1741 mol

Therefore, the minimum mass of oxygen required is:
Mass of oxygen = n x 11 x molar mass of oxygen = 0.1741 mol x 11 x 32 g/mol = 61.3072 g

Rounding to the appropriate number of significant figures gives the final answer of 61.3 g of oxygen.

Liquid Heptane, C7H16, Burns in Oxygen Gas to Yield Carbon

Liquid Heptane, C₇H₁₆, Burns in Oxygen Gas to Yield Carbon