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) A)8.14 g B)89.6 g C)61.3 g D)30.6 g E)5.57 g

Question

Quizplus · Accepted Answer

First, we need to find the mass of 25.5 mL of heptane:
mass = volume x density = 25.5 mL x 0.6838 g/mL = 17.4681 g

Next, we need to balance the equation for the combustion of heptane:
C7H16 + 11 O2 → 7 CO2 + 8 H2O

From the balanced equation, we see that the ratio of heptane to oxygen required is 1:11. Therefore, the minimum mass of oxygen required is:
(11/1) x 17.4681 g = 192.1491 g

However, we need to convert this mass from grams to moles using the molar mass of oxygen (32.00 g/mol):
192.1491 g / 32.00 g/mol = 6.003 g = 0.188 mol

Therefore, the minimum mass of oxygen required for the complete reaction of heptane is 0.188 mol or:
0.188 mol x 32.00 g/mol = 6.016 g, which is closest to choice C (61.3 g).

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

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