Question

Methanol is an ingredient in windshield washer fluid and ingesting as little as 4 mL can cause blindness in humans.

In the reaction below, methanol is produced from carbon dioxide and hydrogen gas. If the reaction has a △H rxn = -128 kJ, how much heat is released when 16.8 g CO is reacted?

CO + 2H₂ → CH₃OH

A. -76.8 kJ

B. -128 kJ

C. -16.8 kJ

D. -0.600 kJ

Answer 1

The correct answer is A. -76.8 kJ, which is the amount of heat released when 16.8 g of CO is reacted to produce methanol. This was calculated by first finding the number of moles of CO and then using the given ΔH rxn to determine the total heat released.

Step-by-step explanation:

The question asks how much heat is released when 16.8 g of carbon monoxide (CO) is reacted to produce methanol (CH3OH) through the reaction CO + 2H2 → CH3OH, given that ΔH rxn = -128 kJ. To solve this, we need to calculate the number of moles of CO that corresponds to 16.8 g and then determine the amount of heat released based on the stoichiometry of the reaction and the given enthalpy change.

Calculation Steps:

Calculate the molar mass of CO, which is 12.01 g/mol (carbon) + 16.00 g/mol (oxygen) = 28.01 g/mol.

Find the moles of CO by dividing the given mass by the molar mass: 16.8 g CO ÷ 28.01 g/mol = 0.600 moles CO.

Since 1 mole of CO releases -128 kJ, 0.600 moles will release 0.600 × (-128 kJ) = -76.8 kJ.

Therefore, the correct answer is A. -76.8 kJ, which is the amount of heat released when 16.8 g of CO is reacted to produce methanol.