Question

One way to produce methanol:

CO + 2H₂ → CH₃OH
This reaction has a △H rxn = -128 kj. how much heat (in kj) is released when you completely react 4.04 g CO?

O -517 kJ
O -18.5 kJ
O -14500 kJ
O -128 kJ

Answer 1

O -18.5 kJ The heat released when 4.04 g of CO reacts to form methanol is calculated by first finding the number of moles of CO, then multiplying by the enthalpy change of the reaction. The answer is -18.5 kJ, indicating an exothermic reaction.

Step-by-step explanation:

The question involves calculating the amount of heat released when 4.04 g of carbon monoxide (CO) reacts with hydrogen gas (H₂) to produce methanol (CH₃OH), given the reaction CO + 2H₂ → CH₃OH with a enthalpy change (ΔH rxn) of -128 kJ.

First, calculate the number of moles of CO in 4.04 g using its molecular weight (28.01 g/mol):

Number of moles of CO = mass of CO / molar mass of CO
Number of moles of CO = 4.04 g / 28.01 g/mol
Number of moles of CO = 0.144 moles

Since the reaction releases 128 kJ per mole of CO, we multiply the number of moles by the enthalpy change to determine the total heat released:

Total heat released = number of moles of CO * ΔH rxn
Total heat released = 0.144 moles * -128 kJ/mole
Total heat released = -18.5 kJ

The negative sign indicates that the reaction is exothermic and heat is released to the surroundings. So the correct answer for heat released when 4.04 g of CO is completely reacted to form methanol is -18.5 kJ.