Question

A chemist measures the energy change AH during the following reaction:

CH4(9)+202(9) + CO2(9)+2H2O(1)
AH=-882. kJ
Use the information to answer the following questions.
This reaction is...
Suppose 83.4 g of CH4 react.
endothermic.
exothermic.
Yes, absorbed.
Yes, released.
No.
x
Will any heat be released or absorbed?
If you said heat will be released or absorbed in the second part of this question, calculate how much heat will be released or absorbed.
Be sure your answer has the correct number of significant digits.

Answer 1

The reaction of CH4 with O2 to form CO2 and H2O is exothermic, releasing heat. For 83.4 g of CH4, the amount of heat released is calculated to be -4586.4 kJ, indicating an exothermic process with heat given off to the surroundings.

Step-by-step explanation:

The reaction CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) ΔH=-882 kJ is an exothermic reaction because it has a negative enthalpy change (ΔH), indicating that heat is released to the surroundings. If 83.4 g of CH4 were to react, knowing that the molar mass of CH4 is about 16.04 g/mol, we can calculate the moles of CH4 and then use the enthalpy change to find out the total heat released.

To calculate the heat released: First, find the moles of CH4: 83.4 g / 16.04 g/mol = 5.20 mol.

The reaction releases 882 kJ for every mole of CH4 that reacts. Therefore, for 5.20 moles:

Heat released = -882 kJ/mol × 5.20 mol = -4586.4 kJ

Thus, the amount of heat released when 83.4 g of CH4 reacts is -4586.4 kJ, with the negative sign indicating the exothermic nature of the reaction.