Which of the following statements is true?

Question

For the chemical reaction H2 + CO2 H2O + CO, the energy contained in the reactants is 352 kJ, and the energy contained in the products is 394 kJ, assuming 1 mol of each substance is present. Which of the following statements is true?

1.) 42 kJ is released, and the reaction is exothermic.
2.) 42 kJ is released, and the reaction is endothermic.
3.) 42 kJ is absorbed, and the reaction is exothermic.
4.) 42 kJ is absorbed, and the reaction is endothermic

Answer 1

The only two answers which actually make sense are choice 1.) and choice 4.), the others are not even possible in the way they are stated.

When energy is absorbed, the process is endothermic. When energy is released, the process is exothermic. So when choice 2.) says that releasing energy is endothermic, and in choice 3.), it says that absorbing energy is exothermic...they are wrong.

To determine if energy is absorbed or released from the reaction, compare the energy states of the products and the reactants. If the energy of the products is greater than that of the reactants (delta H is postive) then the process is endothermic and energy is absorbed. if the energy of the products is less than the energy of the reactants (delta H is negative) then the process is exothermic and energy is released.

In your reactions, the energy of the products is greater than that of the reactants (394 kJ > 352 kJ), so 42 kJ of energy is absorbed in this endothermic reaction.
Thus, the correct answer is choice 4.).

Answer 2

Ok, it's been a very long time since I studied any of this, but if my memory serves me correctly ( and it might not) I would say #3. is correct. However, if it were me I would put that answer into your google search and see what it gives you.
Sorry I couldn't be more help, I'm old.. lol - been out of school for 26 years.

Answer 3

Home work again?