Question

The two balanced equations (1) and (2) are for reactions in which gaseous carbon dioxide is produced from the combustion of (1) solid carbon (2) gaseous carbon monoxide.

1. C(s) + O2(g) CO2(g) + 94.0 kcal

2. CO(g) + ½O2(g) CO2(g) + 67.6 kcal

On the basis of the information given in equation (1) and assuming no change in temperature or pressure, one can correctly conclude that:
A) The rate of reaction is rapid.
B) The total number of moles of products is the same as the total number of moles of reactants.
C) The reaction is exothermic.
D) The weights of the products are greater than those of the reactants.
E) There will be an increase in the volume of the reactants and products taken together as the reaction proceeds.

Answer 1

C) The reaction is exothermic.

Step-by-step explanation:

The reaction 1 is:

C(s) + O₂(g) → CO₂(g) + 94.0 kcal

It's not possible to infer for only what is given if the rection is rapid or slow, it would be necessary to know the activation energy, so letter a is incorrect.

We can infer that there is 1 mol of C and 1 mol of O₂ forming 1 mol of CO₂, so there are 2 moles of reactants forming 1 mol of products, so letter b is incorrect.

In the reaction, there is 94.0 kcal being released. When energy (heat) is lost, the reaction is exothermic. So, letter c is the correct answer.

For the Lavoiser's Law, the weighs of the reactants must be equal to the weighs of the products, so letter d is incorrect.

The volume must remain constant if the reaction is taking place in a closed container because the pressure on the system depends only on the gas substances, and they are equal in number of moles for the reactants and the products (1 mol of O₂ and 1 mol of CO₂), because of that, the pressure is constant. The reaction is taking place at a constant temperature, so the volume must be constant too (ideal gas law). Besides that, if the reaction is taking place on an open container, the gas will be lost, so the volume must decrease. Then, letter e is incorrect.

Answer 2

The correct answer for the question that is being presented above is this one: "E) There will be an increase in the volume of the reactants and products taken together as the reaction proceeds." On the basis of the information given in equation (1) and assuming no change in temperature or pressure, one can correctly conclude that: E) There will be an increase in the volume of the reactants and products taken together as the reaction proceeds.