Question

Consider the generic reaction: 2 A(g) + B(g) → 2 C(g). If a flask initially contains 1.0 atm of A and 1.0 atm of B, what is the pressure in the flask if the reaction proceeds to completion? (Assume constant volume and temperature.)a. 1.0 atmb. 1.5 atmc. 2.0 atmd. 3.0 atm

Answer 1

Answer:

b. 1.5 atm.

Explanation:

Hello!

In this case, since the undergoing chemical reaction suggests that two moles of A react with one moles of B to produce two moles of C, for the final pressure we can write:

$P=P_A+P_B+P_C$

Now, if we introduce the stoichiometry, and the change in the pressure $x$ we can write:

$P=1.0-2x+1.0-x+2x$

Nevertheless, since the reaction goes to completion, all A is consumed and there is a leftover of B, and that consumed A is:

$x=\frac{1.0atm}{2}=0.5atm$

Thus, the final pressure is:

$P=1.0-2(0.5)+1.0-(0.5)+2(0.5)\\\\P=1.5atm$

Therefore the answer is b. 1.5 atm.

Best regards!