How much hydrogen gas is necessary to exert a pressure of 1.4 ATM at 430k if occupying a volume of 15.1 l

0.60 mol H₂

General Formula and Concepts:

Chemistry - Gas Laws

Ideal Gas Law: PV = nRT

Explanation:

Step 1: Define Variables

P = 1.4 atm

T = 430 K

R = 0.0821 (L · atm)/(mol · K)

V = 15.1 L

n = unknown

Step 2: Solve for n

Step 3: Check

We are given 2 sig figs as our lowest. Follow sig fig rules and round.

0.598816 mol H₂ ≈ 0.60 mol H₂

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.