Question

If 5.0 liters H2 (g) at STP is heated to a temperature of 985, pressure remaining constant, the new volume of the gas will be?

Answer 1

Answer:

$V_2=18 \ L \ H_2$

General Formulas and Concepts:

Chemistry - Gas Laws

• STP (Standard Conditions for Temperature and Pressure) = 22.4 L per mole at 1 atm, 273 K
• Charles' Law: $\frac{V_1}{T_1} =\frac{V_2}{T_2}$

Explanation:

Step 1: Define

Initial Volume: 5.0 L H₂ gas

Initial Temp: 273 K

Final Temp: 985 K

Final Volume: ?

Step 2: Solve for new volume

1. Substitute:                    $\frac{5 \ L \ H_2}{273 \ K} =\frac{x \ L \ H_2}{985 \ K}$
2. Cross-multiply:             $(5 \ L \ H_2)(985 \ K) = (x \ L \ H_2)(273 \ K)$
3. Multiply:                        $4925 \ L \ H_2 \cdot K = 273x \ L \ H_2 \cdot K$
4. Isolate x:                       $18.0403 \ L \ H_2 = x$
5. Rewrite:                         $x=18.0403 \ L \ H_2$

Step 3: Check

We are given 2 sig figs as the smallest. Follow sig fig rules and round.

$18.0403 \ L \ H_2 \approx 18 \ L \ H_2$