Question

At 570. mmHg and 25 °C, a gas sample has a volume of 2270 mL. What is the final pressure (in mmHg) at a volume of 1250 mL and a temperature of 175 °C? 1560 mmHg 210 mmHg 7000 mmHg 690 mmHg 470 mmHg

Answer 1

Answer:

1560 mmHg is the final pressure

Explanation:

To solve this problem we need to apply the Ideal Gases Law Equation:

P . V = n .  R . T

First of all, we need to convert the volume to L, T° to Absolute T° (T°C + 273) and pressure from mmHg to atm

570 mmHg . 1atm/760 mmHg = 0.75 atm

25°C + 273 = 298K

175°C + 273 = 448K

2270 mL . 1L/1000mL = 2.27L

1250 mL . 1L/1000mL = 1.25L

P.V = n . R. T is the main equation but in both cases n and R are constant. We can ignore them, so we make this formula for each situation:

P . V / T = n . R  →  P₁ . V₁ / T₁ = P₂ . V₂ / T₂

We replace data: 0.75 atm . 2.27L / 298K = P₂ . 1.25L / 448K

(0.75 atm . 2.27L / 298K). 448K = P₂ . 1.25L

2.56 atm.L = P₂ . 1.25L → P₂ = 2.56atm.L / 1.25L = 2.05 atm

We finally convert the atm to mmHg to reach the answer

2.05 atm . 760 mmHg / 1atm = 1556 mmHg ≅ 1560 mmHg