Let's solve each of these
Combined Gas Law problems step by step.
The
Combined Gas Law is:
$$
\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}
$$
Where:
- $ P $ = pressure (in atm)
- $ V $ = volume (in liters)
- $ T $ = temperature (in Kelvin, K)
Remember: Convert Celsius to Kelvin using $ T(K) = T(°C) + 273 $
---
Problem 1
Given:
- $ P_1 = 12 \text{ atm} $
- $ V_1 = 23 \text{ L} $
- $ T_1 = 200 \text{ K} $
- $ P_2 = 14 \text{ atm} $
- $ T_2 = 300 \text{ K} $
- Find: $ V_2 = ? $
Use the combined gas law:
$$
\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}
$$
Solve for $ V_2 $:
$$
V_2 = V_1 \times \frac{P_1}{P_2} \times \frac{T_2}{T_1}
$$
Plug in values:
$$
V_2 = 23 \times \frac{12}{14} \times \frac{300}{200}
$$
$$
V_2 = 23 \times 0.8571 \times 1.5
$$
$$
V_2 = 23 \times 1.2857 \approx 29.57 \text{ L}
$$
✔ Answer: $ \boxed{29.6} $ liters (rounded to one decimal place)
---
Problem 2
Given:
- $ V_1 = 17 \text{ L} $
- $ P_1 = 2.3 \text{ atm} $
- $ T_1 = 299 \text{ K} $
- $ T_2 = 350 \text{ K} $
- $ P_2 = 1.5 \text{ atm} $
- Find: $ V_2 = ? $
Use:
$$
V_2 = V_1 \times \frac{P_1}{P_2} \times \frac{T_2}{T_1}
$$
$$
V_2 = 17 \times \frac{2.3}{1.5} \times \frac{350}{299}
$$
First, compute:
- $ \frac{2.3}{1.5} = 1.5333 $
- $ \frac{350}{299} \approx 1.1706 $
Now:
$$
V_2 = 17 \times 1.5333 \times 1.1706 \approx 17 \times 1.794 \approx 30.498 \text{ L}
$$
✔ Answer: $ \boxed{30.5} $ liters (rounded to one decimal place)
---
Problem 3
Given:
- $ V_1 = 28 \text{ L} $
- $ T_1 = 45^\circ C = 45 + 273 = 318 \text{ K} $
- $ V_2 = 34 \text{ L} $
- $ T_2 = 35^\circ C = 35 + 273 = 308 \text{ K} $
- $ P_2 = 2.0 \text{ atm} $
- Find: $ P_1 = ? $
Use:
$$
\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}
$$
Solve for $ P_1 $:
$$
P_1 = P_2 \times \frac{V_2}{V_1} \times \frac{T_1}{T_2}
$$
$$
P_1 = 2.0 \times \frac{34}{28} \times \frac{318}{308}
$$
Compute:
- $ \frac{34}{28} = 1.2143 $
- $ \frac{318}{308} \approx 1.0325 $
$$
P_1 = 2.0 \times 1.2143 \times 1.0325 \approx 2.0 \times 1.252 \approx 2.504 \text{ atm}
$$
✔ Answer: $ \boxed{2.5} $ atm (rounded to one decimal place)
---
Problem 4
Given:
- $ T_1 = 14^\circ C = 14 + 273 = 287 \text{ K} $
- $ V_1 = 4.5 \text{ L} $
- $ T_2 = 29^\circ C = 29 + 273 = 302 \text{ K} $
- Pressure is constant → Use
Charles’s Law: $ \frac{V_1}{T_1} = \frac{V_2}{T_2} $
So:
$$
V_2 = V_1 \times \frac{T_2}{T_1} = 4.5 \times \frac{302}{287}
$$
$$
\frac{302}{287} \approx 1.0523
$$
$$
V_2 = 4.5 \times 1.0523 \approx 4.735 \text{ L}
$$
✔ Answer: $ \boxed{4.7} $ liters (rounded to one decimal place)
---
✔ Final Answers Summary:
1) $ \boxed{29.6} $ L
2) $ \boxed{30.5} $ L
3) $ \boxed{2.5} $ atm
4) $ \boxed{4.7} $ L
Let me know if you'd like a visual explanation or help with units!
Parent Tip: Review the logic above to help your child master the concept of combined gas law problems worksheet.