Question

a 5.00 l air sample has a pressure of 107 kpa at a temperature of -50.0 C. if the temperature is raised to 102 C and the volume expands to 7.00 L, what will the new pressure be

Answer 1

Answer:

The new pressure would be 128.5 kPa

Explanation:

We need to use the combined gas law to solve this problem:

$\frac{P_{1}V_{1} }{T_{1}}=\frac{P_{2}V_{2} }{T_{2}}$

But before using this equation we must convert °C into K.

• -50.0°C = 223.16 K
• 102 °C = 375.16 K

Then we put the data in the equation and solve for P₂:

$\frac{107kPa*5.00L}{223.16K}= \frac{P_{2}*7.00L}{375.16K}$

$P_{2}=128.5kPa$

Answer 2

You have to use the combined gas law (P₁V₁/T₁=P₂V₂/T₂) and solve for P₂ to get P₂=P₁V₁T₂/T₁V₂.

You need to convert all of the temperature values into terms of Kelvin so -50°C turns into 223K and 102°C turns to 375K.  After you make that conversion you can just plug in all of the values into the idea gas law and you should get P₂=228.5kpa.

I hope this helps.  Let me know if anything is unclear.