Question

Hydrogen gas was cooled from 150 K to 50 K. Its new volume (V2) is 75 mL. What was its original volume (V1)?

Answer 1

Explanation:

57.3ml

we use Charles's law

to solve the question

Answer 2

Answer:

$\boxed {\boxed {\sf 225 \ mL}}$

Explanation:

The temperature and volume of the gas are changing, so we use Charles's Law. This states the temperature of a gas is directly proportional to the volume of a gas. The formula is:

$\frac{V_1}{T_1}=\frac{V_2}{T_2}$

The original volume is unknown. The new volume is 75 milliliters.

The gas is cooled from 150 Kelvin to 50 Kelvin, so the original temperature is 150 K and the new temperature is 50 K.

We know that:

• T₁= 150 K
• V₂= 75 mL
• T₂= 50 K

Substitute the values into the formula.

$\frac {V_1}{150 \ K}=\frac{ 75 \ mL}{50 \ K}$

Since we are solving for the original volume, we must isolate the variable V₁.

It is being divided by 150 K. The inverse of division is multiplication, so we multiply both sides by 150 K.

$150 \ K *\frac {V_1}{150 \ K}=\frac{ 75 \ mL}{50 \ K}* 150 \ K$

$V_1=\frac{ 75 \ mL}{50 \ K}* 150 \ K$

The units of Kelvin (K) cancel.

$V_1= \frac{ 75 \ mL}{50 }* 150$

$V_1=1.5 * 150 \ mL$

$V_1= 225 \ mL$

The original volume is 225 milliliters.