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

Step-by-step explanation:

57.3ml

we use Charles's law

to solve the question

Answer 2

`\boxed {\boxed {\sf 225 \ mL}}`

Step-by-step 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:

`(V_1)/(T_1)=(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}=( 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}=( 75 \ mL)/(50 \ K)* 150 \ K`

`V_1=( 75 \ mL)/(50 \ K)* 150 \ K`

The units of Kelvin (K) cancel.

`V_1= ( 75 \ mL)/(50 )* 150`

`V_1=1.5 * 150 \ mL`

`V_1= 225 \ mL`

The original volume is 225 milliliters.