# A 5.00 L sample of helium at STP expands to 15.0 L. What is the new pressure on the gas?

May 7, 2018

${P}_{2}$ = 33.3 repeating kPa (kilopascals)

#### Explanation:

Boyle's Law
${P}_{1} {V}_{1}$ = ${P}_{2} {V}_{2}$

Standard Temperature and Pressure:
273.15K with an absolute pressure of 1 atm (up to 1982)
273.15K with an absolute pressure of 100 kPa (1982- present)

(100 kPa)(5.00L) = (${P}_{2}$)(15L)

Divide (100 kPa)(5.00L) by (15L) to isolate for ${P}_{2}$.

$\frac{100 \cdot 5}{15}$ = ${P}_{2}$

Simplify.

$\frac{500}{15}$ = ${P}_{2}$

${P}_{2}$ = 33.33333333333 kPa