a sample of helium gas occupies 12.9 l at 315 k and 1.20 atm. how many moles of helium does the sample…

a sample of helium gas occupies 12.9 l at 315 k and 1.20 atm. how many moles of helium does the sample contain? ______ mol he round your answer to 3 significant digits. do not include units in your answer.

a sample of helium gas occupies 12.9 l at 315 k and 1.20 atm. how many moles of helium does the sample contain? ______ mol he round your answer to 3 significant digits. do not include units in your answer.

Answer

Explanation:

Step1: Identify the ideal - gas law formula

The ideal - gas law is $PV = nRT$, where $P$ is pressure, $V$ is volume, $n$ is the number of moles, $R$ is the ideal - gas constant ($R=0.0821\ \text{L}\cdot\text{atm}/\text{mol}\cdot\text{K}$), and $T$ is temperature in Kelvin. We want to solve for $n$, so we can re - arrange the formula to $n=\frac{PV}{RT}$.

Step2: Substitute the given values

We are given that $P = 1.20\ \text{atm}$, $V=12.9\ \text{L}$, $T = 315\ \text{K}$, and $R = 0.0821\ \text{L}\cdot\text{atm}/\text{mol}\cdot\text{K}$. $n=\frac{1.20\times12.9}{0.0821\times315}$

Step3: Calculate the value of $n$

First, calculate the numerator: $1.20\times12.9 = 15.48$. Then, calculate the denominator: $0.0821\times315=25.8615$. Now, divide the numerator by the denominator: $n=\frac{15.48}{25.8615}\approx0.598$.

Answer:

0.598