Question

gas stoichiometry
use ( pv = nrt ) to solve for the volume of one mole of gas at stp:
look familiar? this is the molar volume of a gas at stp. work stoichiometry problems using your favorite method, dimensional analysis, mole map, the table way...just work fast! use the ideal gas law to convert quantities that are not at stp.
exercise 13 gas stoichiometry 1
a sample of nitrogen gas has a volume of 1.75 l at stp. how many moles of ( n_2 ) are present?
gases

Explanation:

Step1: Recall the molar volume at STP

At STP (Standard Temperature and Pressure: \(T = 273\space K\), \(P=1\space atm\)), the molar volume \(V_m\) of an ideal gas is \(V_m = 22.4\space L/mol\).

Step2: Use the formula \(n=\frac{V}{V_m}\)

We know that \(V = 1.75\space L\) and \(V_m=22.4\space L/mol\). Substitute these values into the formula: \(n=\frac{1.75\space L}{22.4\space L/mol}\)

$$n=\frac{1.75}{22.4}\space mol= 0.078125\space mol$$

Answer:

\(0.0781\space mol\) (rounded to four - significant figures)