Question

dinitrogen difluoride gas is collected at 11.0°c in an evacuated flask with a measured volume of 30.0 l. when all the gas has been collected, the pressure in the flask is measured to be 0.180 atm. calculate the mass and number of moles of dinitrogen difluoride gas that were collected. be sure your answer has the correct number of significant digits. mass: g mole: mol

Explanation:

Step1: Convert temperature to Kelvin

$$T = 11.0+273.15=284.15\ K$$

Step2: Use ideal gas law \(PV = nRT\) to find moles \(n\)

\(R = 0.0821\ L\cdot atm/(mol\cdot K)\), \(P = 0.180\ atm\), \(V = 30.0\ L\)
$$n=\frac{PV}{RT}=\frac{0.180\times30.0}{0.0821\times284.15}$$
$$n=\frac{5.4}{23.328715}\approx0.231\ mol$$

Step3: Calculate molar mass of \(N_2F_2\)

Molar mass of \(N = 14.01\ g/mol\), molar mass of \(F=19.00\ g/mol\)
\(M = 2\times14.01 + 2\times19.00=28.02 + 38.00 = 66.02\ g/mol\)

Step4: Calculate mass \(m\)

$$m=n\times M=0.231\times66.02\approx15.3\ g$$

Answer:

mass: \(15.3\ g\)
mole: \(0.231\ mol\)