Question

carbon dioxide gas is collected at 13.0 °c in an evacuated flask with a measured volume of 20.0 l. when all the gas has been collected, the pressure in the flask is measured to be 0.230 atm. calculate the mass and number of moles of carbon dioxide 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

$$T = 13.0 + 273.15 = 286.15\ \text{K}$$

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

\(R = 0.0821\ \text{L·atm/(mol·K)}\), \(P = 0.230\ \text{atm}\), \(V = 20.0\ \text{L}\)
$$n=\frac{PV}{RT}=\frac{0.230\times20.0}{0.0821\times286.15}$$
$$n=\frac{4.6}{23.503015}\approx0.196\ \text{mol}$$

Step3: Calculate mass using molar mass of \(CO_2\) (\(M = 44.01\ \text{g/mol}\))

$$m=n\times M = 0.196\times44.01$$
$$m = 8.63\ \text{g}$$

Answer:

mass: \(8.63\ \text{g}\)
mole: \(0.196\ \text{mol}\)