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as at 25 °C fills a container whose volume is 1.05 * 103 cm3. The container plus gas has a mass of 837.6 g. The container, when emptied of all gas, has a mass of 836.2 g. What is the density of the gas at 25 °C?

1 Answer

6 votes

Answer:

0.00133 g/cm^3 or 28.97 g/mol.

Step-by-step explanation:

To solve the problem, we'll need to use the ideal gas law: PV = nRT

Where:

P = Pressure (we'll assume atmospheric pressure, since it's not specified in the problem)

V = Volume (1.05 x 10^3 cm^3)

n = moles of gas

R = Gas Constant (0.08206 L.atm/K.mol)

T = Temperature (25 + 273.15 K = 298.15 K)

First, let's find the mass of the gas alone:

Mass of gas = Mass of container + gas - Mass of container Mass of gas = 837.6 g - 836.2 g

Mass of gas = 1.4 g

Next, we need to find the number of moles of gas:

n = m/M

where: m = mass of gas (1.4 g) M = molar mass of the gas (unknown)

We don't know the molar mass of the gas yet, so let's rearrange the ideal gas law to solve for it:

M = m/ (n/V) RT

Substitute the values we know so far:

M = 1.4 g / [(n/V)RT]

We'll need to find n/V to substitute into the equation. This can be found using the density formula:

Density = mass/volume

Rearrange the formula to solve for n/V:

n/V = Density / Molar mass

Substitute the values we know:

Density = mass/volume = 1.4 g / 1.05 x 10^3 cm^3

Density = 0.00133 g/cm^3

Substitute this value into the formula to find n/V: n/V = 0.00133 g/cm^3 / M

Substitute n/V into the equation to solve for M: M = 1.4 g / [(0.00133 g/cm^3 / M) (0.08206 L.atm/K.mol) (298.15 K) (1 cm^3 / 1 x 10^-6 L)]

Simplifying this equation gives: M = 28.97 g/mol

Therefore, the molar mass of the gas is approximately 28.97 g/mol.

User Nicholas Lu
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