Question

What is the pressure, in mmhg, of a 4.00 g sample of o2 gas, which has a temperature of 30.0 °c, and a volume of 3000 ml?

Answer 1

Answer:- Pressure of the gas is 790.4 mmHg.

Solution:- Mass of the gas oxygen gas is 4.00 g, temperature is 30.0 degree C and volume is 3000 mL and it asks to calculate the pressure of the gas.

It is based on ideal gas law equation, PV = nRT

Where, P is pressure, V is volume, n is number of moles, R is the universal gas constant and T is temperature.

Let's convert the mass to moles on dividing the grams by molar mass. Molar mass of oxygen is 32 gram per mol.

n = $4.00g(\frac{1mol}{32g})$

n = 0.125 moles

Convert degree C to kelvin, for this we add 273.

T = 30.0 + 273 = 303 K

Convert mL to L. For this we divide the given volume by 1000.

V = $3000mL(\frac{1L}{1000mL})$

V = 3 L

Value of R is 0.0821 atm.L per mol per K.

The equation is rearranged for the pressure as:

$P=\frac{nRT}{V}$

Let's plug in the values in the equation to calculate the pressure, P.

$P=\frac{0.125*0.0821*303}{3}$

P = 1.04 atm

They want answer in mmHg, so let's convert the pressure unit from atm to mmHg.

1 atm = 760 mmHg

so, $1.04atm(\frac{760mmHg}{1atm})$

= 790.4 mmHg

So, the pressure of the gas is 790.4 mmHg.