A2.35 g sample of an unknown gas at 55 ∘c and 1.05 atm is stored in a 1.85 l flask.

what is the density of the gas and molar mass

Molar mass =  32.64 g / mol.

The density of gas is 1.3 × 10⁻³g/mL.

Explanation:

Given data:

Mass of sample = 2.35 g

Pressure = 1.05 atm

Volume = 1.85 L    (1.85 × 1000 = 1850 ml)

Temperature = 55 °C    (55+ 273.15 = 328.15 K)

Density = ?

Formula:

d = m/ v

The volume of flask would be the volume of gas.

d = 2.35 g / 1850 mL = 0.0013 g/mL or 1.3 × 10⁻³g/mL

The density of gas is 1.3 × 10⁻³g/mL.

Molar mass:

Now we will calculate the moles of a gas first in order to find the molar mass of a gas.

Formula:

PV =nRT

n = number of moles.

n = PV / RT

n = 1.05 atm × 1.85 L / 0.0821 atm. dm³. K⁻¹ . mol⁻¹ × 328.15 K

n = 1.9425 atm . L / 26.941115 atm . dm.³mol⁻¹

n = 0.072 mol

Now we will find the molar mass.

Number of moles = mass / molar mass

0.072 mol = 2.35 g / molar mass

Molar mass = 2.35 g / 0.072 mol

Molar mass =  32.64 g / mol

answer: c. the experiment shows that the red substance experienced a chemical change.

explanation: chemical change is the change in which chemical composition of the substance changes. physical change is the change in which there is no change in chemical composition.

chemical changes are accompanied by following changes:

a) precipitate formation

b) energy is released or absorbed

c) formation of bubbles

d) change in color

as it is given that the red color has disappeared and there is production of gas, it means the red substance has undergone a chemical change.

e