How many grams of chlorine gas (cl2) are in a 17.8-liter sample at 1.1 atmospheres and 29°c? show all work used to solve this problem.

56.0 g

Explanation:

1) Data: 
mass, m = ?
Volume, V = 17.8 l
Pressure, P = 1.1 atm
Temperature, T = 29°C

molecule: Cl₂

2) Formulas:

i) ideal gas equation: PV = nRT

ii) m = n × molar mass

iii) molar mass = ∑ masses of all atoms in the chemical formula

3) Solution

i) n
n = PV / RT
R = universal constant of gases = 0.0821 atm×l / (K×mol)
T = 29 + 273.15 = 302.15K

n = [1.1 atm × 17.8 l ]/ [0.0821 atm×l / (k×mol) × 302.15 K] = 0.789 mol

ii) molar mass
Cl₂ ⇒ 2 × 35.5 g/mol = 71.0 g/mol

iii) mass in grams

mass = n × molar mass = 0.789 mol × 71.0 g/mol = 56.0 g

The answer is c. valence electrons