The molecular weight of a gas that has a density of 7.10 g/L at 25.0 C and 1.00 atm pressure is g/mol. A) 6.85× 10-2
B) 14.6
C) 28.0
D) 174

D) 174 g/mol

Explanation:

Step 1: Given and required data

Step 2: Convert "T" to Kelvin

We will use the following expression.

K = °C + 273.15

K = 25.0°C + 273.15

K = 298.2 K

Step 3: Calculate the molecular weight (M) of the gas

We will use the following expression derived from the ideal gas equation.

ρ = P × M / R × T

M = ρ × R × T / P

M = 7.10 g/L × (0.0821 atm.L/mol.K) × 298.2 K / 1.00 atm

M = 174 g/mol

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6