Question

The gas inside a balloon is characterized by the following measurements: pressure =725.5 mmHg; volume = 400.0 mL; temperature =16.5 C

Answer 1

• The number of moles of gas in the ballon is 0.01606mol

Step-by-step explanation:

The question is "What is the number of moles of gas in the balloon?"

Solution

1. Data

a) p = 725.5 mmHg

b) V = 400.0mL

c) T = 16.5ºC

d) n = ?

2. Formula

Ideal gas equation:

• pV = nRT

3. Solution

a) Conversion of units:

• p = 725.5 mmHg × 1 atm / 760.0 mmHg = 0.954605 atm

• V = 400.0mL × 1L / 1,000mL = 0.4000L

• T = 16.5 + 273.15 K = 289.65K

b) Clear n from the formula:

• n = (pV)/(RT)

c) Substitute and compute:

• n = (0.954605atm × 0.4000L) / (0.08206atm·L/K·mol × 289.65)

• n = 0.01606mol