Answer:
32.8g/mole
Explanation:
Given parameters:
Mass of sample of gas = 32.8g
Volume = 22.4L
Unknown:
Molecular weight = ?
Solution:
To solve this problem we must understand that at rtp;
1 mole of gas occupies a volume of 22.4L
Number of mole of the gas = 1 mole
Now;
Mass = number of moles x molecular weight
molecular weight = =
= 32.8g/mole
The molar mass of the carbohydrate : = 304.19 g/mol
<h3>Further explanation</h3>Given
6.54 g carbohydrate
102.5 g of water
osmotic pressure of 4.61 atm
T = 20+273=293 K
Required
The molar mass
Solution
General formula:
π = osmosis pressure (atm)
M = solution concentration (mol / l)
R = constant = 0.08205 L atm mol-1 K-1
T = Temperature (Kelvin)
Find molarity(M) :
4.61 atm = M . 0.08205 x 293
M = 0.192 mol/L(mol solute per 1 liter solution)
Total mass of solution :
= 6.54 g + 102.5
= 109.04 g
Volume of solution :
= density x mass
= 1.024 g/ml x 109.04 g
= 111.66 ml
= 0.112 L
mol Carbohydrate (solute):
= M x V
= 0.192 x 0.112
= 0.0215 mol
Molar mass of Carbohydrate :
= mass : mol
= 6.54 : 0.0215
= 304.19 g/mol