find the molar mass of 7.5gm of a gas occupying 5.8 lt volume at s.t.p.
To find the molar mass of a gas, we can use the ideal gas law equation:
PV = nRT
Where:
- P is the pressure of the gas (standard pressure is 1 atm at STP)
- V is the volume of the gas (5.8 L in this case)
- n is the number of moles of the gas (what we need to find)
- R is the ideal gas constant (0.0821 L·atm/(mol·K))
- T is the temperature of the gas (standard temperature is 0°C or 273.15 K at STP)
First, let's convert 7.5 g of the gas to moles using its molar mass. To find the molar mass, you will need to know the identity of the gas.
Let's assume the gas is carbon dioxide (CO2). The molar mass of CO2 is approximately 44 g/mol.
To convert grams to moles, divide the mass of the gas by its molar mass:
n = 7.5 g / 44 g/mol
Now, let's substitute the values into the ideal gas law equation:
(1 atm) * (5.8 L) = n * (0.0821 L·atm/(mol·K)) * (273.15 K)
Simplifying the equation, we get:
5.8 = n * 22.414
To solve for n, divide both sides of the equation by 22.414:
n = 5.8 / 22.414
Finally, calculate the value of n:
n ≈ 0.2587 mol
Therefore, the number of moles of the gas is approximately 0.2587 mol.
To find the molar mass, divide the mass of the gas by the number of moles:
Molar mass = mass / moles
Molar mass = 7.5 g / 0.2587 mol
Calculate this value to find the molar mass of the gas.
L is liters (or litres), not lt.
1 mole of a gas occupies 22.4 L at STP. So how many moles do you have? That's 5.8 L x (1 mol/22.4 L) = approx 0.25 but you need a more accurate answer than that. Then
mols = grams/molar mass. You have mols and grams, solve for molar mass.