2 litres of nitrogen at N.T.P. weighs __________ gms.

ANS:B - 2.5

To find the weight of 2 liters of nitrogen at N.T.P. (Normal Temperature and Pressure), we first need to calculate the number of moles of nitrogen using the ideal gas law: 𝑃𝑉=𝑛𝑅𝑇PV=nRT Where:

• 𝑃P is the pressure (at N.T.P., it's approximately 1 atm)
• 𝑉V is the volume (2 liters)
• 𝑛n is the number of moles
• 𝑅R is the gas constant (approximately 0.0821 atm L/mol K)
• 𝑇T is the temperature (at N.T.P., it's approximately 273 K)

Substituting the given values: (1 atm)×(2 liters)=𝑛×(0.0821 atm L/mol K)×(273 K)(1atm)×(2liters)=n×(0.0821atmL/mol K)×(273K) 2 atm L=𝑛×(22.41 L atm mol−1)2atmL=n×(22.41Latmmol−1) 𝑛=222.41 moln=22.412​mol 𝑛≈0.089 moln≈0.089mol Now, to find the weight of nitrogen, we use its molar mass, which is approximately 28 g/mol: Weight=𝑛×Molar massWeight=n×Molar mass Weight=0.089 mol×28 g/molWeight=0.089mol×28g/mol Weight≈2.5 gWeight≈2.5g Therefore, 2 liters of nitrogen at N.T.P. weighs approximately 2.5 grams.