If it takes 15 s for a certain sample of neon to effuse through a porous barrier, how much time will it take for the same amount of nitrogen gas to effuse through the barrier under the same conditions? 1. greater than 15 s 2. less than 15 s 3. 15 s

The correct answer is;

2. less than 15 s

Explanation:

Grahams law of effusion states

Therefore

we have molar mass of neon gas = 20.18 g/mol

Molar mass of nitrogen gas = 28.014 g/mol

Which gives

= 0.72

Therefore the rate of effusion of nitrogen gas is 0.72*15 = 12.73 s which is less than 15 s

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.