Two moles of nitrogen gas at stp has (i) a density of 0.625 g/ l (a) only i is correc t (ii) a volume of 44.8 l (b) only ii is correct (iii) a mass of 28 g (c) i and ii are correct (d) ii and iii are correct (e) i, ii, and iii are correct

b. Only II is correct

Explanation:

Remember that STP means that the temperature is 273 K and the pressure is 101.3 KPa.

Density is an intensive property, that mean that does not depend on the quantity of substance, so if you have 1 mole or 2 is the same. Density of N2 is 1.25 g/L.

The mass of 1 mole of N2 is 28 g, but in this case you have 2 moles, that means the double of grams, that is the reason, why is incorrect this option.

3

explanation:

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"