How many grams of n2 are required to make 75 grams of nh3?

2.138 I think

Explanation:

N2 + 3H2 -> 2NH3

This means that 3 moles of H2 gives 2 moles of NH3

Lets convert 12.12 g of NH3 into moles.

The molecular weight of NH3 is 17 g/mol

So 12.12 g is 0.713 moles

If 2 NH3 comes from 3 moles of H2

1 mole comes from 1.5 moles of H2

So 0.713 moles of NH3 comes from 1.5 x 0.713 moles of H2 =1.069 moles of H2

1 mole of H2 weights 2g

So 1.069 moles of H2 weighs 2.138 g

the answer to your question is c

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.