How many grams of H2 are needed to react with 2.15 g of N2?

Answer 1

It pays to write the correctly balanced chemical equation.

N₂ + 3H₂ ==> 2NH₃

moles N2 used = 2.15 g x 1 mol/28.0 g = 0.0768 moles

moles H₂ needed = 0.0768 mol N₂ x 3 moles H₂/mol N₂ = 0.230 moles H₂

mass of H₂ = 0.230 moles x 2.01 g/mol = 0.463 g H₂

Answer 2

Start with finding the molar masses of both H2 and N2. Since they are both diatomic (N2 has 2 atoms of N, H2 has 2 atoms of H) we will need to multiply the mass of H by 2 to find the mass of H2, for example.

If you look on the periodic table, you will see that H has a mass of 1.01 g. N has a mass of 14.01 g. That means H2 has a mass of (2 x 1.01g) = 2.02 g and N2 has a mass of (2x14.01g) = 28.02 g.

We would need a chemical reaction in order to figure out the answer to this question. It is likely that this problem is about the chemical formula for creating ammonia gas from nitrogen and hydrogen, which is:

H2 + N2 --> NH₃ Balancing this, we get 3H₂ + N₂ --> 2NH₃

Now, we have enough information, we just need to put it together.

2.15 g N₂ x (1 mol N₂/28.02 g N₂) x (3 mol H₂/1mol N₂) x (2.02 g H₂/1 mol H₂) = 0.46 g H₂

We use the information given plus ratios given in the problem to convert the mass of N2 to moles, convert moles of N2 to moles of H2, then use the molar mass of H2 to convert moles of H2 to mass of H2 for our final answer.

Answer 3

Let's assume the outcome of the combination will be ammonia. Ammonia's molecular formula is NH3 That means for every nitrogen atom we will need 3 hydrogen atoms.

Since nitrogen has an atomic mass of 14.0067 we have 0.153 (2.15/14.0067) moles of nitrogen. We will need 0.459 (3 times 0.153) moles of hydrogen to react completely.

Since hydrogen has an atomic mass of 1.0078 we will need 0.463 (1.0078 times 0.459) grams of hydrogen.