Ammonia is produced by the following reaction.

3h2(g) + n2(g) > 2nh3(g)

when 7.00 g of hydrogen react with 70.0 g of nitrogen, hydrogen is considered the limiting reactant because
7.5 mol of hydrogen would be needed to consume the available nitrogen.
7.5 mol of nitrogen would be needed to consume the available hydrogen.
hydrogen would produce 7.5 mol more ammonia than nitrogen.
nitrogen would produce 7.5 mol more ammonia than hydrogen.

The correct statement is 7.5 mol of hydrogen would be needed to consume the available nitrogen.

Explanation:

To calculate the number of moles, we use the equation:  

Given mass = 7 grams

Molar mass = 2 g/mol

Putting values in above equation:

Given mass = 70 grams

Molar mass = 28 g/mol

Putting values in above equation:

By Stoichiometry of the reaction:

1 mole of nitrogen is consumed by 3 moles of hydrogen

2.5 moles of nitrogen is consumed by = of nitrogen gas.

Hydrogen is considered as a limiting reagent because it limits the formation of products and will be totally consumed by a less quantity of excess reagent.

Hence, the correct statement is 7.5 mol of hydrogen would be needed to consume the available nitrogen.

nuclear fission produces elements that are heavier than helium.

the elements that are used in nuclear fission and their products are much heavier than helium.