Question

Water is produced from the reaction of hydrogen and oxygen gas, according to the equation below. What is the excess reactant in the reaction of 4.2 moles of hydrogen with 3.0 moles of oxygen?

2H2(g) + O2(g) = 2H2O(L)

Select one:
a. Water
b. Oxygen
c. No excess reactant
d. Hydrogen

Answer 1

Answer:

b. Oxygen

Explanation:

It can be seen that the chemical equation have 2 moles of hydrogen gas that should be reacted with the one mole of oxygen gas

Now for 4.2 moles, the hydrogen gas would be reacted as

= 4.2 × 1 ÷  2

= 2.1 mole oxygen gas

Therefore the hydrogen would be limited the reagent because it limits the product formation

On the other hand, the oxygen is the excess reagent i.e.

= 3 - 2.1

= 0.9 moles

This would be left for oxygen

Hence, the correct option is b.