Question

A.Given the balanced chemical equation 2H2O2 -> 2H2O + O2
How many moles of reactant are required to produce 0.200 moles of O2?

B.If 12.5 g of H2O2 are reacted to produce 5.38 g of O2 how many grams of water were produced?

Answer 1

This problem asks for the moles of hydrogen peroxide needed to produce 0.200 moles of O2 and the mass of water produced by 12.5 g of hydrogen peroxide. Answers turn out to be 0.400 mol and 7.1 g.

Stoichiometry

In chemistry, stoichiometry is a tool for us to perform moles-mass relationships in balanced chemical reactions via proportional factors including both molar masses and mole ratios.

Thus, for part A, we can simply apply the 2:1 mole ratio of hydrogen peroxide to oxygen so as to calculate the moles of the former producing 0.200 moles of the latter as shown below:

$0.200molO_2*\frac{2molH_2O_2}{1molO_2}=0.400molH_2O_2$

Then, for part B we must use the law of conservation of mass which states that the mass of reactants must be equal to that of products at the end of the reaction (matter is neither created nor destroyed). In such a way, we can proceed as follows:

$m_{H_2O_2}=m_{H_2O}+m_{O_2}\\\\12.5g=m_{H_2O}+5.38g\\\\m_{H_2O}=12.5g-5.38g\\\\m_{H_2O}=7.1g$

Learn more about stoichiometry: brainly.com/question/9743981