A student claims that the reaction of hydrogen and oxygen to form hydrogen peroxide is evidence supporting the claim that mass is conserved in a reaction. The chemical equation the student uses for the reaction is shown. Does this evidence support the claim? Why or why not? H2 + O2 → H2O2 ○ No, it does not support the claim because more oxygen is necessary. ○ Yes, it supports the claim because the equation is balanced. ○ No, it does not support the claim because more hydrogen is necessary. ○ Yes, it supports the claim because the mass before and after is the same.

4.69 The pictures below show a molecular-scale view of a chemical reaction between H2 and CO to produce methanol, CH3OH. The box on the left represents the reactants at the instant of mixing, and the box on the right shows what is left once the reaction has gone to completion. Was there a limiting reactant in this reaction? If so, what was it? Write a balanced chemical equation for this reaction. As usual, your equation should use the smallest possible whole number coefficients for all substances.

Many cereals are made with high moisture content so that the cereal can be formed into various shapes before it is dried. A cereal product containing 58% H2O by mass is produced at the rate of 1000. kg/h. What mass of water must be evaporated per hour if the final product contains only 20.% water?

4.68 The pictures below show a molecular-scale view of a chemical reaction between the compounds AB2 and B2. (Green balls represent B atoms and orange balls are A atoms). The box on the left represents the reactants at the instant of mixing, and the box on the right shows what is left once the reaction has gone to completion. Was there a limiting reactant in this reaction? If so, what was it? Write a balanced chemical equation for this reaction. As usual, your equation should use the smallest possible whole number coefficients for all substances.