Final answer:
To find the amount of hydrogen in pure water, convert 79.2 gallons to grams and multiply by 11.2% (hydrogen's mass ratio in water), which yields a much larger amount than the options given. It's likely there is a typo in the given facts, and the student may need to confirm the correct values.
Step-by-step explanation:
To calculate approximately how much hydrogen is in 79.2 gallons of pure water, we use the fact that pure water consists of 11.2% hydrogen by mass. The question provides that each gram of water contains 0.111 gallons of hydrogen, which seems inconsistent with the percentage mentioned, so we'll base our calculation on the percentage instead. First, we need to convert gallons of water to grams, understanding that 1 gallon of water weighs approximately 3785.41 grams. Then we'll calculate 11.2% of that mass to find the mass of hydrogen.
79.2 gallons of water × 3785.41 grams/gallon = 299882.752 grams of water
299882.752 grams of water × 11.2% (0.112) = 33586.868 kilograms of hydrogen (approximately)
Since the option must be in grams and all the options provided are below 1000 grams, there might be a misunderstanding in the question. A possible error could be in the initial fact provided - instead of 0.111 gallons of hydrogen per gram of water, it might be more reasonable to infer that it should be 0.111 grams of hydrogen per gallon of water, which aligns with the 11.2% mass composition of hydrogen in water.
79.2 gallons of water × 0.111 grams/gallon = approximately 8.792 grams of hydrogen
Since this result does not align with the provided options either, and considering the initial information might contain a typo, the student may need to check the validity of the initial facts or the question may be missing some information.