To determine the grams of aluminum oxide formed, we need to consider the balanced chemical equation for the reaction between aluminum and oxygen. The molar ratio between aluminum and aluminum oxide is 4:2. So, first calculate the moles of aluminum in 1020g, then use this to find the moles of aluminum oxide produced, and finally convert moles of aluminum oxide to grams.
To find the fraction of 1kg and 20g, you first need to convert both to the same unit. Since 1kg = 1000g, the total weight is 1020g. So, the fraction would be 20g / 1020g = 1/51.
When hydrated copper sulfate is heated, it loses its water molecules to form anhydrous copper sulfate. Since the molar ratio between the two forms is 1:1, if 6.4 moles of hydrated copper sulfate is heated, 6.4 moles of anhydrous copper sulfate will be produced.