Calculate the mass, in grams, of 0.245 moles of nickel (11) perchlorate

38.7 g

Explanation:

first you find the molar mass of Nickle (II) Perchlorate

Nickle = 58.693 g/mol

Perchlorate is Chlorine and Oxygen combined

Molar mass of chlorine is 35.453 g/mol

Oxygen = 15.999 g/mol but since it has 4 oxygen atoms combined with chlorine you have to multiply 15.999 by 4 which is 63.996 add all the masses together and that gives you 158.142. Since you have moles you multiply the moles by the molar mass which looks like this. 0.245 * 158.142 which equals 38.74479 but with sign figs it is 38.7g as your final answer. Ask me if you are confused about something.