A 140.5 g sample of niso4•xh2o was heated until no further mass decrease was noted. The remaining sample was assumed to be anhydrous niso4 with a mass of 77.5 g. First determine the moles of anhydrous niso4 and moles of h2o lost. What is the mole ratio of niso4 to water?

Question

Remington Simmons

Chemistry

11 July, 01:33

A 140.5 g sample of niso4•xh2o was heated until no further mass decrease was noted. The remaining sample was assumed to be anhydrous niso4 with a mass of 77.5 g. First determine the moles of anhydrous niso4 and moles of h2o lost. What is the mole ratio of niso4 to water?

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Eliana Gordon · Answer 1

moles of anhydrous nickel (II) sulfate salt = 0.908 mole

moles of water = 63/18 = 3.5 moles

The mole ratio of Nickel (II) Sulfate to Water = 1 : 4

Explanation:

mass of Nickel (II) sulfate hydrate = 140.5 grams

mass of Nickel (II) sulfate salt. = 77.5 grams

mass of water present in the hydrated Nickel salt can be calculated as : Mass of hydrated Nickel salt-mass of anhydrous salt

Therefore, mass of water = (140.5 - 77.5) = 63 grams

The moles of a substance is calculated as mass of substance/molar mass of substance

molar mass of water = 18 (Atomic mass of H=1*2=2g, O=16; 2+16=18g)

Thus moles of water = 63/18 = 3.5 moles

moles of Nickel (II) sulfate salt. = 140.5/154.69 (Molar mass of Nickel (II) sulfate is 154.75 i. e Ni = 58.69 + S = 32 + 0 = (16*4) = 64, Sum of atomic masses = 154.69

moles of anhydrous Nickel (II) sulfate salt = 0.908 mole

The mole ratio of Nickel (II) Sulfate to Water = 1 : 4