Question

A student standardized a sodium thiosulphate solution. The student used 0.9442 g  of potassium iodate to prepare 250.0 mL of a standard solution. When 25.00 mL aliquots of the standard solution were titrated, the average titre required was 25.87 m. A copper unknown was analyzed using the standardized Na₂S₂O₃. The unknown copper sample weighed 3.9498 g and was dissolved in deionized water and made up to a volume of 250.0 mL. 15.24 mL of the standardized Na₂S₂O₃ (from the earlier question) was required to titrate 25.00 mL of the unknown copper solution.

How many moles of I₂ did the Na₂S₂O₃ react with?
How many moles of Cu(NO₃)₂ were in the 25.00 mL sample used in the titration reaction? grams?
What was the mass (grams) of Cu(NO₃)₂ ·x H₂O (the unknown solid) that was present in the 25.00 mL sample.
What was the mass of H₂O that was present in the Cu(NO₃)₂ ·x H₂O sample being analyzed?
How many moles of H₂O were present in the Cu(NO₃)₂ ·x H₂O used in the 25.00 mL sample?
What is the stoichiometric value for x in Cu(NO₃)₂ ·x H₂O ? (to the nearest whole- or half-integer).

3moles of iodine are produced by 1 mole of iodate.
2 moles of thiosulphate are required to react with 1 mole of iodine
molar mass of KIO3: 214.00
moles of KIO₃ are weighed out: 0.00441
molarity of the standard KIO3 solution: 0.01764
moles of KIO₃ are in 25.00 mL of standard solution: 0.00441
moles of iodine were produced by the iodate: 0.001325
moles of Na₂S₂O₃ were required in the titration to react with the I₂ produce from the 25.00 mL aliquot of KIO₃ : 0.002646
molarity of the Na₂S₂O₃ solution that was standardized: 0.1023
moles of Na₂S₂O₃ were used in the titration: 0.00156
moles of Cu²⁺ were required to produce the I2: 0.00156
molar mass (grams/mole) of Cu(NO3)2: 187.56
molar mass H2O: 18.02

This is all the information I have.

Answer 1