Question

Copper(I) iodide (CuI) is often added to table salt as a dietary source of iodine. How many moles of CuI are contained in 1.00 lb (454 g) of table salt containing 0.0100% CuI by mass?

a) 2.28 x 10⁻⁴ mol
b) 4.56 x 10⁻⁴ mol
c) 1.14 x 10⁻³ mol
d) 2.28 x 10⁻³ mol

Answer 1

By calculating 0.0100% of 454 g to find the mass of CuI and dividing this by the molar mass of CuI, we determine there are 2.28 x 10^-4 moles of CuI in the table salt sample.

Step-by-step explanation:

To calculate the number of moles of CuI in the sample, we first need to determine the mass of CuI in the table salt. Given that there is 0.0100% CuI by mass, we calculate the mass of CuI in 454 g of table salt:

0.0100% of 454 g = 0.0100/100 × 454 g = 0.0454 g CuI

Now, we use the molar mass of CuI to find the number of moles. The molar mass of CuI is 63.55 g/mol (Cu) + 126.90 g/mol (I) = 190.45 g/mol.

Using the formula:

number of moles = mass (g) ÷ molar mass (g/mol)

number of moles of CuI = 0.0454 g ÷ 190.45 g/mol

The calculation gives:

number of moles of CuI = 2.38 × 10-4 mol

The correct choice based on the options is:

(a) 2.28 x 10-4 mol