A sample of nickel was dissolved in nitric acid to produce a solution with a volume of 50.00 mL - HSC - SSCE Chemistry - Question 14 - 2021 - Paper 1

Using the concentration calculated above and the total volume of the diluted solution:

$\text{Number of moles} = ext{Concentration} \times ext{Volume} = 0.0015 \, \text{mol L}^{-1} \times 0.250 \, \text{L} = 0.000375 \, \text{mol}$

To find the mass of nickel, use the molar mass of nickel (approximately 58.69 g/mol):

$\text{Mass} = \text{Number of moles} \times \text{Molar mass} = 0.000375 \, \text{mol} \times 58.69 \, \text{g/mol} \approx 0.022 \, \text{g}$

Next, consider the dilution factor:

The original solution was 10.00 mL, which was diluted to 250.0 mL, leading to a dilution factor of:

$\text{Dilution Factor} = \frac{250.0 \, \text{mL}}{10.0 \, \text{mL}} = 25$

Thus, the mass of nickel in the original sample is:

$\text{Mass}_{\text{original}} = 0.022 \, \text{g} \times 25 = 0.55 \, \text{g}$

Considering the options available, the closest value is:

D. 0.15 g.