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Transition elements

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Question 12

A complex compound of chromium, Y, has the formula K[Cr(NCS)x(NH3)y]\text{K}[\text{Cr}(\text{NCS})_x(\text{NH}_3)_y]K[Cr(NCS)x​(NH3​)y​] and contains NCS−\text{NCS}^-NCS− and NH3\text{NH}_3NH3​ ligands.

The percentage by mass of three of the elements in compound Y is shown below:

  • Cr\text{Cr}Cr: 14.54%
  • S\text{S}S: 35.91%
  • N\text{N}N: 23.49%

Use the following molar masses: Cr=52.0 g mol−1\text{Cr} = 52.0\text{ g mol}^{-1}Cr=52.0 g mol−1, S=32.1 g mol−1\text{S} = 32.1\text{ g mol}^{-1}S=32.1 g mol−1, and N=14.0 g mol−1\text{N} = 14.0\text{ g mol}^{-1}N=14.0 g mol−1.

a.

Calculate the values of xxx and yyy in the formula of compound Y.

[4]
b.

Determine the oxidation number of chromium in compound Y.

[2]

Transition elements Questions

  1. A Level
  2. /Chemistry
  3. /Transition elements