Predicting chemical reactions

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Question 16
Medium

Group 7 elements (halogens) react with halides in solution.

Bromine reacts with potassium iodide to form potassium bromide and iodine.

Br2(aq)+2KI(aq)→2KBr(aq)+I2(aq)\text{Br}_2(\text{aq}) + 2\text{KI}(\text{aq}) \rightarrow 2\text{KBr}(\text{aq}) + \text{I}_2(\text{aq})Br2​(aq)+2KI(aq)→2KBr(aq)+I2​(aq)

a.

Describe what you would observe in the reaction.

[1]
b.

This is the half equation that shows what happens to bromine. Br2+2e−→2Br−\text{Br}_2 + 2\text{e}^- \rightarrow 2\text{Br}^-Br2​+2e−→2Br− Explain why this half equation shows reduction.

[1]
c.

Write the balanced half equation for the reaction of the iodide ions.

[1]
d.

Bromine displaces iodine from potassium iodide because bromine is more reactive than iodine. Explain why bromine is more reactive than iodine.

[3]
e.

The diagram shows the mass spectrum for a compound containing bromine.

A mass spectrum graph of a compound containing bromine. The x-axis is labeled 'Mass to charge ratio' with a scale ranging from 80 to 100, with ticks at every unit. The y-axis is labeled 'Relative abundance' and ranges from 0 to 100. There are two major peaks at high mass-to-charge ratios: a peak at 94 with a relative abundance of 100, and a peak at 96 with a relative abundance of 98.

State the relative molecular mass of the heavier molecular ion of this compound.

[1]
f.

Instrumental methods of analysis, such as mass spectrometry, have advantages over simple chemical methods of analysis. State two advantages of instrumental methods of analysis.

[2]

Predicting chemical reactions Questions

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