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Subject Test Chemistry

Question 3 of 17

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Each of the questions or incomplete statements below is followed by five suggested answers or completions.  Select the one that is best in each case.

text ... Cu end text to the power of 2 plus end exponent left parenthesis a q right parenthesis plus text   end text... invisible times text    I end text to the power of minus left parenthesis a q right parenthesis rightwards arrow text   end text... invisible times text    CuI end text left parenthesis s right parenthesis plus... invisible times text    I end text subscript 2 left parenthesis s right parenthesis

When the equation above is balanced and all coefficients are reduced to lowest whole-number terms, the coefficient for text I end text text end text to the power of minus end exponent left parenthesis a q right parenthesis is

Select an Answer

1

Correct Answer: 
No

2

Correct Answer: 
No

3

Correct Answer: 
No

4

Correct Answer: 
Yes

5

Correct Answer: 
No

This question pertains to the balancing of chemical equations. To answer this question correctly, you need to recognize that both mass and charge must be conserved in any chemical equation. With this in mind, the chemical equation is correctly written as

2 text Cu end text text end text to the power of 2 plus end exponent left parenthesis a q right parenthesis text + 4 I end text text end text to the power of minus end exponent left parenthesis a q right parenthesis rightwards arrow 2 text end text text CuI end text left parenthesis s right parenthesis text + I end text text end text subscript 2 end subscript left parenthesis s right parenthesis

The coefficient for text I end text text end text to the power of minus end exponent left parenthesis a q right parenthesis is 4.

Question Difficulty: 
easy