A student repeats a reaction several times to test the effects of various changes on the reaction rate. The data table shows the results. How does
increasing the concentration of the reactants change the reaction rate?
5
Conditions
Reaction Time (5)
10 seconds
Original
Higher concentration
Higher temperature
5 seconds
5 seconds
Metal added
5 seconds
A. Increasing the concentration has no effect on the reaction rate.
B. Increasing the concentration decreases the reaction rate.
C. Increasing the concentration increases the reaction rate.
D. More information is needed to determine what happens to the
reaction rate.

The correct answer is - C.  Increasing the concentration increases the reaction rate.

Explanation:

In the given question the data with change in different factors affect the rate of reaction differently as it alters the time it takes to complete reaction:

Conditions                            Reaction Time

Original                                  10 seconds

Higher concentration            5 seconds

Higher temperature              5 seconds  

Metal added                           5 seconds

As it is given above, time is decreased in each condition including in the case of increasing the concentration of the reactants which means the rate of reaction increases as well.

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.