A student investigates whether dissolving calcium carbonate ( ) in excess…

CHEMISTRY · Multi-part · AP · Chemistry · Chemical Reactions · Chemical Reactions

Problem

A student investigates whether dissolving calcium carbonate (

1.00\,\text{g}

) in excess hydrochloric acid is a physical or a chemical change. The reaction is carried out in an open beaker placed on a balance that records the mass of the entire setup every

30\,\text{s}

for

5\,\text{min}

. A simplified data table is reproduced below.

Time (s)	Recorded mass (g)
0	120.00
30	119.80
60	119.65
90	119.60
120	119.60

(The mass readings remain constant at

119.60\,\text{g}

for the remainder of the

5\,\text{min}

interval.) (a) Calculate the total change in mass of the system between

t=0\,\text{s}

and

t=120\,\text{s}

. (b) Identify the specific macroscopic evidence in the experiment that suggests a chemical change rather than a physical change. (c) Using both your calculation from part (a) and the experimental observation from part (b), justify whether dissolving calcium carbonate in hydrochloric acid should be classified as a physical change or a chemical change.

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