Question

One lab group skipped Part I, step 1, and forgot to dissolve an Alka-Selzer tablet in the water for the tank. Will their results be affected? If so, will the reported percent CaCO3 in the original sample be higher or lower than the true value? Explain your answer.

Options:
a) Yes, higher
b) Yes, lower
c) No, higher
d) No, lower

Answer 1

Yes, the results will be affected. When the Alka-Selzer tablet is dissolved in water, it reacts to produce carbon dioxide gas, which is important for the experiment. The reported percent CaCO₃ in the original sample will be lower than the true value.

Step-by-step explanation:

Yes, the results will be affected. When the Alka-Selzer tablet is dissolved in water, it reacts to produce carbon dioxide gas, which is important for the experiment. The reaction is as follows:

H₂O + CO₂ → H₂CO₃

The carbonic acid (H₂CO₃) that forms helps dissolve the CaCO₃ present in the original sample, allowing it to be measured. Without the tablet, there will be less carbon dioxide and therefore less dissolution of CaCO₃. As a result, the reported percent CaCO₃ in the original sample will be lower than the true value.