Calcium Lab

Table 2: Observations During Reaction #1

Table 3: Quantitative Observations after Reaction #1

Table 4: Observations of Reaction #2

Table 5: Observations of the Product of Reaction #2

Questions

1) What safety precautions were required for this experiment? Explain your reasoning.
    Although this experiment was not very dangerous, there were still some safety requirements. First of all, we put safety goggles to protect our face not necessarily from explosions, but to ensure our complete safety at all times, in case a substance, say, the product of hydrochloric acid and calcium carbonate were to go in our eyes.

2) How do you know a gas was evolved in reaction 1? Provide evidence. What was it?

When hydrochloric acid was added to calcium carbonate, bubbles appeared and which is a sign that a gas is formed because. Also, in the first equation, one of the products is carbon dioxide.

3) If 2.00g of CaCO3 was used, how many salt molecules did you dump down the sink?

4) What volume of 5.0 mol dm^(-3) hydrochloric acid will be required in order to react with 2.00g of calcium carbonate?

5) Calculate the % yield for CaCO3. 

Sources of Error

The container of calcium carbonate was left opened, without the lid, for an unknown period of time. It is highly likely that water or other interfering unknown molecules may have entered the container and may have changed the calcium carbonate into something less pure. After reaction both reactions were finished, we filtered the liquids from the solids. While we filtered, there is a possibility that the filter paper could have ripped a little and this would have caused some of the solid to be filtered. As a result, the mass of calcium carbonate may be a little bit off.  Other errors include the fact that not all reactants may have reacted due to some unknown random error and that not all reactants retrieved from the containers are 100% pure.

Conclusion

        In this experiment, we learned how to calculate the percent yield by using the formulas of the reactions to first calculate the expected amount of product. When we reacted 2g of calcium carbonate, our result was 1.84 g. The expected yield was 2 g, and so we were both very close to the expected yield, as our percent yield for CaCO3 is 91%. In this experiment, we learned that it is not easy to get a high percent yield, and that exact measurements are crucial when conducting an experiment. To decrease the possibility of errors to the best of our ability, we must have the most exact measurements as possible.