Chemical Reactions Lab

6-3: This process is used by cells to manufacture _biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products__

3. Carefully felt the sides of the test tube and observed the resulted chemical reaction for about 30 seconds.

In experiment A the results from the precipitation of CaC2O4 H2O from the salt mixture were obtained by weighing the items listed on Table 1 on a scale.

These reactions can be seen from just a little bit of reaction all the way up to a complete change of the entire sample tested. Some samples of those tested in this experiment which showed the chemical reaction were the baking soda/ammonia mixture, the Epson salt and baking soda mixture as well as the food coloring mixed with the baking soda and bleach. 2. Which reactions, if any, do you believe showed no evidence of chemical change? Justify your reasoning.

In the last test, we had to test out a mystery powder (powder A, B, C), in its own separate test tube, in order to solve the Sherlock Holmes Mystery. Our group had powder C. When we mixed water in the mystery powder, it did not dissolve. When the litmus paper was put into the test tube it turned blue. When the vinegar was mixed it bubbled/foamed up. When we mixed the iodine solution, there was no reaction and the solution turned to a dark brown/black color. When we mixed in the baking soda there was no reaction and it turned to an even darker color.

The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.

5. Was there any evidence that some of the copper (II) chloride was left in the beaker? Explain.

A chemical reaction is when substances (reactants) change into other substances (products). The five general types of chemical reactions are synthesis (also known as direct combination), decomposition, single replacement (also known as single displacement), double replacement (also known as double displacement), and combustion. In this lab, the five general types of chemical reactions were conducted and observations were taken before, during, and after the reaction. Then the reactants and observations were used to determine the products to form a balanced chemical equation. The purpose of this lab was to learn and answer the question: How can observations be used to determine the identity of substances produced in a chemical reaction?

Substances A and B have an appearance of a white solid like. Substances A and B were put into a test tube and on the Bunsen burner. As a result, B melted faster than A. A was slow to melt. The reason why B melted faster than A is because it has a lower boiling point than substance A which made it melt faster. It also shows that A needs more energy than B to be broken down.

Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.

In the first part of the experiment (identifying the chemical makeup of the unknown compound

1. What type of macroscopic evidence for chemical change did you observe during this experiment? Give at least three different examples.

Many signs show that a chemical reaction has occurred. Some ways we know there is a chemical reaction are the formation of gas, formation of precipitate, change in temperature, and,or change in color. In part one of the experiment, we know there was a chemical change because of the formation of the white precipitate. We poured the ammonia and water in the flask with alum and water, forming a white, cloudy substance in between the two liquids. The white, cloudy substance between the two is liquids is also known as aluminum hydroxide. The second part of the experiment was very similar to the first, but in the second part we mixed epon salt, water, and ammonia. The precipitate formed from mixing the epson salt, water, and ammonia was called magnesium hydroxide.

This was determined by observing significant reactions that occurred when the powders that Unknown Mixture #2 consisted of were individually tested with the liquid reagents. Alka-seltzer proved to be a highly reactive reagent as bubbling occurred whenever any of the liquid reagents were mixed with it. It appears that alka-seltzer created a neutralization reaction with each of the liquids. Since alka-seltzer and baking soda contain similar chemical properties, it can also be inferred that the bubbles that were apparent for each of these neutralization reactions was the gaseous carbon dioxide that was created during the reaction. While alka-seltzer seemed to be highly reactive, table salt wasn’t very reactive at all. Despite the fact that salt wasn’t very reactive, it can still be deduced that salt was in Unknown Mixture #2 without noticing any of its reactions. This is because it is already evident that baking soda and cornstarch are in Unknown Mixture #1. Since two of the four possible substances are already in Unknown Mixture #1 and none of their special properties were observed in Unknown Mixture #2, the presence of salt in Unknown Mixture #2 can be confirmed by using the process of elimination. By understanding how each of the powders reacts with each of the liquid regents, the substances of the unknown mixtures can be

Purpose: The purpose of this experiment was to observe the many physical and chemical properties of copper as it undergoes a series of chemical reactions. Throughout this process, one would also need to acknowledge that even though the law of conservation of matter/mass suggests that one should expect to recover the same amount of copper as one started with, inevitable sources of error alter the results and produce different outcomes. The possible sources of error that led to a gain or loss in copper are demonstrated in the calculation of percent yield (percent yield= (actual yield/theoretical yield) x 100.