Chemistry 20 Lab 0 – Types of Reactions



Chemistry 20 Review – Types of Reactions

In this lab, you will investigate three of the 5 types of chemical reactions we have learned about. There are three parts to the lab, Part A, B and C. You will start on the part designated by the LD, then switch when told.

Parts of a Lab Report: Your lab report will contain some or all of these headings:

Problem – tells you why you are doing the lab. The problem is to be solved in the conclusion of the lab.

Hypothesis - a prediction you make about the outcome of the lab. Written as a sentence in the third person. To be either confirmed or refuted in the conclusion.

Materials – a list of what you will need to perform the lab.

Experimental Design – tells you how the lab will be set up. May include diagrams of any apparatus needed.

Procedure – a list of steps needed to perform the lab. You will often write these steps yourself before you get into the lab.

Observations – a table or chart is used to collect observations you make during the lab.

Analysis – a section for performing calculations and/or answering additional questions posed by the LD.

Conclusion – answers the problem initially posed. Tells the reader whether the hypothesis was correct or not and why. THE MOST IMPORTANT PART OF THE LAB REPORT!

Note: In order to complete the lab in the time allowed, you should complete as much of this lab report before class.

Part A – Simple Composition Reaction

Problem: What are the properties of the compound produced by the reaction of magnesium burning in air?

Materials:

Mg(s) ribbon tongs

beaker Butane Burner

water

Procedure:

1. Using tongs, hold a small (2-3 cm) section of magnesium ribbon in the flame.

2. Hold the burning magnesium in the beaker to collect a sample of the burnt product.

3. Observe the product. Note its colour, phase, texture and solubility.

CAUTION: AVOID LOOKING DIRECTLY AT BURNING MAGNESIUM!

Observations:

| |colour |phase |texture |solubility in water |

|Before (Mg(s)) | | | | |

|After (?) | | | | |

Analysis:

1. What evidence was observed to indicate that a chemical reaction occurred?

2. Write the balanced chemical equation for the observed chemical reaction.

3. Name the product formed in this reaction.

4. Suggest another possible chemical reaction that might be occurring in this experiment. Write a balanced equation for this reaction.

Part B – Single Replacement Reaction

Problem: What products form when calcium metal is added to water?

Materials:

water matches

Ca(s) pH paper

2 test tubes scoopula

Hypothesis: Write a balanced equation for the reaction you expect to occur.

Procedure:

1. Fill the test tube half full with tap water.

2. Add a pinch of calcium metal to a test tube. Quickly place the other test-tube overtop to collect any gas that may be formed. Keep the second tube inverted.

3. Perform any diagnostic tests to determine the products (hint: see appendix).

CAUTION: AVIOD SKIN CONTACT WITH BOTH PRODUCTS AND REACTANTS.

Observations:

1. Describe any products observed being formed.

2. Describe the results of any diagnostic tests performed.

Conclusion:

What were the products of this reaction? Give qualitative evidence to support your claim.

Part C – Double Replacement Reaction

Problem: What properties are formed when the given aqueous ionic compounds are mixed.

Hypothesis: Make a prediction based on the generalizations you have learned about double replacement reactions towards the identity of the products of this reaction.

Materials:

either aqueous calcium chloride and aqueous sodium carbonate

or aqueous nickel (II) nitrate and aqueous sodium hydroxide

2 test tubes filter funnel

ring stand filter paper

utility clamp glass rod

50 ml beaker

Experimental Design:

The two aqueous ionic compounds provided will be mixed together in one of the test tubes and the properties of any products formed will be described. Any insoluble products that precipitate are to be separated from the reaction mixture by filtration.

Procedure:

Write a step-by-step procedure for this experiment.

Observations:

Design a means of reporting the observations to be recorded in this experiment (table, chart, etc).

Analysis:

1. Write a balanced equation for the reaction observed (use your solubility table to verify the identity of any insoluble products).

Conclusion:

Appendix

Part A

Turn off the butane burner between uses, the fuel is expensive. Be careful with the flame!

Dispose of the excess product in the beaker provided.

Part B

pH paper turns red in the presence of acids, blue in the presence of bases.

Compounds containing H are often acids.

Compounds containing the hydroxide ion, OH-, are often bases.

Hydrogen gas is flammable.

Dispose of the excess products in the waste container provided.

Part C

You can determine which product is the precipitate (the one which appears after the reaction) by looking for the solid in your balanced chemical equation (on the products side).

*Important notes

- The words “I, we, my, our” i.e. first person terms, never appear in a lab report. Each first person term found results in a 1-mark deduction.

- The conclusion and hypothesis must be written in complete sentences.

- The entire report must be neat and organized! Take some pride in your work.

Safety

*Avoid skin contact with all chemicals. Nothing is particularly harmful, if you do spill any on your skin, wash it off immediately. Students should wash his or her hands after the lab.

*Looking directly into burning magnesium can cause a “welders flash” like reaction. This hurts, so look away please!

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Name: ____________

Date: ____________

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