FROM REACTIONS TO EQUATIONS

In a chemical reaction, atoms must be conserved (a requirement of nature.) The conservation of matter is the underlying principle on which he writing of equations is based. Once you understand this principle, you will see why an equation that is correctly written must be a balanced equation.

OBJECTIVE: In this experiment, you will prepare three common gases, H2, O2, and CO2, through simple chemical reactions. Some characteristics of the three gases are compared and you will be required to write balanced equations to express the chemistry observed.

MATERIALS:

1M Hydrochloric acid (HCl)

3% Hydrogen Peroxide (H2O2)

Marble Chips (CaCO3)

Manganese Dioxide (MnO2)

Zinc, granular or mossy

Copper (II) Sulfate, Pentahydrate (CuSO4 • 5H2O)

Test Tubes

100 or 250 ml Beakers

Wood Splints

Goggles

Index Card

Pre-Lab:

In your lab notebook, please include the following:

a)Title Descriptive of the Lab Experiment

b)Purpose of the Lab: Why are you doing it? What do you hope to learn?

c)A detailed set of procedures. Please skip a line between each procedure.

** Please use the two-column format: The left column will contain your procedure; the right hand column will contain the observations made for that particular step. (See Example from a fictitious lab)

Procedures / Observations
1) Added KMNO4 to beaker / 1) Solution turned purple

PROCEDURES

  1. Preparing Hydrogen Gas
  1. Add approximately .5g of Zinc metal and two small crystals of Copper(II) sulfate to a clean, scratch free test tube.
  2. Place the tube upright in a test tube rack.
  3. Add 10 ml of Hydrochloric acid (labeled 1M HCl).
  4. LOOSELY cover the tube mouth by laying an index card over the top. **This step is VERY important!! (For safety reasons.)
  5. Wait several minutes for the generated gas to collect inside of the tube.
  6. Carefully bring a burning wood splint to the open mouth of the tube.
  7. Record your observations in the right hand column.
  1. Preparing Oxygen Gas
  1. Place approximately .5g of manganese dioxide (MnO2) in a clean test tube.
  2. Insert the tube into a test tube rack.
  3. Add 10 ml of 3% Hydrogen Peroxide (H2O2)
  4. Wait several minutes for the generated gas to collect in the tube.
  5. Light a wood splint; shake or blow it out so that the tip remains glowing.
  6. Insert the glowing splint in the tube.
  7. Record your observations in the right hand column.
  1. Preparing Carbon Dioxide Gas
  1. Place approximately five small marble chips in a test tube.
  2. Add 10 ml of Hydrochloric acid (HCl) to the test tube.
  3. Record your observations in the right hand column.
  4. Test the gas remaining in the test tube with a burning wood splint. Record your observations.

** BE SURE TO CLEAN ALL EQUIPMENT AND RETURN THEM TO THEIR APPROPRIATE STORAGE LOCATIONS. WASH HANDS THOROUGHLY. **REMEMBER – LEAVE YOUR WORK SPACE BETTER THAN YOU FOUND IT!!

From Reactions to Equations Post-lab Assignment

Please complete the following in your lab notebook:

  1. Write the balanced equation for the two reactions observed during part A of your lab experiment.

a)Zinc reacting with hydrochloric acid (HCl) to form hydrogen gas.

b)Hydrogen gas reacting explosively with oxygen gas to form water.

  1. Write the balanced equation for the reaction observed in Part B of the lab experiment.

a)Hydrogen peroxide being decomposed to form oxygen gas and water.

  1. Write balanced equations for the reaction observed during Part C of the lab experiment.

a)Calcium carbonate reacting with hydrochloric acid to produce carbon dioxide, calcium chloride, and water.

  1. Write a balanced equation for the burning of octane (C8H18) in air (O2) to form carbon dioxide and water. (A typical combustion reaction)
  1. Write a balanced equation for the formation of ammonia gas (NH3) from the combination of Hydrogen gas (H2) and nitrogen gas (N2).
  1. Write the balanced equation for the reaction of hydrazine (rocket fuel) N2H4, with dinitrogen tetroxide (N2O4) to form nitrogen gas (N2) and water.
  1. The overall chemical reaction involved in photosynthesis can be expressed in words: Carbon dioxide gas reacts with water to form glucose (C6H12O6) and oxygen gas (O2). Write a balanced equation for this reaction.
  1. Magnesium metal reacts with hydrochloric acid (HCl) to produce magnesium chloride and hydrogen gas. Write a balanced equation for this reaction.
  1. Write and balance each of the following equations in your notebook:

a) Fe2O3+C Fe+CO

b) Mg+O2MgO

c) Ca(CN)2+H2OCaCO3+NH3

d) NaI+Cl2NaCl+I2

e) Ca3(PO4)2+SiO2+CCaSiO3 +CO+ P4