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Types of Chemical Reactions Quiz
Types of Chemical Reactions
Synthesis (Combination)
Single Replacement/Single Displacement
Double Replacement/Double Displacement
Oxidation (Combustion)

Chemical reactions are often classified into these five categories.

1a) 2KClO3 -->  2KCl  + 3O2

1b) MgSO4·7H2O --> MgSO4  + 7H2O

1c) N2 + 3H2 --> 2NH3

1d) C3H8 + O2 --> 3CO2 + 4H2O

1e) AgNO3 + NaCl --> AgCl + NaNO3

1f) 3C + Fe2O3 --> 2Fe + 3CO

1g) NH4I + Cl2 --> NH4Cl + I2

1h) C3H5(NO3)3 --> CO2+H2O+N2+O2

1i) Al + H2SO4 --> Al2(SO4)3 + H2

1j) H2SO4 + 2NaOH --> 2HOH + Na2SO4

Problem 1 (Types of reactions):

Look at the chemical reactions on the left. Identify what type of reaction is taking place (pick from list above).

Problem 2 (Decomposition): One reason medicines have an expiration date is that they start to decompose. Aspirin is one that will decompose especially if exposed to high humidity. You can tell if the aspirin has started decomposing by its smell. The reaction below starts with aspirin (acetyl salicylate) and then it shows the decomposition products of two molecules. What does the smaller molecule smell like? ... (Note: Turquoise spheres are carbon atoms, red spheres are oxygen atoms, and the small white ones are hydrogen atoms)
aspirin decomposes reaction

Problem 3 (more decomposition): Chemistry uses different ways to represent a chemical reaction. The AB -> A + B is a general way to express a decomposition reaction. Roll cursor over the image on the left to see an animation of a specific decomposition reaction. Write the chemical equation that matches this reaction. (If animation doesn't play right, you can try to click this link to see it in Flash format. Use back arrow to get back to quiz).

Problem 4 (Synthesis): Below is the synthesis of pear flavoring shown in the tutorial.
4a) How many carbon atoms does propyl alcohol have?
4b) How many oxygen atoms does acetic acid have?
4c) How many hydrogen atoms does the pear flavor have? (Note: its chemical name is propyl acetate)


1) CO2 + H2O --> H2CO3

2) H2CO3 --> H+ + HCO3-

Problem 5: Respiratory acidosis occurs when a person is not breathing out carbon dioxide fast enough (hypoventilation). This can be caused by breathing problems such as pneumothorax (collapsed lung), asthma (restricted airways), emphysema (nonelastic air sacs), pneumonia (mucus in lungs), or sedatives (slowed breathing). Carbon dioxide in the blood will produce acidic hydrogen ions (H+) in a two step process. That causes the blood to be more acidic than normal (acidosis). That's also called acidemia (acidic blood).
5a) Which of these steps (1 or 2) is a synthesis reaction?
5b) What is the name of H2CO3?
5c) What is the name of the HCO3- ion?

Problem: 6: Single replacement and sacrificial metal:
Most hot water heater tanks are made from steel (iron), which can corrode in the presence of oxygen and water. Here is the reaction.
2Fe + O2 + H2O --> 2Fe(OH)2
Each iron atom loses two electrons, which forms iron (II) hydroxide. A more reactive metal, such as magnesium (or zinc) can can sacrifice itself by giving iron its electrons and forming magnesium hydroxide (magnesium corrodes instead of iron). So the single replacement reaction looks like this:
Fe(OH)2 + Mg --> Mg(OH)2 + Fe
6a) Check your water heater and report if it has a sacrificial rod installed (nearly all do).
6b) What is the shape of the top of the rod (round, hexagonal/6 sided, octagonal/8sided, or something else)?
6c) You may see some corrosion around this rod in the form of a granular powder. If so, what is its color?

car exhaust vapor
condensation on beaker from car exhaust

Problem 7: Combustion reaction (a type of oxidation):
On cold mornings, you often see vapor coming from car exhausts. Even on warmer days, if you hold a beaker near the exhaust of a car whose engine has not warmed up, you can see condensation (bottom image). The combustion of gasoline produces (like all hydrocarbons) carbon dioxide and water. The average length of gasoline molecules is about 8 carbons long. So lets use octane to represent gasoline.
2C8H18 + 25O2 --> 16CO2 + 18H2O

Most people assume this vapor cloud is water vapor and the drops of liquid as just water; however, it's not just water. It's seltzer (carbonated) water. They forget that carbon dioxide is present and there has been a synthesis reaction.
CO2 + H2O --> ?

7a) Complete the above synthesis reaction.

7b) There's a small amount of sulfur in gasoline with some getting converted to SO3. It combines with water to form an acid. Complete this synthesis reaction:
SO3 + H2O -> ?

7c) What is the name of the acid that gets produced?

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Since April 6, 2009