Chemical Reactions

Which one of the following is not a physical change?
1. Making toast
2. Melting chocolate
3. Cutting a page in half
4. Mixing salt and pepper
Which one of the following is not a chemical change?
1. Grating cheese
2. Baking a cake
3. Rusting of a nail
4. Burning coal
A process that involves heat being given out, is called
1. an exothermic process
2. an endothermic process
3. a chemical reaction
4. a physical reaction
A process that involves heat being taken in is called
1. an endothermic process
2. an exothermic process
3. a chemical reaction
4. a physical change
Steam condensing on cold tiles is an example of
1. an exothermic process
2. an endothermic process
3. a chemical change
A student placed a thermometer in a test tube half-filled with water.
She the added a spatula of ammonium chloride to the test tube and observed the temperature decrease. This is an example of
1. an endothermic reaction
2. an exothermic reaction
3. condensation
4. evaporation
Which one of the following is not true for a chemical reaction
1. It can easily be reversed.
2. A completely new substance is formed.
3. It involves a change in energy.
4. Heat is usually involved.
Rusting is a serious problem with metal structures.
Which one of the following is NOT a condition necessary for rusting?
1. Heat
2. Moisture
3. Oxygen
In a chemical reaction, the substances that react together are called
1. the reactants
2. the products
3. the processes
4. the chemicals
The substances that are formed by the end of a chemical reaction are called
1. the products
2. the reactants
3. the processes
4. the chemicals
Photosynthesis is an important chemical reaction that takes place in plants.
This process may be represented by a chemical equation. Fill in the blanks in this equation:
Carbon dioxide + Water → _____________ + ___________
1. Glucose + Oxygen
2. Glucose + Air
3. Starch + Oxygen
4. Starch + Glucose
Respiration is an important chemical reaction that takes place in plants and animals. This process may be represented by a chemical equation. Fill in the blanks in this equation:
Glucose + Oxygen → _______ + _________
1. Carbon dioxide + Water
2. Carbon dioxide + Air
3. Water + Nitrogen
4. Air + Water
Which French scientist showed that matter was neither created or destroyed during a chemical reaction?
1. Antoine Lavoisier
2. Marie Curie
3. Louis Pasteur
4. Pierre Curie
Fill in the blanks:
_______ cannot be created or destroyed, but can be __________ from one form to another.
1. Matter, changed
2. Liquids, changed
3. Matter, produced
4. Gases, sent
Complete the following sentence:
In any chemical reaction, the total mass of the reactants is always equal to the mass of the ___________.
1. products
2. processes
3. particles
4. molecules
12 grams of baking soda and 7 grams of vinegar are mixed together in a sealed container whose mass is 25 grams. After the reaction has completed, what will the combined mass of the container and products be?
1. 44 grams
2. 19 grams
3. 37 grams
4. less tham 19 grams
There are two forms of copper sulfate. One of these looks like a powder, while the other is crystalline in appearance.
What are the colours of these substances?
1. White powder, blue crystal
2. Blue powder, colourless crystal
3. White powder, yellow crystal
4. Yellow powder, blue crystal
The minimum amount of energy needed before reactants can form a product is called
1. activation energy
2. exothermic energy
3. reaction energy
4. nuclear energy
Water can be broken down into hydrogen and oxygen gases.
In such a reaction, 24 cm³ of hydrogen gas is formed. What volume of oxygen gas should be formed in the same reaction?
1. 12 cm³
2. 24 cm³
3. 48 cm³
4. 18 cm³
The reaction where water is chemically broken down by passing an electric current through it, is called
1. electrolysis
2. endothermic
3. exothermic
4. electronic
In an exothermic reaction, the energy of the reactants is _________ the energy of the products.
1. greater than
2. less than
3. equal to
In an endothermic reaction, the energy of the reactants is _________ the energy of the products.
1. less than
2. greater than
3. equal to
The speed at which a reaction occurs is called its
1. reaction rate
2. velocity
3. activation energy
4. exothermic rate
The minimum energy required in order that a reaction may take place is known as
1. the activation energy
2. the reaction energy
3. the endothermic energy
4. the exothermic energy
The rate of reaction can easily be measured.
Which one of the following does not measure the rate of a reaction?
1. Recording the colour of the reacting mixture as the reaction takes place.
2. Measuring the amount of one of the products present as the reaction takes place.
3. Measuring the amount of one of the reactants present as the reaction takes place.
4. Measuring the temperature of the reaction.
Which of the following factors does NOT affect the rate of a chemical reaction?
1. Colour of the reactants
2. Number of particles reacting
3. Temperature of the reactants
4. Size of the reactants
Which one of the following chemical reactions takes place at the greatest rate?
1. A match burning
2. An egg boiling
3. Paint drying
4. Cement setting
If the temperature of a reaction is decreased, what effect will this have on the reaction rate?
1. The rate of reaction will decrease.
2. The rate of reaction will increase.
3. It will have no effect.
4. The reaction will stop.
When sodium thiosulfate is added to hydrochloric acid, a slow reaction takes place in which a coloured precipitate of sulfur forms.
What colour is this precipitate?
1. Yellow
2. Red
3. White
4. Green
Which one of the following factors increases the reaction rate?
1. More collisions between the reacting particles
2. Lowering the temperature of the reacting particles
3. Diluting the reactants
4. Placing the reactants in the dark
Which one of the following does heating the reactants generally NOT do to a reaction?
1. Slows down the speed of the particles
2. Increase the energy of the colliding particles
3. Cause more collisions
Which of the following does NOT usually happen during a chemical reaction?
1. There is no heat change
2. It is usually impossible to reverse the reaction
3. New substances are formed
4. There is usually an energy change
Peeling an apple is an example of a physical change.
1. TRUE
2. FALSE
Adding sugar to a cup of tea is a physical change because
1. it is possible to separate the sugar from the tea
2. there is no change in colour
3. there is no change in temperature
4. the tea tastes sweeter
Exothermic and endothermic reactions always involve a change in
1. heat
2. colour
3. volume
4. density
When you sweat, your body must supply heat so that the sweat evaporates.
This is an example of
1. an endothermic reaction
2. an exothermic reaction
Which one of the following is an exothermic reaction?
1. Coal burning
2. An egg boiling
3. Water evaporating
4. Chocolate melting
Magnesium burns in air with a bright flame, and a white powder forms.
We know that this is a chemical reaction because
1. a new substance is formed
2. you should not stare at the light
3. it can easily be reversed
4. magnesium is a metal
When performing an experiment to study the conditions necessary for rusting, some water is boiled and allowed to cool. Why is this done?
1. To remove oxygen that may be dissolved in the water
2. To purify the water
3. To sterilise the water
4. To wash the metal being tested
In an endothermic reaction, the products have _______ energy compared to the reactants.
1. more
2. less
3. the same

Chemical Reactions

Multiple Choice Quiz