Worksheets8th Grade 3.2 Chemical Reactions Test Review
Total questions: 28
Worksheet time: 14mins
Energy is required to break chemical bonds.
True
False
Mass is sometimes lost during a chemical reaction.
True
False
Biological catalysts are called products.
True
False
Products have different properties compared to reactants.
True
False
Increasing the temperature generally decreases the reaction rate.
True
False
To increase the reaction rate, you should increase the concentration of the reaction in the rate-determining (slow) step.
True
False
A new substance that is formed following a chemical reaction is
catalyst
activation energy
product
inhibitor
A reaction that occurs when a substance reacts with oxygen is
endothermic reaction
combustion reaction
exothermic reaction
reactant
A substance that is present before a chemical reaction that then undergoes changes during a chemical reaction is
reactant
catalyst
product
inhibitor
A chemical reaction that releases heat is
endothermic reaction
combustion reaction
reactant
exothermic reaction
A substance that increases the reaction rate without being permanently changed is
catalyst
activation energy
reactant
product
A chemical reaction that absorbs heat is called
endothermic reaction
combustion reaction
exothermic reaction
reactant
A substance used to slow down or stop a chemical reaction is
catalyst
product
inhibitor
reactant
The minimum amount of energy that is required to start a chemical reaction is
product
catalyst
endothermic reaction
activation energy
All chemical reactions involve a change in energy.
True
False
When balancing a chemical equation, it is acceptable to change the subscripts in formula.
True
False
To increase the rate of reaction, what factor must be increased?
temperature
surface area
concentration
all of the above
What forms of energy are either released or absorbed during a chemical reaction?
light and sound
thermal energy
electrical energy
all of the above
What are indicators that a reaction has occurred?
change in color, formation of precipitate, formation of gas, change in mass
change in color, release of energy in form of light or sound, change in mass
formation of gas, odor, color change, formation of precipitate, release of energy in form of light and sound
formation of precipitate, odor, change in mass
Is freezing liquid water to form ice a chemical or physical change? Why?
It is a chemical change because the molecules are transformed into a different substance.
It is a physical change because molecules are not transformed into a different substance.
It is both a physical and chemical change because the molecules are transformed into a different substance.
None of the above
Molecules must collide with enough force and in the proper orientation to react with one another.
True
False
Why does powdered grain ignite at a faster rate than a solid grain block?
Powdered grain has a larger surface area, increasing reaction rate.
Powdered grain has a smaller surface area, increasing reaction rate.
Powdered grain has a higher temperature, increasing reaction rate.
Powdered grain is a catalyst, increasing reaction rate.
What is a synthesis reaction?
a reaction where two or more substances combine to form a product
a reaction where a substance is broken down into two or more products
a reaction that occurs when a substance reacts with oxygen
A + BC → AC + B is an example of what type of reaction?
Synthesis
decomposition
single replacement
double replacement
2AgO(s) →4Ag(s)+O(g) is an example of what kind of reaction?
synthesis
decomposition
single replacement
double replacement
K(s)+MgBr(aq)→KBr(aq)+Mg(s) is an example of what type of reaction?
synthesis
decomposition
single replacement
double replacement
2Mg(s)+O(g)→2MgO(s) is an example of what type of reaction?
synthesis
decomposition
single replacement
double replacement
Pb(OH)(aq)+2HCl(aq)→2HO(l)+PbCl(s) is what type of reaction?
synthesis
decomposition
single replacement
double replacement
