WorksheetsChemical Reactions
Total questions: 34
Worksheet time: 17mins
Which of the following is true about chemical reactions?
They are accompanied by changes in energy.
They form new substances with new properties.
both A and B
neither A nor B
In an endothermic reaction, energy is
absorbed.
released.
converted to mass.
synthesized.
Which of the following is NOT a physical property?
melting point
state of matter
density
flammability
Substances formed as a result of a chemical reaction are called
catalysts.
precipitates.
products.
reactants.
In an exothermic reaction, products have more energy than reactants.
true
false
Water boils at 100°C. This is an example of a chemical property.
true
false
Substances that enter into a chemical reaction are called products.
true
false
The ability to react with oxygen is an example of a chemical property.
true
false
Another name for a chemical change is a chemical bond.
true
false
In a physical change, some of the physical properties of the substance may be altered and the chemical composition remains the same.
true
false
In a balanced chemical equation,
atoms are conserved.
coefficients are equal.
molecules are equal.
energy is not conserved.
When the equation Al + Br2 → AlBr3 is balanced, the coefficient for Al is
1
2
3
4
The reaction in which hydrogen and oxygen are produced by running an electric current through water is an example of
single replacement.
decomposition.
synthesis.
double replacement.
A reaction that has two compounds as reactants and two compounds as products is most likely a
synthesis reaction.
single replacement reaction.
double replacement reaction.
decomposition reaction.
A number written in front of a chemical formula is a(n)
coefficient.
subscript.
valence electron.
The principle that states that matter is neither created nor destroyed during a chemical reaction is called the law of
chemical energy.
conservation of mass.
thermodynamics.
The production of carbon dioxide during the burning of a fuel is an example of a(n) _____ reaction.
physical
endothermic
synthesis
In a chemical equation, the arrow is read as
equals.
leads to.
yields.
In the balanced chemical equation for the formation of ammonia (NH3) from nitrogen (N2) and hydrogen (H2), the sum of the coefficients is
4
6
8
The law of conservation of mass was first demonstrated by the French chemist
Antione Lavioser
Marie Curie
N. Bohr
Increasing the surface area of the reactants will decrease the rate of the reaction.
true
false
The amount of a substance in a given volume is the concentration of the substance.
true
false
The effect of a catalyst on a reaction is to raise the activation energy.
true
false
Only some reactions require activation energy.
true
false
An inhibitor decreases the rate of a reaction.
true
false
The burning of fuels, such as coal, natural gas, or oil, involves a(n) _____ reaction.
physical
endothermic
exothermic
In an endothermic reaction, the energy of the products is
_____ the energy of the reactants.
greater than
less than
equal to
Increasing the temperature of a reaction will _____ the rate of the reaction.
increase
decrease
not affect
The amount of a substance in a given volume is called _____.
atomic weight
molecular weight
concentration
Biological catalysts in the human body are called _____.
enzymes
inhibitors
conductors
What type of reaction is shown? FeS + HCl → FeCl2 + H2S
synthesis
replacement
decomposition
What type of reaction is shown? Na + F2 → NaF
synthesis
replacement
decomposition
What type of reaction is shown? HgO → Hg + O2
synthesis
decomposition
replacement
What is the substance present before a reaction?
reactant
product
