WorksheetsChemical Reactions
Total questions: 15
Worksheet time: 10mins
A chemical reaction is a process in which
all reactants change state
products change into reactants
the law of conservation of mass applies
How can a chemical equation be balanced?
changing subscripts
erasing elements as necessary
adding coefficients
adding elements as necessary
What are the products in the equation?
Zn and CuSO4
Zn and Cu
ZnSO4 and Cu
Zn only
The following are the evidences that chemical reaction took place, EXCEPT:
evolution of gas
formation of precipitate
formation of new element
change in the intrinsic properties
What type of reaction is present in the unbalanced equation, NaOH + KNO3 ---> NaNO3 + KOH
combination
decomposition
double replacement
combustion
What type of reaction is present in the unbalanced equation, Fe + NaBr --> FeBr3 + Na
combustion
single replacement
double replacement
acid-base
Which of the following best describes the combustion reaction?
hydrocarbon combines with oxygen to produce CO2 and H2O
hydrogen combines with CO2 to produce O2 and H2O
hydrocarbon combines with H2O to produce CO2 and O2
CO2 combines with oxygen to produce hydroxide and H2O
Chemical equations are balanced by placing the appropriate
___________ before the symbols or formulas of reactants and
products.
subscript
exponent
letter
coefficient
Which of the following is the balanced equation for Zn + HCl --> ZnCl2 + H2?
Zn + HCl --> 2ZnCl2 + H2
Zn + 2HCl --> ZnCl2 + H2
2Zn + HCl --> 2ZnCl2 + H2
Zn + 2HCl --> 2ZnCl2 + H2
Which of the following sets of coefficients can be used to balance the equation, CH4 + O2 --> CO2 + H2O
1,1,2,1,
1,2,1,2
2,1,2,1
2,2,1,1
Which of the following is a balanced reaction?
2C3H8 + 10 O2 → 6CO2 + 8H2O
C3H8 + O2 → CO2 + H2O
C3H8 + O2 → 3CO2 + 2H2O
C3H8 + 5O2 → 3CO2 + 4H2O
Quicklime ( CaO ) is used as a drying agent. When water is added to this, slaked lime Ca(OH)2 is formed. What type of reaction is this?
combination
single displacement
decomposition
double displacement
Which of the following chemical reaction shows the production of water from hydrogen gas and oxygen gas?
2 H2O → 2 H2 + O2
2 H2 + O2 → 2 H2O
3 H2 + O2 → 3 H2O
3 H2O → H2 + 3 O2
Which of the following sets of coefficients can be used to balance the equation, Al + O2 --> Al2O3
2,3,2
2,3,4
4,3,2
2,1,4
The Law of Conservation of Mass states that in a chemical reaction,
mass of the reactants and mass of the products are equal
new elements are formed
new atoms are created
atoms are destroyed
