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Topic 5: Chemical formulas and Chemical Equations

22. Balancing equation: Determining coefficients and sums of coefficient

1. Given the unbalance equation :

____Fe2O3 + ______CO ------- > _____Fe + ______CO2

When the equation is correctly balanced using the smallest whole-number coefficients, what is
the coefficient of CO ?
1) 1 2) 2 3) 3 4) 4

2. Given the unbalanced equation: + ____Cu

____Al + ____CuSO4 ---- > ____ Al2(SO4)3

When the equation is balanced using the smallest whole-number coefficients, what is the
coefficient of Al ?
1) 1 2) 2 3) 3 4) 4
3. Given the unbalance equation:
Teacher Preview Copy
___ Mg(ClO3)2(s) -------- > _____ MgCl2(s) + ______O2(g)
What is the coefficient of O2 when the equation is balanced correctly using the smallest
whole-number coefficients?
1) 1 2) 2 3) 3 4) 4
4. When the equation _____Na + _____H2O ---- > ____H2 + ______NaOH

Is correctly balanced using the smallest whole number coefficients, what is the coefficient of H2O ?
4) 4

1) 1

2) 2
3) 3

5. When the equation
___SiO2 + ______ C ---- > _____SiC + ______CO
Is correctly balanced using the smallest whole-number coefficients, the sum of all coefficients is
2) 7

3) 8

1) 6 Teacher Preview Copy 4) 9
6. Given the unbalanced equation:
_____H2O2 ---------> ______H2O + _______O2
What is the sum of all coefficients when the equation is balanced correctly using the smallest
whole- number coefficients?
1) 5 2) 9 3) 3 4) 4
7. Given the unbalanced equation:
__Ca(OH)2 + __ (NH4)2SO4 ----- > ___CaSO4 + ___NH3 + __H2O

What is the sum of all coefficients when the equation is correctly balanced using the smallest
whole-number coefficients?
1) 5 2) 7 3) 9 4) 11
8. When the equation ___C2H4 + ____O2 -------- > ____ CO2 + ___H2O

is correctly balanced using the smallest whole-number, what is the coefficient of O2 ?
2) 2

3) 3

4) 4
1) 1
9. Given the unbalanced equation:
___ C3H8 (g) + ___O2(g) -------- > __CO2(g) + ___H2O (g)
When the equation is balanced correctly using the smallest whole-number coefficients, the sum
of all coefficients is 2) 13 3) 24 4) 26
1) 12

10. Given the unbalanced equation:
___C5H8 + ____O2 ----------> __ CO2 + ___ H2O
When the equation is correctly balanced using the smallest whole-number coefficients, what is
the coefficient of C5H8 ? 2) 5 3) 6 4) 10
1) 1

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