CONSERVATION OF MASS TAKS QUESTIONS
July 2004-11:
(25) When the above equation is balanced, the coefficient for magnesium chloride is —
A0
B* 1
C2
D4
July 2004-11:
(40) If all the reactants in a chemical reaction are completely used, which of the
following statements accurately describes the relationship between the reactants and the
products?
F The products must have a different physical state than the reactants.
G* The total mass of the reactants must equal the total mass of the products.
H The reactants must contain more complex molecules than the products do.
J The density of the reactants must equal the density of the products.
Use the information below and your knowledge of science to answer questions 9–11.
The first equation represents photosynthesis. Plants use energy from sunlight to produce
sugar and oxygen from carbon dioxide and water. The second equation represents aerobic
respiration. Plants and animals release stored energy in a reaction between sugar
molecules and oxygen. This reaction produces carbon dioxide and water.
Spring 2003-11:
(10) To produce 4 molecules of sugar, a plant needs —
F 6 molecules of hydrogen
G 12 molecules of ATP
H 18 molecules of water
J* 24 molecules of carbon dioxide
Spring 2003-11:
(45) What are the coefficients that will balance this chemical equation?
A 2, 1, 1
B 3, 4, 2
C* 2, 2, 1
D 4, 3, 2
Spring 2003-11:
(19) What is the coefficient for H2O when the above equation is balanced?
A1
B* 2
C3
D4
Spring 2003-11:
(39) According to the law of conservation of mass, how much zinc was present in the
zinc carbonate?
A 40 g
B 88 g
C* 104 g
D 256 g
April 2004-10:
(30) The illustrations show a conservation-of-mass experiment. The solution in the
beaker lost mass because —
F materials have less mass at high temperatures
G the mass of the reactants and products was less than 100 g
H sodium sulfate (Na2SO4) is lighter than air
J* some of the water molecules turned into gas
Spring 2004 – 11:
(29) The chemical equation shows CaCO3 being heated. Which of these statements best
describes the mass of the products if 100 g of CaCO3 is heated?
A The difference in the products’ masses is equal to the mass of the CaCO3.
B The sum of the products’ masses is less than the mass of the CaCO3.
C The mass of each product is equal to the mass of the CaCO3.
D* The sum of the products’ masses equals the mass of the CaCO3.
Spring 2004 – 11:
(32) Which chemical equation supports the law of conservation of mass?
F 2H2O(l) H2 (g) O2 (g)
G Zn(s) HCl(aq) ZnCl2 (aq) H2 (g)
H Al4C3(s) H2O(l) CH4(g) Al(OH) 3(s)
J* CH4 (g) 2O2 (g) CO2 (g) 2H2O(g)
Spring 2004 - 11
(40) When 127 g of copper reacts with 32 g of oxygen gas to form copper (II) oxide, no
copper or oxygen is left over. How much copper (II) oxide is produced?
F 32 g
G 95 g
H 127 g
J* 159 g
October 2005 – 11:
33 The mass of a rusty bicycle is found to be slightly greater than the mass of the same
bicycle before it rusted. The change in mass indicates that the rusting process —
A is a physical change
B involves an energy-to-matter conversion
C decreases the density of the metal
D* involves metal bonding with other atoms
October 2005 – 11, Fall 2005 – 11:
46 Aluminum metal and oxygen gas combine to produce aluminum oxide (Al2O3). Which
of these is the balanced equation for this reaction?
F Al + O2Al2O3
G 2Al + 2O2 2Al2O3
H 2Al + 3O2 5Al2O3
J* 4Al + 3O2 2Al2O3
July 2006 – 11:
12 Which set of coefficients balances the equation?
F 3, 3, 1, 2
G 6, 1, 1, 3
H* 3, 2, 1, 6
J 6, 2, 1, 6
July 2006 – 11:
27 Which of these would support the idea that mass is conserved in a reaction that
produces a gas as a product?
A Heating the reactants to ensure the reaction occurs in a gaseous state
B Subtracting the mass of the gas from the mass of the solid and liquid products
C Mixing the reactants and measuring their total mass
D* Trapping the gas and measuring its mass
February 2006 – 11:
20 Copper (Cu) and sulfur (S) were heated in a covered container. After the reaction was
complete, the unreacted sulfur was removed. The table contains the results of the
investigation. How much sulfur, in grams, failed to react with the copper? Record and
bubble in your answer to the nearest hundredth on the answer document. Answer: 1.32
Fall 2005 – 11:
20 When 50 mL of isopropyl alcohol (39.5 g) is added to 50 mL of water (50 g), the
mixture will have a volume of 98 mL. What is the mass in grams of this mixture? Record
and bubble in your answer to the nearest tenth on the answer document. Answer: 89.5
Fall 2005 – 11:
30 Liquid 1 and Liquid 2 react to produce a solid and a gas. Which of the
following expressions correctly shows how to determine the mass of the
gas?
A.
B.
C.
D.
*(mass of Liquid 1 + mass of Liquid 2)  (mass of solid)
(mass of Liquid 1 + mass of Liquid 2) + (mass of solid)
(mass of Liquid 1 x mass of Liquid 2) ÷ (mass of solid)
(mass of Liquid 1  mass of Liquid 2) ÷ (mass of solid)
April 2006 – 11:
2C2H2(g) + 5O2(g) 4CO2(g) + ___
16 Which additional product balances this reaction?
F 4OH(aq)
G CH4(g)
H H2O2(g)
J* 2H2O(g)
April 2006 – 10:
9 What coefficient values will balance the reaction shown above?
A 2, 2, 1
B 1, 1, 1
C* 2, 1, 2
D 1, 2, 2
April 2006 – 10:
40 In the procedure shown above, a calcium chloride solution is mixed with a sodium
sulfate solution to create the products shown. Which of the following is illustrated by this
activity?
F* The law of conservation of mass
G The theory of thermal equilibrium
H The law of conservation of momentum
J The theory of covalent bonding