UNIT-Atomically Correct
Independent Practice Guide 3
1) The diagrams below represent a chemical reaction at the atomic size scale. For each diagram write the
balanced chemical equation that bests describes the chemical reaction represented.
a)
b)
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c)
2. Balance the following reaction:
a)
KClO3  KCl + O2 (not balanced)
b) How many moles of oxygen would be produced from 4 moles of potassium chlorate?
3. Chlorine can be made by the decomposition of sodium chloride.
NaCl  Na + Cl2 (not balanced)
a) How many moles of sodium and chlorine can be produced from 0.025 mole of sodium chloride?
4. Calcium metal reacts with water to produce calcium hydroxide and hydrogen gas .
Ca + H2O  Ca(OH)2 +
H2 (not balanced)
a) How many moles of calcium will react completely with 0.90 moles of water?
b) What is the mass of 0.90 moles of water?
c) What is the mass of the calcium that will react with 0.90 moles of water?
d) How many moles of hydrogen gas is produced from 0.45 moles of calcium reacting with
an excess of water?
e) What is the mass of the hydrogen gas produced in question d?
5. An excess of ammonium sulfate, (NH4)2SO4 reacts with 20.0 g of calcium hydroxide, Ca(OH)2, to produce
calcium sulfate (CaSO4), ammonia (NH3), and water.
a) Write a balanced equation for this chemical reaction.
b) How many moles of ammonia(NH3) are produced when 20.0g of calcium hydroxide reacts with
ammonium sulfate?
6. The commercial heating gas methane (CH4) burns in a limited amount of oxygen. Under these conditions,
water and carbon dioxide are the products.
a) Write the balanced equation for the burning of methane in oxygen gas.
b) How many grams of oxygen gas would be required to completely burn 4.0 grams of methane?
7. For the following reaction :
H3PO4 + MgCO3  Mg3(PO4)2 + H2O + CO2
(not balanced)
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How many grams of H3PO4 are needed to react with 4.00 g of MgCO3?
8. If a plant needs to produce 30.0 g of glucose(C6H12O6) by combining CO2 and water using
photosynthesis, how many grams of water are required? (O2 is the other product besides glucose.)
9. When sodium metal(Na) is dropped into water a vigorous reaction occurs. Hydrogen gas is
released and a solution of lye, NaOH, remains in the reaction vessel.
a) Write the balanced equation for the process.
b) If 23.0 g of sodium react with water, how many moles of hydrogen will be produced?
c) What will the mass of this hydrogen be?
10. In the laboratory, chlorine is prepared by heating hydrochloric acid with manganese dioxide. The reaction
is:
HCl + MnO2  H2O + MnCl2 + Cl2 (not balanced)
How many grams of HCl react with 5.00 g of manganese dioxide?
11. Hematite, Fe2O3, is an important ore of iron. (An ore is a natural substance from which the metal can be
profitably obtained.) The free metal is obtained by reacting hematite with carbon monoxide in a blast furnace.
Carbon monoxide is formed in the furnace by partial combustion of coal (carbon). The reaction in which the
metal is produced is:
Fe2O3 + CO Fe + CO2 (not balanced)
How many grams of iron can be produced from 1000 g of Fe203?
12. Sphalerite is a zinc sulfide (ZnS) mineral and an important source of zinc metal. The first step in the
processing of the ore consists of heating the zinc sulfide with oxygen to give zinc oxide (ZnO), and sulfur
dioxide. How many grams of oxygen gas combine with 5.00 x 103 g of zinc sulfide in this reaction?
13. British chemist Joseph Priestley prepared oxygen in 1774 by heating mercury(ll)oxide, HgO. Mercury metal
is the other product. If 6.47 g of oxygen are collected, how many grams of mercury metal are also produced?
14. White phosphorus, P4, is prepared by fusing calcium phosphate with carbon and sand,SiO2, in an electric
furnace:
2 Ca3(PO4)2 + 6 SiO2 + 10 C  P4 + 6 CaSiO3 + 10 CO
How many grams of calcium phosphate are required to give 1000g of phosphorus?
15. Tungsten metal, W, is used to make light bulb filaments. The metal is produced from the yellow tungsten
oxide, WO3, by reaction with hydrogen:
WO3 + 3H2  W + 3H2O
How many grams of tungsten can be obtained from 4810 grams of tungsten oxide?
16. The following reaction is used to make carbon tetrachloride, a solvent and starting material
for the manufacture of fluorocarbon refrigerants and aerosol propellants:
CS2 + 3Cl2  CCl4 + S2Cl2
Calculate the number of grams of carbon disulfide, CS2, needed for a reaction with 43.2 g
of chlorine, Cl2.
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