Download Introduction to Chemical Reactions and Equations Study Guide

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Unit VIA: Introduction to Chemical Reactions
Introduction to Chemical Reactions and Equations Study Guide
Learning Targets: 1, 2 & 3
Compound Formulas Review
1. How do you know if a compound is ionic or covalent?
Ionic – bond between a metal and nonmetal.
Covalent – bond between a nonmetal and a nonmetal.
2. The numbers written to the bottom right of element symbols in a compound are called
___subscripts________. These numbers tell you the ratio of __atoms______ in the
compound.
3. Sometimes the names of ionic compounds include roman numerals written in parenthesis
after the cation’s name. What do these numbers tell you? Why aren’t they used for all
ionic compounds?
The charge of the metallic ion. Some ions don’t have multiple charges.
4. What information do you have to know before you can write the formula for an ionic
compound?
symbol and charge
5. When determining the subscripts in an ionic compound’s formula, what net charge do
you want the compound to have?
neutral
6. What is the criss-cross method? Give an example to explain it.
We cross the charges to make a neutral compound.
Ca+2
Cl-1
CaCl2
7. When given the name of a covalent compound, how do you know the subscripts to put in
the formula for each type of atom present in the compound?
the prefixes tell us.
Chemical Reactions and Equations Review
8. What happens during a chemical reaction?
one or two compounds or atoms react to form something new.
9. What is the difference between a word equation and a formula equation?
word equation uses words; formula uses symbols
10. In a chemical reaction, the ___reactants_______ are written on the left side of the arrow,
and the __products________ are written on the right side of the arrow.
11. If you read an equation aloud, what do you say when you read the arrow?
__yields_____________
12. What law are we verifying by balancing equations? What does the law say?
law of conservation of matter; matter cannot be created or destroyed
13. What are coefficients? What do they tell you about an equation?
numbers in a chemical reaction that tell us the number of moles reacting
14. What do the letters in parenthesis after a compound’s formula mean? List them and
identify what they stand for.
g - gas
l – liquid
s - solid
aq - aqueous
You have practice worksheets for all of the types of problems that will be on your test. If
you feel that you need more practice over the material, your textbook has a chapter review
on pages 234-236. Here are the questions divided by type of problem:



write word equations from formula equations. (Use #33-36, but write the names
of the compounds instead of balancing the equation.)
write formula equations from word equations or reaction descriptions. (#9-30,
37-49)
balance chemical formula equations. (#33-36, 39-48; and you could balance the
equations in #9-30)
Balancing Equations
1)
1 Na3PO4 + 3 KOH  3 NaOH + 1 K3PO4
2)
1 MgF2 + 1 Li2CO3  1 MgCO3 + 2 LiF
3)
1 P4 + 3 O2  2 P2O3
4)
2 RbNO3 + 1 BeF2  1 Be(NO3)2 + 2 RbF
5)
2 AgNO3 + 1 Cu  1 Cu(NO3)2 + 2 Ag
6)
1 CF4 + 2 Br2  1 CBr4 + 2 F2
7)
2 HCN + 1 CuSO4  1 H2SO4 + 1 Cu(CN)2
8)
1 GaF3 + 3 Cs  3 CsF + 1 Ga
9)
1 BaS + 1 PtF2  1 BaF2 + 1 PtS
10)
1 N2 + 3 H2  2 NH3
11)
2 NaF + 1 Br2  2 NaBr + 1 F2
12)
1 Pb(OH)2 + 2 HCl  2 H2O + 1 PbCl2
13)
2 AlBr3 + 3 K2SO4  6 KBr + 1 Al2(SO4)3
14)
1 CH4 + 2 O2  1 CO2 + 2 H2O
15)
2 Na3PO4 + 3 CaCl2  6 NaCl + 1 Ca3(PO4)2
16)
2 K + 1 Cl2  2 KCl
17)
2 Al + 6 HCl  3 H2 + 2 AlCl3
18)
1 N2 + 3 F2  2 NF3
19)
1 SO2 + 2 Li2Se  1 SSe2 + 2 Li2O
20)
2 NH3 + 1 H2SO4  1 (NH4)2SO4
Writing and Balancing Formula Equations
Step 1: Write each formula and balance each formula using SUBSCRIPTS.
Step 2: Balance the overall equation using coefficients.
1. sulfur reacts with oxygen to yield sulfur dioxide
S + O2 → SO2
2. zinc reacts with sulfuric acid (H2SO4) to yield zinc sulfate and hydrogen
Zn + H2SO4 → ZnSO4 + H2
3. hydrogen reacts with nitrogen to form nitrogen trihydride
3H2 + N2 → 2NH3
4. hydrogen reacts with chlorine to yield hydrogen chloride
H2 + Cl2 → 2HCl
5. carbon reacts with water to form carbon monoxide and hydrogen
C + H2O → CO + H2
6. calcium hydroxide forms when calcium oxide reacts with water
CaO + H2O → Ca(OH)2
7. phosphorus reacts with oxygen to yield diphosphorus pentoxide
4P + 5O2 → 2P2O5
8. sodium chloride and water are produced when hydrogen chloride and sodium hydroxide react
HCl + NaOH → NaCl + H2O
9. barium chloride reacts with sulfuric acid (H2SO4) to produce barium sulfate and hydrogen
chloride
BaCl2 + H2SO4 → BaSO4 + 2HCl
10. aluminum hydroxide and calcium sulfate are produced when aluminum sulfate and calcium
hydroxide react
Al2(SO4)3 + 3Ca(OH)2 → 2Al(OH)3 + 3CaSO4
11. ethane (C2H6) reacts with oxygen to yield carbon dioxide and water
2C2H6 + 7O2 → 4CO2 + 6H2O
12. aluminum and oxygen are formed when aluminum oxide decomposes
2Al2O3 → 4Al + 3O2