Unit 5 Study Guide KEY
1.
Evidence of a chemical reaction a.
http://s3.amazonaws.com/engrademyfiles/4083594911742369/Evidence_for_Chemical_Reactions.pdf
2.
Writing word and skeleton equations when given sentence descriptions of chemical reactions. a.
Aqueous ammonium chloride reacts with aqueous sodium hydroxide to form ammonia gas, liquid water, and aqueous sodium chloride. word eqn: ammonium chloride(aq) + sodium hydroxide (aq)  ammonia (g) + water (l) + sodium chloride (aq) skeleton eqn: NH
4
Cl (aq) + NaOH (aq) 
3
(g) + H
2
O (l) + NaCl (aq) double-replacement b.
Aqueous sodium phosphate and liquid water are formed when aqueous sodium hydroxide reacts with phosphoric acid. word eqn:sodium hydroxide (Aq) + phosphoric acid (aq)
 water (l) skeleton eqn: 3NaOH (aq) + H
3
PO
4
(aq)
 double-replacement
3
PO
4
(aq) + 3H
2
O (l) c.
When heated, solid carbon reacts with oxygen gas to form carbon monoxide gas. word eqn: carbon (s) + oxygen (g)  skeleton eqn: 2C (s) + O
2
(g)

2CO (g) synethesis d.
Solid carbon reacts with oxygen gas to form carbon dioxide gas. word eqn: carbon (s) + oxygen (g)  skeleton eqn: C (s) + O
2
(g)
 synthesis
2
(g)

e.
Solid sodium reacts with liquid bromine to form solid sodium bromide. word eqn: sodium (s) + bromine (l)  skeleton eqn: 2Na(s) + Br
2
(l)

2NaBr (s) synthesis f.
When heated, solid potassium chlorate yields solid potassium chloride and oxygen gas. word eqn: potassium chlorate (s)
 skeleton eqn: 2KClO
3
(s)

2KCl (s) + 3O
2
(g) decomposition g.
Anhydrous (contains no water and is a solid) copper(II) sulfate reacts with liquid water to yield solid copper(II) sulfate pentahydrate ( CuSO
4
• 5 H
2
O ). word eqn: copper (II) sulfate (s) + water (l)
 skeleton eqn: CuSO
4
(s) + 5H
2
O (l)
 not any type
4
• 5 H
2
O h.
When heated, solid calcium hydrogen carbonate yields solid calcium carbonate, carbon dioxide gas, and water vapor. word eqn: calcium hydrogen carbonate (s)  calcium caronate (s) + carbon dioxide (g) + water (g) skeleton eqn: Ca(HCO
3
)
2
(s)  CaCO
3
(s) + CO
2
(g) + H
2
O (g) decomposition i.
Ethane gas, C
2
H
6
(g), reacts with oxygen gas to form carbon dioxide gas and water vapor. word eqn: ethane (g) + oxygen (g)
 carbon dioxide (g) + water (g) skeleton eqn: 2C
2
H
6
(g) + 7O
2
(g)  4CO
2
(g) + 6H
2
O (g) combustion

j.
Aqueous copper(II) nitrate reacts with aqueous sodium iodide to form solid copper(I) iodide, aqueous iodine, and aqueous sodium nitrate. word eqn: copper (II) nitrate (aq) + sodium iodide (aq)  copper (I) iodide (s) + iodine
(aq) + sodium nitrate (aq) double-replacement skeleton eqn: 2Cu(NO
3
)
2
(aq) + 4NaI (aq)

2CuI (s) + I
2
(aq) + 4NaNO
3
(Aq)
3.
Writing skeleton equations (including the physical state!) when given word equations a.
potassium chlorate(s)

potassium chloride(s) + oxygen(g)
2KClO
3
(s)

2KCl (s) + 3O
2
(g) decomposition b.
Lead(IV) oxide(s)

lead(II) oxide(s) + oxygen(g)
2PbO
2
(s)

2PbO(s) + O
2
(g) decomposition c.
aluminum(s) + lead(II) nitrate(aq)

aluminum nitrate(aq) + lead(s)
2Al (s) + 3Pb(NO
3
)
2
(aq)  2Al(NO
3
)
3
(aq) + 3Pb (s) single-replacement d.
potassium(s) + water(l)

potassium hydroxide(aq) + hydrogen(g)
2K(s) + 2H
2
O (l)  2KOH (aq) + H
2
(g) single-replacement e.
sodium sulfite(aq) + hydrochloric acid

sodium chloride(aq) + water(l) + sulfur dioxide(s)
Na
2
SO
3
(aq) + 2HCl (aq)

2NaCl (aq) + H
2
O (l) + SO
2
(s)
Double-replacement f.
ammonium sulfate(aq) + potassium hydroxide(aq)

potassium sulfate(aq) + ammonia(g) + water(l)
(NH
4
)
2
SO
4
(aq) + 2KOH (aq)  K
2
SO
4
(aq) + 2NH
3
(g) + 2H
2
O (l) double-replacement g.
Lead(II) nitrate(aq) + potassium sulfide(aq)

potassium nitrate(aq) + lead(II) sulfide(s)
Pb(NO
3
)
2
(aq) + K
2
S (aq)

2KNO
3
(aq) + PbS (s)
Double-replacement

h.
calcium oxide(s) + diphosphorus pentoxide(s)

calcium phosphate(s)
3CaO (s) + P
2
O
5
(s)

Ca
3
(PO
4
)
2
(s) synthesis i.
Iron(s) + silver acetate(aq)

iron(II) acetate(aq) + silver(s)
Fe (s) + 2AgC
2
H
3
O
2
(aq)

Fe(C
2
H
3
O
2
)
2
(aq) + 2Ag (s)
Single-replacement
4.
Balance the reactions in #2 and #3. SEE ABOVE
5.
Determine the type of reaction for all the reactions in #2 and #3. SEE ABOVE
6.
In the reaction below, use the Law of Conservation of Mass to determine the mass of the missing substance. a.
HNO
3
(aq) + MgSO
4
(aq) --> H
2
SO
4
(aq) + Mg(NO
3
)
2
(aq)
25.0g + 22.0 g = 18.0g + X
47.0 g = 18.0 g + X
47.0g – 18.0g = X
29.0 g = X
If you begin the reaction with 25.0g of nitric acid and 33.0g of magnesium sulfate, and you produced 18.0g of sulfuric acid, how much magnesium nitrate is also produced? b.
Cu (s) + AgNO
3
(aq) --> Ag (s) + Cu(NO
3
)
2
(aq) c.
If you have 5.00g of copper and 16.0g of silver (I) nitrate, and you produced 6.50g of silver, how much copper (II) nitrate is also produced?