Unit 3.1 Review

Redox

100

What happens to the electrons of an atom being oxidized and something being reduced?

Oxidation loses electrons. Reduction gains electrons.

200

What is the oxidation number of Cl in HClO₄?

+7

300

Is this reaction REDOX or NONREDOX? Give evidence using oxidation numbers.

Cl₂ (g) + 2Li (s) -> 2LiCl (s)

REDOX

Cl 0 -> -1 reduced

Li 0 -> +1 oxidized

400

Which substance is reduced in this reaction? Give evidence using oxidation numbers.

2FeCl_3(aq) + 2KI_(aq) -> 2FeCl_2(aq) + 2KCl_(aq) + I_2(s)

Fe  +3 -> +2

(reduced is gaining electrons, becoming more negative)

500

Which substance is oxidized in this reaction? Give evidence using oxidation numbers.

2FeCl_3(aq) + 2KI_(aq) -> 2FeCl_2(aq) + 2KCl_(aq) + I_2(s)

I -1 ->0

(oxidized is losing electrons, becoming more positive)

Predicting Products 1

100

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Ethane (C₂H₄) is burned in air.

C₂H_4(g) + 3O_2(g) -> 2CO_2(g) + 2H₂O_(g)

combustion

200

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Sodium oxide is added to hydrogen.

Na₂O_(s) + H_2(g) -> no reaction

single replacement

300

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Aluminum bromide is heated.

2AlBr_3(s) -> 2Al_(s) +3Br_2(l)

decomposition

400

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Potassium oxide is mixed with water.

K₂O_(s) + H₂O_(l) -> 2KOH_(aq)

synthesis

500

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Aqueous gallium bromide is mixed with aqueous lead (II) chlorate

2GaBr_3(aq)+3Pb(ClO₃)_2(aq) -> 3PbBr_2(s)+2Ga(ClO₃)_3(aq)

double replacement

Predicting Products 2

100

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Mercury (II) reacts with iodine.

Hg_(l) + I_2(g) -> HgI_2(s)

synthesis

200

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Pentane (C₅H₁₂) is burned in insufficient oxygen.

2C₅H_12(g) + 11O_2(g) -> 10CO_(g) + 12H₂O_(g)

combustion

300

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Rubidium is added to aqueous copper (II) sulfate

2Rb_(s) + CuSO_4(aq) -> Cu_(s) + Rb₂SO_4(aq)

single replacement

400

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Aqueous magnesium chlorate reacts with carbonic acid

Mg(ClO₃)_2(aq) + H₂CO_3(aq) -> MgCO_3(s) + 2HClO_3(aq)

double replacement

500

Write the balanced reaction with state symbols for the following AND classify the type of reaction:

Aluminum carbonate is heated.

Al₂(CO₃)_3(s) -> Al₂O_3(s) + 3CO_{2 (g)}

decomposition

Balancing

100

Balance the following reaction AND classify the type of reaction:

_Na (s) + _P (s) -> _Na₃P (s)

3, 1, 1

synthesis

200

Balance the following reaction AND classify the type of reaction:

_KOH(aq) + _NiCl₂ (aq) -> _Ni(OH)₂ (s) + _KCl (aq)

2,1,1,2

double replacement

300

Balance the following reaction AND classify the type of reaction:

_Na (s) + _H₂O (l) -> _NaOH (aq) + _H₂ (g)

2, 2, 2, 1

single replacement

400

Balance the following reaction AND classify the type of reaction:

_PBr₃ (l) -> _P₄ (s) + _Br₂ (l)

4,1,6

decomposition

500

Balance the following reaction AND classify the type of reaction:

_C₆H₆ (g) + _O₂ (g)-> _CO₂ (g) + _H₂O (g)

2, 15, 12, 6

combustion

Miscellaneous

100

What are two ways to know a chemical change has occures?

Formation of a solid, formation of a gas, or color change

200

Write an equation that includes all of the information in this statement: Two moles of solid aluminum react with 3 moles of aqueous sulfuric acid to produce 1 mole of aqueous aluminum sulfate and 3 moles of hydrogen gas.

2Al (s) + 3H₂SO₄ (aq) -> Al₂(SO₄)₃ (aq) + 3H₂ (g)

300

Describe what evidence of a chemical change you would see if you were watching the reaction below:

Two moles of solid aluminum react with 3 moles of aqueous sulfuric acid to produce 1 mole of aqueous aluminum sulfate and 3 moles of hydrogen gas.

solid Al disappears, bubbles (formation of a gas)

400

What are the state symbols for the following reaction?

Co + 2HCl -> CoCl₂ + H₂

s, aq, aq, g

500

The following reaction will NOT occur spontaneously. In terms of potential energy of the reactants and products, explain why the reaction will NOT be spontaneous and rather yield No Reaction:

CaSO₄ (s) + 2NaCl (aq) ->Na₂SO₄ (aq) + CaCl₂ (aq)

The products are higher in potential energy than the reactants. Solids are lower in potential energy. The products must be lower in potential energy for the reaction to occurs spontaneously.