Science chem 4 quiz

2H2 + O2 --> 2H2O How many oxygen molecules are needed to produce two H2O molecules?

1

2H2 + O2 --> 2H2O How many hydrogen molecules are needed to produce two H2O molecules?

2

2H2 + O2 --> 2H2O How many oxygen atoms are needed to produce two H2O molecules?

2

___Cu + O2 -> ___CuO

2,2

___NaOH + H2SO4 -> Na2SO4 + ___H2O

2,2

___Al + ___Cl2 -> ___AlCl3

2,3,2

Ag + H2S -> Ag2S + H2 Balance

2Ag + H2S -> Ag2S + H2

Aluminum metal reacts with copper (II) chloride to produce aluminium chloride and copper metal.

2Al + 3CuCl2 -> 2AlCl3 + 3Cu

Co + H2O -> Co2O3 + H2 Balance

2Co + 3H2O -> Co2O3 + 3H2

HgO -> Hg + O2 Balance

2HgO -> 2Hg + O2

Sodium metal reacts with water to produce sodium hydroxide and hydrogen gas

2Na + 2H2O -> 2NaOH + H2

At temperatures reached during baking, sodium bicarbonate decomposes to produce sodium carbonate, carbon dioxide, and dihydrogen monoxide

2NaHCO3 → Na2CO3 + CO2 + H2O

Zinc metal reacts with oxygen gas to produce zinc oxide

2Zn + O2 -> 2ZnO

N2 + ___H2 -> ___NH3

3,2

Zinc metal reacts with phosphoric acid to produce zinc phosphate and hydrogen gas

3Zn + 2H3PO4 -> Zn3(PO4)2 + 3H2

2H2 + O2 --> 2H2O How many hydrogen atoms are needed to produce two H2O molecules?

4

___Na + O2 -> ___Na2O

4,2

Fe + O2 -> Fe2O3 Balance

4Fe + 3O2 -> 2Fe2O3

___Fe + ___H2O -> ___Fe3O4 + ___H2

6,8,2,8

Aluminium sulfate reacts with barium iodide to produce aluminium iodide and barium sulfate

Al2(SO4)3 + 3BaI2 -> 2AlI3 + 3BaSO4

2H2 + O2 --> 2H2O Why is there no coefficient for O2?

Because it is already balanced

CH4 + O2 → CO2 + H2O Balance

CH4 + 2O2 → CO2 + 2H2O

(...) What does burning produce?

Carbon dioxide, water, heat energy

(...) what does respiration produce?

Carbon dioxide, water, heat energy

Chemical or physical? The burning of magnesium

Chemical

2H2 + O2 --> 2H2O What do we call the number 2 in front of the H2?

Coefficient

What are the words of the week?

Consonant and perfidious

Exothermic or endothermic? The evaporation of a volatile liquid

Endothermic

Exothermic or endothermic? The addition of concentrated sulfuric acid to water

Exothermic

Exothermic or endothermic? The burning of magnesium

Exothermic

Exothermic or endothermic? The condensation of steam to water

Exothermic

H2 + Cl2 -> HCl Balance

H2 + Cl2 -> 2HCl

2H2 + O2 --> 2H2O What are the reactants?

H2 and O2 (hydrogen and oxygen)

2H2 + O2 --> 2H2O What is the product?

H2O (water)

Use consonant in a sentence

He decided to take mathematics rather than physics, as it was more consonant with what he pictures himself doing in the future.

Use perfidious in a sentence

His perfidious nature often meant that his relationships ended abruptly.

2H2 + O2 --> 2H2O Write a word equation that you would use to describe this reaction.

Hydrogen and oxygen react to produce water (dihydrogen monoxide)

Define consonant

In agreement or harmony with

Iron rusts because it reacts with oxygen in the air to form a compound called iron (III) oxide

Iron + oxygen -> iron (III) oxide

(...) what causes rusting?

Iron, oxygen, water (moisture)

If a substance ___ oxygen during a reaction, it is reduced

Loses

What is the most important thing that shows us that a chemical reaction has taken place?

New substances are made during the reaction

If a substance gains oxygen during a reaction, it is ___

Oxidized

CuO + H2 -> Cu + H2O H2 is ___, CuO is ___

Oxidized, reduced

Zn(s) + Cu2+(an) -> Zn2+(aq) + Cu(s) What type of agent are copper (II) ions acting as in this reaction?

Oxidizing agent

Lead (II) nitrate reacts with sodium bromide to produce lead (II) bromide and sodium nitrate

Pb(NO3)2 + 2NaBr -> PbBr2 + 2NaNO3

Lead (IV) sulfide reacts with oxygen gas to produce lead (IV) oxide and sulfur dioxide

PbS2 + 3O2 -> PbO2 + 2SO2

Chemical or physical? The dissolving of sugar in water

Physical

Chemical or physical? The melting of ice

Physical

Chemical or physical? The sublimation of solid carbon dioxide

Physical

LAB: what were the reactants of this lab? What were the products?

Reactants: borax/sodium tetraborate dehydrate (Na2B4O7), water (H2O), and glue (C4H6) Product: slime

Zn(s) + Cu2+(an) -> Zn2+(aq) + Cu(s) Cu is ___, Zn is ___

Reduced, oxidized

CuO + H2 -> Cu + H2O What type of agent is hydrogen acting as in this reaction?

Reducing agent

Sodium reacts strongly with water to give a solution of sodium hydroxide; hydrogen gas is given off

Sodium + water -> sodium hydroxide + hydrogen

Sodium hydroxide neutralises sulfuric acid to form sodium sulfate and water

Sodium hydroxide + sulfuric acid -> sodium sulfate + water

2H2 + O2 --> 2H2O Is the reaction balanced?

Yes

LAB: what evidence did you see that a chemical reaction took place? Explain.

a new substance (slime) was formed and it is difficult to reverse.

LAB: do you think this was a synthesis or decomposition reaction?

a synthesis reaction, as multiple substances (borax, water, glue) combine to form a new substance (slime). This is a synthesis reaction and not a decomposition reaction because one substance does not chemically break down into multiple new substances.

Define perfidious

deceitful and untrustworthy

Reduction is the ____ of electrons

gain

Oxidation is the ____ of electrons

loss