Chemistry Test Reactions

In a chemical equation, the formula of a substance in water solution is followed by the symbol

(aq)

In an equation, the symbol for a substance in water solution is followed by

(aq)

The formation of a solid product in a chemical reaction is represented by the symbol

(s)

Which coefficients correctly balance the formula equation CaO + H2O → Ca(OH)2?

1, 1, 1

Which coefficients correctly balance the formula equation NH4NO2(s)→ N2(g) + H2O(l)?

1, 1, 2

Which set of coefficients will balance the equation below? NaOH + Cu(NO3)2 Cu(OH)2 + NaNO3

2, 1, 1, 2

Which coefficients correctly balance the formula equation below? KClO3(s) KCl(s) + O2(g)

2, 2, 3

AgNO3 + CuCl2 -> AgCl + Cu(NO3)2

2AgNO3 + CuCl2 -> 2AgCl + Cu(NO3)2

What is the balanced equation when aluminum reacts with copper(II) sulfate?

2Al + 3CuSO4 → Al2(SO4)3 + 3Cu

Which equation is not balanced?

2H2 + O2 --> H2O

Which equation is not balanced?

2H2 + O2 → H2O

Which of the following equations represents a decomposition reaction?

2HgO(s) 2Hg(l) + O2(g)

PbO2 -> PbO + O2

2PbO2 -> 2PbO + O2

When the formula equation CuSO4(aq) + Fe(s) → Fe2(SO4)3(aq) + Cu(s) is correctly balanced, the coefficient of CuSO4(aq) is

3

What is the total number of molecules represented by the following equation? 2C4H10(g) + 13O2(g) 8CO2(g) + 10H2O(g)

33

What is the total number of molecules that is represented by the following chemical equation? NH4NO2 -> N2 + 2H2O

4

Which of the following equations represents the balanced equation for the reaction of iron and oxygen?

4Fe + 3O2 -> 2Fe2O3

When the equation Fe3O4 + Al → Al2O3 + Fe is correctly balanced, what is the coefficient of Fe?

9

Which of the following may indicate that a chemical reaction has occurred?

All of the above

Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen?

C + O2 → CO2

The word equation solid carbon + oxygen gas → carbon dioxide gas + energy, represents a chemical reaction because

CO2 has chemical properties that differ from those of C and O

Calcium carbonate -> calcium oxide + carbon dioxide

CaCO3 -> CaO + CO2

Predict what happens when calcium metal is added to a solution of magnesium chloride

Calcium Chloride forms

Cl2(g) + MgBr2(aq) ->

Cl2(g) + MgBr2(aq) -> MgCl2(aq) + Br2(l)

A mixture of propane and oxygen react to form carbon dioxide and water. What type of chemical reaction is this?

Combustion

Write a balanced chemical equation for the following reaction: iron plus copper(I) nitrate yields iron(II) nitrate plus copper

Fe(s) + 2CuNO3(aq) → Fe(NO3)2(aq) + 2Cu(s)

Which of the following equations represents a double-displacement reaction?

FeS(s) + 2HCl(aq) -> H2S(g) + FeCl2(aq)

In the reaction Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g), what element has been displaced?

H

In writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is

H2

In writing a formula equation for a reaction that produces hydrogen gas, the correct representation of hydrogen gas is

H2(g)

Predict what happens when lead is added to nitric acid

Hydrogen is released

Which word equation represents the reaction that produces water from hydrogen and oxygen?

Hydrogen plus oxygen yields water

Which of the following is true regarding the law of conservation of mass?

It dictates that the number of atoms of each element must be the same on both sides of a chemical equation

Which of the following is not true regarding a properly written chemical equation?

It must show the formation of a precipitate or a gas

Which equation below violates the law of conservation of mass?

KCl + Br2 -> KBr + Cl2

Magnesium + Oxygen --> Magnesium oxide

Mg + O2 --> MgO

In the chemical equation 2Mg(s) + O2(g) → 2MgO(s),

Mg represents the reagent magnesium

Mg(s) + Co(NO3)2(aq) ->

Mg(s) + Co(NO3)2(aq) Mg(NO3)2(aq) + Co(s)

Predict the product of the reaction represented by the following equation: MgO + CO2 →

MgCO3

Magnesium bromide (aq) + chlorine (g) yields

MgCl2(aq) and Br2(l)

The formulas for the products of the reaction between sodium hydroxide and sulfuric acid are

Na2SO4 and H2O

In the word equation, sodium oxide + water → sodium hydroxide, the formula for sodium hydroxide is represented by

NaOH

Ni(s) + CuCl2(aq) ->

Ni(s) + CuCl2(aq) -> NiCl2(aq) + Cu(s)

How would oxygen be represented in the formula equation for the reaction of methane and oxygen to yield carbon dioxide and water?

O2

Which of the following is true regarding single-displacement reactions?

One element replaces another in a compound

Write a balanced chemical equation for the synthesis of liquid phosphorus trichloride, PCl3, from white phosphorus, P4, and chlorine gas

P4(s) + 6Cl2(g) → 4PCl3(l)

What is the balanced equation for the combustion of sulfur?

S(s) + O2(g) → SO2(g)

You mix solution A with solution B in a beaker. Which of the following observations does not help you prove that a chemical reaction has occurred?

Solution A, solution B, and the mixture are all yellow

CaO(s) + H2O(l) Ca(OH)2(s)

Synthesis reaction

Which of the following indicates that a chemical equation is balanced?

The numbers of atoms of each element are the same on both sides of the equation

Which of the following is true regarding double-displacement reactions?

Two products are formed, the ions of the two reactants must be exchanged, and a precipitate may form

Zn(OH)2 + CH3COOH -> Zn(CH3COO)2 + H2O

Zn(OH)2 + 2CH3COOH Zn(CH3COO)2 + 2H2O

The complete balanced equation for the reaction between zinc hydroxide and acetic acid is

Zn(OH)2 + 2CH3COOH → Zn(CH3COO)2 + 2H2O

Zn(s) + HCl(aq) ->

Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)

What is the small whole number that appears in front of a formula in a chemical equation?

a coefficient

In the expression 3CO2, the numbers 3 and 2 are, respectively

a coefficient and a subscript

When a solid produced by a chemical reaction separates from the solution it is called

a precipitate

To balance a chemical equation, you must

adjust the coefficients

After the first steps in writing an equation, the equation is balanced by

adjusting coefficients to the smallest whole-number ratio

In the equation 2Al(s) + 3Fe(NO3)2(aq) → 3Fe(s) + 2Al(NO3)3(aq), iron has been replaced by

aluminum

According to the law of conservation of mass, the total mass of the reacting substances is

always equal to the total mass of the products

An insoluble gas that forms in a double-displacement reaction in aqueous solution

bubbles out of solution

The reaction of calcium oxide, CaO, with water yields

calcium hydroxide

When heated, a metal carbonate decomposes into a metal oxide and

carbon dioxide

Which observation does not indicate that a chemical reaction has occurred

change in total mass of substances

From a complete and correctly written chemical equation, you can obtain the

chemical formulas of the reactants and products, relative amounts of the reactants and products, and physical states of the reactants and products

To balance a chemical equation, it is permissible to adjust the

coefficients

To balance a chemical equation, it may be necessary to adjust the

coefficients

The reaction 2C2H2(g) + 5O2(g) 4CO2(g) + 2H2O(l) is

combustion reaction

Tell what type of chemical reaction is represented by the following formula equation. Then balance the equation. C3H8(g) + O2(g) -> CO2(g) + H2O(l)

combustion, C3H8(g) + 5O2(g) -> 3CO2(g) + 4H2O(l)

Calcium carbonate, CaCO3, reacts to form calcium oxide, CaO, and carbon dioxide, CO2. What type of reaction is this?

decomposition

The reaction represented by the equation 2HgO(s) → 2Hg(l) + O2(g) is classified as a(n) ____________________ reaction

decomposition

2H2O(l) --> 2H2(g) + O2(g)

decomposition reaction

In what kind of reaction does a single compound produce two or more simpler substances?

decomposition reaction

The equation AX → A + X is the general equation for a

decomposition reaction

The reaction represented by the equation 2HgO(s) → 2Hg(l) + O2(g) is a(n)

decomposition reaction

The reaction represented by the equation 2KClO3(s) → 2KCl(s) + 3O2(g) is a(n)

decomposition reaction

The reaction represented by the equation Mg(s) + 2HCl(aq) → H2(g) + MgCl2(aq) is classified as a(n) ____________________ reaction

displacement

In what kind of reaction does one element replace a similar element in a compound?

displacement reaction

In a chemical equation, the symbol (aq) indicates that the substance is

dissolved in water

HCl(aq) + NaOH(aq) ---> NaCl(aq) + H2O(l)

double displacement reaction

In a reaction, the ions of two compounds exchange places in aqueous solution to form two new compounds. This reaction is called a

double-displacement reaction

In what kind of reaction do the ions of two compounds exchange places in aqueous solution to form two new compounds?

double-displacement reaction

The equation AX + BY → AY + BX is the general equation for a

double-displacement reaction

The reaction Pb(NO3)2(aq) + 2KI(aq) PbI2(s) + 2KNO3(aq) is a

double-displacement reaction

The reaction represented by the equation Pb(NO3)2(aq) + 2KI(aq) → PbI2(s) + 2KNO3(aq) is a

double-displacement reaction

Tell what type of chemical reaction is represented by the following formula equation. Then balance the equation. KBr(aq) + Mg(OH)2(aq) -> KOH(aq) + MgBr2(aq)

double-displacement, 2KBr(aq) + Mg(OH)2(aq) -> 2KOH(aq) + MgBr2(aq)

The decomposition of a substance by an electric current is called

electrolysis

Which of the following is a product that can be formed by double displacement reactions?

gas, precipitate, water

The replacement of bromine by chlorine in a salt is an example of a single-displacement reaction by

halogens

Active metals react with certain acids, such as hydrochloric acid, to yield a metal compound and

hydrogen

Group 1 metals react with water tterm-48o produce metal hydroxides and

hydrogen

When potassium reacts with water, one product formed is

hydrogen gas

The coefficients in a chemical equation

indicate the number of moles of each substance that react

Which of the following is a product in the reaction described by the word equation below? iron + copper(II) sulfate iron(II) sulfate + copper

iron(II) sulfate, copper

Oxides of active metals, such as CaO, react with water to produce

metal hydroxides

What does CH4 represent in the balanced chemical equation shown below? C + 2H2 -> CH4

one molecule of CH4

In one type of synthesis reaction, an element combines with oxygen to yield a(n)

oxide

A precipitate may form in a double-displacement reaction when

positive ions combine with negative ions

The production of a slightly soluble solid compound in a double-displacement reaction results in the formation of a

precipitate

When a slightly soluble solid compound is produced in a double-displacement reaction, a

precipitate is formed

An active metal and a halogen react to form a(n)

salt

A chemical equation is balanced when the

same number of each kind of atom appears in the reactants and in the products

What type of chemical reaction does the following chemical equation represent? 2HCl(aq) + Cr(s) H2(g)+ CrCl2(aq)

single-displacement

Cl2(g) + 2KBr(aq) 2KCl(aq) + Br2(l)

single-displacement reaction

The equation A + BX → AX + B is the general equation for a

single-displacement reaction

The reaction Mg(s) + 2HCl(aq) H2(g) + MgCl2(aq) is a

single-displacement reaction

The reaction represented by the equation Cl2(g) + 2KBr(aq) → 2KCl(aq) + Br2(l) is a(n)

single-displacement reaction

The reaction represented by the equation Mg(s) + 2HCl(aq) → H2(g) + MgCl2(aq) is a

single-displacement reaction

In the chemical reaction represented by the equation 2Cr(s) + 3O2(g) → 2CrO3(s), two chromium atoms combine with ____________________ oxygen atoms

six

In the reaction described by the word equation sodium + water sodium hydroxide + hydrogen gas

sodium hydroxide is a product, water is a reactant

In the chemical equation 2AlCl3(aq) + 3Pb(NO3)2 (aq) → 3PbCl2(s) + 2Al(NO3)3(aq), the state of PbCl2 is a(n)

solid

In which type of reaction do two or more compounds react to form one product?

synthesis

What type of chemical reaction is represented by the following word equation? iron + oxygen iron(II) oxide

synthesis

What type of chemical reaction results in the formation of a single product?

synthesis

In what kind of reaction do two or more substances combine to form a new compound?

synthesis reaction

The equation A + X → AX is the general equation for a(n)

synthesis reaction

The reaction represented by the equation 2Mg(s) + O2(g) → 2MgO(s) is a

synthesis reaction

Tell what type of chemical reaction is represented by the following formula equation. Then balance the equation. Ga(s) + S(s) -> Ga2S3(s)

synthesis, 2Ga(s) + 3S(s) -> Ga2S3(s)

In a chemical reaction

the mass of the reactants equals the mass of the products

When a binary compound decomposes, what is produced?

two elements

In a double-displacement reaction, hydrogen chloride and sodium hydroxide react to produce sodium chloride. Another product is

water

Magnesium hydroxide decomposes to yield magnesium oxide and

water

Many metal hydroxides decompose when heated to yield metal oxides and

water