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Balancing Chemical Equations
Multiple Choice
Fill in the Blank
Multiple Choice 2
Balancing Equations 2
100

Balance this Equation:

Na + Cl2 -> NaCl

2Na + Cl2 -> 2NaCl

100

Which of the following is NOT an example of a chemical reaction?

a. milk turning sour

b. food being digested

c. a match burning

d. ice melting

d. ice melting

100

A shorthand notation that represents a compound or diatomic molecule is called a(n) _____________.

chemical formula

100

In which kind of chemical reaction do two or more substances combine to form one new compound?

a. synthesis

b. decomposition

c. single-displacement

d. double-displacement

a. synthesis

100

Ag2O -> Ag + O2

2Ag2O -> 4Ag + O2

200

CO2 + H2O + energy -> C6H12O6 + O2

6CO2 + 6H2O + energy -> C6H12O6 + 6O2

200

Which of the following is an example of a diatomic molecule?

a. NaCl

b. O2

c. Mg

d. CaCl2

b. O2

200

The minimum amount of energy needed to start a reaction is called _____________.

activation energy

200

Which of the following usually increases the rate of a reaction?

a. decreasing the concentration of the reactants

b. grinding a solid reactant into a powder

c. lower the temperature of the reactants

d. raising the temperature of the products

b. grinding a solid reactant into powder

200

NaBr + CaF2 -> NaF + CaBr2

2NaBr + CaF2 -> 2NaF + CaBr2

300

H2CO3 -> H2O + CO2

H2CO3 -> H2O + CO2

300

For a chemical bond to break,

a. individual atoms must be present

b. energy is required

c. covalent compounds must be mixed

d. solids must be dissolved

b. energy is required

300

In a(n) ________________ reaction, ions in different compounds switch places.

double-displacement

300

Which of the following is an example of a chemical reaction?

a. a tire losing air

b. water boiling

c. a solid forming in solution

d. ice melting

c. a solid forming in solution

300

S8 + O2 -> SO3

S8 + 12O2 -> 8SO3

400

Zn + HCl -> ZnCl2 + H2

Zn + 2HCl -> ZnCl2 + H2

400

Which of the following phrases describes a catalyst?

a. slows the rate of a reaction

b. increases the energy given off by a reaction

c. lowers the activation energy of a reaction

d. changes permanently when used in a reaction

c. lowers the activation energy of a reaction

400

In a chemical formula, if no _________ is written after an element, then only one atom of the element is present.

subscript

400

How can the rate of reaction be increased?

a. by decreasing the concentration of the reactants

b. by grinding a solid reactant into a powder

c. by lowering the temperature of the reactants

d. by raising the temperature of the products

b. by grinding a solid reactant into a powder

400

CH4 + O2 -> CO2 + H2O

CH4 + 2O2 -> CO2 + 2H2O

500

Pb(OH)2 + HCl -> H2O + PbCl2

Pb(OH)2 + 2HCl -> 2H2O + PbCl2

500

Why does the law of conservation of mass dictate that chemical equations be balanced?

a. because atoms are never gained or lost in a chemical reaction

b. because elements are classified by weight

c. because chemical formulas are written from left to right

d. because using the wrong chemical symbol causes confusion

a. because atoms are never gained or lost in a chemical reaction

500

A substance that slows down or stops a chemical reaction is called a(n) ______________.

inhibitor

500

Which of the following equations is an example of a single-displacement reaction?

a. Fe + 2HCl -> FeCl2 + H2

b. 2Mg + O2 -> 2MgO

c. 2H2O2 -> 2H2O + O2

d. NaOH + HCl -> NaCl + H2O

a. Fe + 2HCl -> FeCl2 + H2

500

C3H8 + O2 -> CO2 + H2O

2C3H8 + 25O2 -> 16CO2 + 18H2O