Chemical Engineering Chapter 7 The reaction of baking soda and vinegar

Introductory Chemistry, 5e (Tro)

Chapter 7 Chemical Reactions

True/False Questions

1) The reaction of baking soda and vinegar to produce carbon dioxide gas is an example of a

precipitation reaction.

2) The reaction of carbonate ion with magnesium ion to form solid magnesium carbonate is an

example of an oxidation reduction reaction.

3) Combustion reactions are a subcategory of oxidation-reduction reactions.

4) Color change is evidence that a chemical reaction has occurred.

5) The formation of a gas is evidence of a chemical reaction while the emission of light is not.

6) The formation of a new solid or gas is evidence of a chemical reaction.

2

7) Bubbles in water that appear during boiling show that a chemical reaction is occurring.

8) When balancing a chemical equation you may alter the coefficients but not the subscripts in

the equation.

9) The following equation IS balanced: CH4 + 2O2 → CO2 + H2O

10) The following reaction IS balanced: BaCl2 + H2SO4 → 2HCl + BaSO4

11) The following equation IS balanced: 2 C4H10O + 13 O2 → 8 CO2 + 10 H2O

12) The following reaction IS balanced: AgNO3 + 2NH4Cl → AgCl + (NH4)2NO3

13) The following equation IS balanced: HNO3 + NaHSO3 → NaNO3 + H2O + SO2

14) All ionic compounds dissolve in water.

15) An aqueous solution is a homogeneous mixture of a substance with water and should be

designated with the (l) abbreviation.

16) A strong electrolyte solution contains ionic compounds that completely dissociate in water.

17) An insoluble compound will completely dissolve in water.

18) When compounds containing polyatomic ions dissolve, the polyatomic ions usually dissolve

as intact units.

19) Li+, Na+, K+ and NH4+ compounds are soluble.

20) Cl–, Br–, and I– are mostly insoluble.

21) Precipitation reactions always occur when two aqueous solutions are mixed.

22) Mixing two aqueous solutions will always result in formation of a precipitate.

23) A precipitation reaction occurs when water is formed as a product.

24) The key to predicting a precipitation reaction is the formation of an insoluble compound

from soluble compounds.

25) A precipitation reaction will occur when sodium chloride is mixed with potassium nitrate.

26) A precipitate will form when you mix solutions of potassium chloride and lead nitrate.

27) We remove the spectator ions from the complete ionic equation to form the net ionic

equation.

28) A net ionic equation shows all ionic species that are present in solution.

29) A spectator ion is one that does not actively participate in a chemical reaction.

30) Mixing HNO3 (aq) and NaHCO3 (aq) will produce carbon dioxide gas as a product.

31) One of the characteristics of an acid-base reaction is that this type of reaction forms water.

32) An acid-base reaction always produces a salt plus carbon dioxide.

33) Carbon dioxide gas is a product when an acid reacts with a carbonate or a bicarbonate.

34) The net ionic equation for the reaction of sodium hydroxide plus hydrochloric acid is

.

6

35) An oxidation-reduction reaction must involve reaction with oxygen.

36) Evidence of a redox reaction is when a substance reacts with elemental oxygen.

37) Evidence of a redox reaction is when one substance transfers protons to another substance.

38) In an oxidation-reduction reaction, if one substance loses electrons, then another substance

must gain electrons.

39) Combustion reactions emit heat and so can be classified as endothermic.

40) Decomposition reactions usually require energy to initiate the reaction.

41) The reaction 2 KClO3 → 2 KCl + 3 O2 would be correctly classified as a decomposition

reaction.

Global Outcome: G2

42) It has been shown that the ozone molecule (O3) can be formed when a single oxygen atom

(O) adds to a molecule of oxygen (O2), so this type of reaction is known as a double

displacement reaction.

Multiple Choice Questions

1) A reaction which forms a gaseous product is an example of a(n)________.

A) oxidation-reduction reaction

B) combustion reaction

C) precipitation reaction

D) gas evolution reaction

E) none of the above

2) A reaction which forms a solid product is an example of a(n):

A) oxidation-reduction reaction.

B) combustion reaction.

C) precipitation reaction.

D) gas evolution reaction.

E) none of the above

3) A reaction in which a substance reacts with oxygen, emitting heat and forming oxygen-

containing compounds is an example of a(n):

A) acid-base reaction.

B) combustion reaction.

C) precipitation reaction.

D) gas evolution reaction.

E) none of the above

4) Which of the following is NOT evidence that a chemical reaction has occurred?

A) color change when chemicals are contacted with each other

B) solid formation when chemicals are contacted with each other

C) gas formation when chemicals are contacted with each other

D) emission of light when chemicals are contact with each other

E) All of the above are evidence of a chemical reaction.

5) Which of the following is NOT typically a sign of a chemical reaction?

A) absorbing heat when chemicals are contacted with each other

B) emission of heat when chemicals are contacted with each other

C) emission of light when chemicals are contacted with each other

D) absorbing light when chemicals are contacted with each other

E) All of the above are signs of a chemical reaction.

6) When water is heated, bubbles form in the water. Is this evidence of a chemical reaction?

Why?

A) No, boiling water is a physical change.

B) Yes, the formation of a gas is evidence of a chemical reaction.

C) No, the formation of gas bubbles is a secondary chemical reaction which is ignored.

D) Yes, the formation of a gas is proof a new compound has been made.

E) none of the above

7) Which of the following statements about balancing reactions is FALSE?

A) If there is no coefficient or subscript, a one is implied.

B) When coefficients are added the type of compounds is changed in the chemical reaction.

C) Subscripts are multiplied by the coefficients to determine the number of atoms in a

compound.

D) Coefficients are added to compounds to ensure both sides of the reaction have equal numbers

of each atom.

E) All of the above statements are true.

8) Before a chemical equation can be written, one must know:

A) the atomic mass of all the elements involved.

B) the molar mass of all the compounds.

C) the symbols and formulas of all reactants and products.

D) the number of moles of all reactants and products.

E) none of the above.

9) When the equation, ___N2 + ___H2 → ___NH3 is balanced, the coefficient of hydrogen is:

A) 1

B) 2

C) 3

D) 4

E) none of the above

10) When the equation, ___O2 + ___C5H12 → ___CO2 + ___H2O is balanced, the coefficient:

of O2 is:

A) 3

B) 4

C) 5

D) 8

E) none of the above

11) What are the coefficients for the following reaction when it is properly balanced?

___HCl + ___Mg → ___MgCl2 + ___H2

A) 2, 1, 1, 1

B) 2, 1, 2, 2

C) 1, 2, 1/2, 1

D) 1, 1, 1, 2

E) none of the above

12) What are the coefficients for the following reaction when it is properly balanced?

___O2 + ___CH4 → ___CO2 + ___H2O

A) 2, 1, 3, 1

B) 2, 3, 2, 2

C) 1, 3, 2, 1

D) 2, 1, 1, 2

E) none of the above

13) What are the coefficients for the following reaction when it is properly balanced?

___Na3PO4 + ___Ba(NO3)2 → ___NaNO3 + ___Ba3(PO4)2

A) 2, 1, 1, 3

B) 2, 3, 1, 6

C) 2, 3, 6, 1

D) 6, 1, 3, 2

E) none of the above

14) What are the coefficients for the following reaction when it is properly balanced?

___nitric acid + ___sodium hydroxide → ___sodium nitrate + ___water

A) 2, 1, 1, 1

B) 2, 3, 2, 2

C) 5, 2, 2, 1

D) 1, 1, 1, 1

E) none of the above

11

15) What are the coefficients for the following reaction when it is properly balanced?

___potassium iodide + ___lead (II) acetate → ___lead (II) iodide +___potassium acetate

A) 2, 1, 1, 1

B) 2, 1, 1, 2

C) 3, 2, 2, 1

D) 1, 1, 2, 2

E) none of the above

16) What are the coefficients for the following reaction when it is properly balanced?

___nitrogen monoxide + ___carbon monoxide → ___nitrogen +___carbon dioxide

A) 2, 1, 1, 2

B) 2, 2, 1, 2

C) 2, 2, 2, 1

D) 1, 1, 2, 2

E) none of the above

17) When the equation __Ca3N2 + __H2O → __Ca(OH)2 + __NH3 is balanced, the coefficient

of H2O is:

A) 2

B) 3

C) 6

D) 12

E) none of the above

18) When the equation __NO2 + __H2O + __O2 → __HNO3 is balanced, the coefficient of

HNO3 is:

A) 2

B) 3

C) 4

D) 5

E) none of the above

19) Which of the following equations is NOT balanced properly?

A) 2Cr + 6HCl → 2CrCl3 + 3H2

B) 2NaHCO3 → Na2CO3 + CO2 + H2O

C) Cr2(SO4)3 + 6KOH → 2Cr(OH)3 + 3 K2SO4

D) 4NH3 + 14O2 → 4NO2 + 6H2O

E) none of the above

20) Sodium metal reacts with water to form aqueous sodium hydroxide and hydrogen gas. Which

equation below best describes the balanced equation for this reaction?

A) Na + H2O → NaOH (aq) + H (g)

B) S + H2O → SOH (aq) + H (g)

C) Na + H2O → NaOH (aq) + H2 (g)

D) 2Na + 2H2O → 2NaOH (aq) + H2 (g)

E) 2Na + H2O → Na2OH (aq) + H (g)

21) An aqueous solution is:

A) any liquid with another compound dissolved in it.

B) an ionic compound with water dissolved in it.

C) water with a molecular compound dissolved in it.

D) water with another compound dissolved in it.

E) none of the above

22) Which of the following compounds is INSOLUBLE?

A) potassium acetate

B) lithium carbonate

C) magnesium bromide

D) aluminum sulfide

E) none of the above

23) Which of the following compounds is INSOLUBLE?

A) magnesium phosphate

B) magnesium sulfate

C) magnesium iodide

D) magnesium nitrate

E) none of the above

24) Which of the following compounds is SOLUBLE?

A) copper carbonate

B) calcium carbonate

C) potassium carbonate

D) strontium carbonate

E) none of the above

25) Which of the following compounds is SOLUBLE?

A) aluminum hydroxide

B) aluminum sulfide

C) aluminum carbonate

D) aluminum sulfate

E) none of the above

26) All of the following compounds are soluble in water EXCEPT:

A) NaCl.

B) CaCl2.

C) FeCl3.

D) NH4Cl.

E) PbCl2.

27) The compound sodium sulfate is soluble in water. When this compound dissolves in water,

which ion listed below would be present in solution?

A) SO42-

B) S2-

C) O2-

D) Na22+

E) none of the above

28) When solid NaCl is stirred into water, which of the following is NOT true?

A) Individual sodium and chloride ions are present.

B) The solution will conduct electricity.

C) The solution will taste salty.

D) The NaCl will fail to dissociate.

E) none of the above

29) Several grams of sodium chloride are stirred into a glass of water and are no longer visible to

the eye. Which of the following statements is FALSE?

A) The sodium chloride solid has dissociated into its component ions.

B) An aqueous solution has been prepared.

C) No precipitate has formed.

D) Sodium chloride is insoluble in water.

E) All of the statements are true.