Chemistry 8P14 - Chemical Formulas & Equations

Question 1

This is a chemical reaction for the decomposition of carbonic acid into water and carbon dioxide: H₂CO₃ → H₂O + CO₂

How does the reaction support the Law of Conservation of Mass?

Answer 1

The mass of the atoms in the reactant equals the mass of the atoms in the products.

Question 2

Two different liquids are poured together in an open container. Bubbles begin to form. After the bubbling stops, it is determined that the total weight of the two liquids is less than before they were poured together. Why was the mass less after the reaction, than before?

Answer 2

A) Some of the atoms during the reaction escaped into the air.

Question 3

Which quantities a, b, c, and d are required to balance this equation:

aCuO_(s) + bH_2(g) ==> cCu_(l) + dH₂O_(g

A) 2 1 1 1

B) 1 2 2 1

C) 2 1 2 1

D) 1 1 1 1

Answer 3

D) 1 1 1 1

Question 4

Which quantities a, b, c, and d are required to balance this equation:

aFe₂O_3(s) + bCO_(g) ==> cFe_(l) + dCO_2(g)

A) 1 6 2 6

B) 2 3 4 6

C) 2 6 4 3

D) 1 3 2 3

Answer 4

D) 1 3 2 3

Question 5

Which quantities a, b, c, and d are required to balance this equation:

aAlBr_3(aq) + bCl_2(aq) ==> cAlCl_3(aq) + dBr_2(s)

A) 1 3 1 3

B) 2 3 2 3

C) 3 2 2 2

D) 1 3 2 2

Answer 5

B) 2 3 2 3

Question 6

Which quantities a, b, c, and d are required to balance this equation:

aFe_(s) + bO_2(g) ==> cFe₃O_4(s)

A) 3 4 1

B) 3 2 1

C) 6 2 2

D) 6 4 2

Answer 6

B) 3 2 1

Question 7

Which quantities a, b, c, and d are required to balance this equation:

aNa_(s) + bH₂O_(l) ==> cNaOH_(aq) + dH_2(g)

A) 1 2 1 2

B) 2 2 2 1

C) 1 1 1 2

D) 2 1 2 1

Answer 7

B) 2 2 2 1

Question 8

Which quantities a, b, c, and d are required to balance this equation:

aFe_(s) + bH₂O_(g) ==> cFe₃O_4(s) + dH_2(g)

A) 2 3 1 4

B) 3 4 1 4

C) 2 3 2 2

D) 3 4 1 2

Answer 8

B) 3 4 1 4

Question 9

Which quantities a, b, c, and d are required to balance this equation:

aCl_2(aq) + bCaI_2(aq) ==> cCaCl_2(aq) + dI_2(s)

A) 2 1 2 1

B) 2 2 1 2

C) 1 1 1 1

D) 1 2 2 2

Answer 9

C) 1 1 1 1

Question 10

Which quantities a, b, c, and d are required to balance this equation:

aC₅H_12(l) + bO_2(g) ==> cCO_2(g) + dH₂O_(l)

A) 2 8 10 12

B) 1 4 4 6

C) 1 8 5 6

D) 2 4 5 12

Answer 10

C) 1 8 5 6

Question 11

Which quantities a, b, c, and d are required to balance this equation:

aC₆H_14(g) + bO_2(g) ==> cCO_2(g) + dH₂O_(l)

A) 1 9 6 7

B) 2 9 6 14

C) 1 10 12 7

D) 2 19 12 14

Answer 11

D) 2 19 12 14

Question 12

Which quantities a, b, c, and d are required to balance this equation:

aFe₂O_3(s) + bHCl_(aq) ==> cFeCl_3(aq) + dH₂O_(l)

A) 1 6 2 3

B) 2 6 2 3

C) 1 6 2 6

D) 1 3 1 3

Answer 12

A) 1 6 2 3

Question 13

Which quantities a, b, c, and d are required to balance this equation:

aKOH_(aq) + bH₂SO_4(aq) ==> cK₂SO_4(aq) + dH₂O_(l)

A) 1 2 1 1

B) 2 1 1 2

C) 2 2 1 2

D) 1 1 1 1

Question 14

Which quantities a, b, c, and d are required to balance this equation:

aP_(s) + bCl_2(g) ==> cPCl_5(s)

A) 2 5 4

B) 2 5 2

C) 1 5 1

D) 1 5 2

Question 15

Which quantities a, b, c, and d are required to balance this equation:

aCu_(s) + bAgNO_3(aq) ==> cCu(NO₃)_2(aq) + dAg_(s)

A) 1 1 2 1

B) 1 2 1 2

C) 2 2 1 2

D) 2 2 2 1

Question 16

Which quantities a, b, c, and d are required to balance this equation:

aC₂H_6(g) + bO_2(g) ==> cCO_2(g) + dH₂O_(l)

A) 1 7 2 3

B) 1 2 1 3

C) 2 4 4 6

D) 2 7 4 6

Answer 16

D) 2 7 4 6

Question 17

Which quantities a, b, c, and d are required to balance this equation:

aAl_(s) + bHCl_(aq) ==> cAlCl_3(aq) + dH_2(g)

A) 2 3 2 3

B) 2 6 2 3

C) 1 6 3 2

D) 1 3 3 2

Answer 17

B) 2 6 2 3

Question 18

Which quantities a, b, c, and d are required to balance this equation:

aAl_(s) + bH₂O_(g) ==> cAl₂O_3(s) + dH_2(g)

A) 3 4 1 6

B) 2 3 1 3

C) 2 4 2 6

D) 1 3 1 3

Question 19

Which quantities a, b, c, and d are required to balance this equation:

aAl_(s) + bFe₂O_3(s)) ==> cAl₂O_3(s) + dFe_(s)

A) 1 2 2 1

B) 2 3 2 3

C) 2 1 1 2

D) 3 1 1 3

Question 20

Which quantities a, b, c, and d are required to balance this equation:

aAl_(s) + bCl_2(g) ==> cAlCl_3(s)

A) 1 3 1

B) 1 3 2

C) 2 3 2

D) 2 2 3

Question 21

Which quantities a, b, c, and d are required to balance this equation:

aC₇H_8(g) + bO_2(g) ==> cCO_2(g) + dH₂O_(l)

A) 2 9 4 8

B) 2 10 14 8

C) 1 5 7 4

D) 1 9 7 4

Question 22

Which quantities a, b, c, d, and e are required to balance this equation:

aCaCO_3(s) + bHCl_(aq) ==> cCaCl_2(aq) + dH₂O_(l) + eCO_2(g)

A) 1 1 1 1 1

B) 1 2 1 1 1

C) 2 1 2 2 2

D) 2 2 1 2 1

Question 23

Which of the following chemical formulas represents the reaction in which copper and oxygen combine to form copper oxide?

A) 2CuO ⇒ 2Cu + O₂

B) Cu + O₂ ⇒ 2CuO

C) 2Cu + O₂ ⇒ 2CuO

D) Cu + 2O₂ ⇒ 2CuO

Answer 23

C) 2Cu + O₂ ⇒ 2CuO

Question 24

Which of the following procedures would provide evidence for the law of conservation of mass?

A) Weigh the reactants, conduct the creation in an open container, and weigh the products.

B) Weigh the reactants, conduct the reaction in a sealed container, and weigh the products.

C) Measure the volume of the reactants, conduct the creation in a sealed container, and measure the volume of the products.

D) Write the chemical formula for the reaction and balance it.

Answer 24

C) Measure the volume of the reactants, conduct the creation in a sealed container, and measure the volume of the products.

Question 25

Hydrogen peroxide molecules are composed of two hydrogen atoms and two oxygen atoms. Water is also composed of hydrogen and oxygen, but water has one fewer oxygen atom than hydrogen peroxide does. Which of the following statements best describes the chemical reaction shown in the equation below:

2H₂O₂ ⇒ 2H₂O + O₂

A) Hydrogen peroxide is being made out of water and air.

B) Hydrogen peroxide is decomposing into pure water.

C) Hydrogen peroxide is decomposing into water and oxygen.

D) Water and oxygen are combining to make hydrogen peroxide.

Answer 25

C) Hydrogen peroxide is decomposing into water and oxygen.

Question 26

A chemical equation shows:

A) elements and mixtures

B) hydrogen and oxygen

C) chemical bonds

D) reactants and products

Answer 26

D) reactants and products

Question 27

A chemical equation can be balanced by changing the

A) reactants

B) products

C) coefficients

D) formulas

Answer 27

C) coefficients

Question 28

Which of the following is a balanced equation?

A) Zn + HCl ⇒ ZnCl₂ + H₂

B) H₂O ⇒ H₂ + O₂

C) Mg + 2 HCl ⇒ MgCl₂ + H₂

D) H₂SO₄ + NaOH ⇒ Na₂SO₄ + H₂O

Answer 28

C) Mg + 2 HCl ⇒ MgCl₂ + H₂

Question 29

What is the formula of the molecule?

A) C₂H₆O₃

B) C₃H₆O₂

C) C₅H₆O

D) ₃C₆H₂O

Answer 29

B) C₃H₆O₂

Question 30

The formula for copper sulfate is CuSO₄. What is the ratio of Cu : S : O atoms in the formula?

A) 1:3:4

B) 1:1:4

C) 1:4:4

D) 4:4:4

Answer 30

B) 1:1:4