7.3, 7.4, & Chapter 8

Question 1

Will the compound FeCl₃ dissolve in water? How can you tell?

Answer 1

Yes. Looking at the solubility chart on the periodic table, iron(III) chloride shows (aq), meaning that putting the compound in water results in an aqueous solution of it - it dissolves in water.

Question 2

A solid that is produced as a result of a chemical reaction in solution and that separates from the solution.

Answer 2

Precipitate

Question 3

Will the following reaction proceed as written? Explain.

Ca + Cu(NO₃)₂ –> Cu + Ca(NO₃)₂

Answer 3

Yes. Since calcium is above copper in the activity series, it will replace it.

Question 4

A list of elements organized according to the ease with which the elements undergo certain chemical reactions.

Answer 4

Activity Series

Question 4

Will the following reaction proceed as written? Explain.

AgBr + I₂ –> AgI + Br₂

Answer 4

No. Since the halogen iodine is below the halogen bromine on the periodic table, it is less active and will not replace it.

Question 5

Will the compound MgO dissolve in water? How can you tell?

Answer 5

No. Looking at the solubility chart on the periodic table, magnesium oxide shows (s), meaning that, when placed in water, the compound remains solid - it does not dissolve.

Question 5

Show the net ionic equation for the following reaction. You must first predict the products, balance the equation, and determine the solubilty of the products.

K₂S (aq) + Zn(NO₃)₂ (aq) –>

Answer 5

Question 6

A reaction in which a single compound produces two or more simpler substances:

AB –> A + B

ONLY ONE REACTANT

Answer 6

Decomposition Reaction

Question 7

The seven diatomic elements are… (the mnemomic device is Have No Fear Of Ice Cold Beverages)

Answer 7

H₂, N₂, O₂, F₂, Cl₂, Br₂, I₂

Question 8

The separation of ions that occurs when an ionic compound dissolves.

Answer 8

Dissociation

Question 9

Ions that do not take part in a chemical reaction and are found in solution both before and after the reaction.

Answer 9

Spectator ions

Question 9

When balancing chemical equations, the only things that may be changed are the…

Answer 9

Coefficients

Question 10

The symbols written after a substance in a chemical equation to indicate solid, liquid, gas, or aqueous, respectively.

Answer 10

(s), (l), (g), (aq)

Question 10

When a solid is dissolved in water, it is this type of solution.

Answer 10

Aqueous

Question 12

A chemical reaction in which the products re-form the original reactants.

Answer 12

A reversible reaction

Question 14

States that atoms are neither created nor destroyed in a chemical reaction; they are only rearranged.

Answer 14

The Law of Conservation of Mass

Question 15

A small whole number that appears in front of a formula in a chemical equation.

Answer 15

A coefficient

Question 16

A reaction in which a substance combines with oxygen, releasing a large amount of energy.

When involving a hydrocarbon, the products are always carbon dioxide and water:

C_xH_y +O₂ –> CO₂ + H₂O

Answer 16

Combustion Reaction

Question 17

The symbol shown here means…

Answer 17

Heat is added to drive a reaction

Question 18

What type of reaction is shown below? Predict the products and then balance.

Cd(s) + AgC₂H₃O₂(aq) –>

Answer 18

Single Displacement

Cd(s) + 2AgC₂H₃O₂(aq) –>2Ag(s) + Cd(C₂H₃O₂)₂(aq)

Question 20

A reaction in which one element replaces a similar element in a compound.

A + BC –> B + AC

Answer 20

Single Replacement

Question 21

What type of reaction is shown below? Predict the products and then balance.

Na₂SO₄(aq) + Ba(NO₃)₂(aq) –>

Answer 21

Double Displacement

Na₂SO₄(aq) + Ba(NO₃)₂(aq) –> 2NaNO₃(aq) + BaSO₄(s)

Question 22

Uses symbols and formulas to represent the identities and relative molecular or molar amounts of the reactants and products in a chemical reaction.

Answer 22

Chemical equation

Question 23

What type of reaction is shown below? Predict the products and then balance.

C₁₀H₂₂(s) + O₂(g) –>

Answer 23

Combustion

2C₁₀H₂₂(s) + 31O₂(g) –> 20CO₂(g) + 22H₂O(g)

Question 24

The symbol shown here means...

Answer 24

A reversible reaction.

Question 25

What type of reaction is shown below? Predict the products and then balance. Ag₂O(s) --\>

Answer 25

Decomposition 2Ag₂O(s) --\> 4Ag(s) +O₂(g)

Question 26

A reaction in which two or more substances combine to form a new compound. A + B --\> AB ONLY ONE PRODUCT

Answer 26

Synthesis Reaction

Question 27

A chemical equation is balanced when...

Answer 27

The same number of atoms appear on both sides of the arrow.

Question 29

A substance that changes the rate of a chemical reaction but can be recovered unchanged.

Answer 29

Catalyst

Question 30

What type of reaction is shown below? Predict the products and then balance. Na(s) + F₂(g) --\>

Answer 30

Synthesis 2Na(s) + F₂(g) --\> 2NaF(s)

Question 31

An equation that includes only those compounds and ions that undergo a chemical change in a reaction in aqueous solution.

Answer 31

Net ionic equation

Question 32

Four easily observed changes that usually indicate a chemical reaction has occurred.

Answer 32

1. Color Change 2. Release/Absorption of energy (usually heat) 3. Production of a gas 4. Formation of a precipitate

Question 33

A reaction in which the ions of two compounds exchange places in an aqueous solution to form two new compounds. AB + CD --\> AD + CB

Answer 33

Double Displacement

Question 34

The symbol shown here means...

Answer 34

A catalyst was used to speed up the reaction (specifically platinum in this case, but could be other substances).

Question 35

The → symbol means...

Answer 35

Yields

Question 36

The suggested steps for balancing equations are...

Answer 36

1. Balance atoms that appear only once on either side of the arrow first 2. Balance everything except hydrogen and oxygen 3. Balance hydrogen 4. Balance oxygen

Question 37

Tetracycline is an antibiotic used in the treatment of acne and rosacea. The compound is 59.46% carbon, 5.44% hydrogen, 6.30% nitrogen, and 28.80% oxygen. Calculate the empirical formula of this compound. In a separate experiment, the molecular mass of tetracycline was determined to be 444.432u. What is its molecular formula?

Answer 37

Question 38

A certain compound consists only of sulfur and nitrogen. The mass composition for this compound was found to be 69.6% sulfur and the remainder nitrogen. What is the empirical formula of this compound? If the molecular mass of the compound was found to be 184.32u, what is its molecular formula?

Answer 38

Question 39

When taking x-rays of the upper gastrointestinal tract, a patient is given a barium swallow as a contrast medium. The suspension of barium sulfate coats the upper GI tract with barium, enhancing its visibility on the x-ray. What is the mass composition of each element in barium sulfate, to two decimal places?

Answer 39