ACHM115 Exam 2 Review

Chapter 2: Nomenclature and molecules

100

What are the seven diatomic molecules that exist in nature?

Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Bromine, and Iodine

200

What is the formula for the following ionic compound:

Ca²⁺ and NO₃^-

(I will re-write the ions on the board if needed.)

Ca(NO₃)₂ (Calcium Nitrate)

300

What is the name of the following molecule according to binary nomenclature: 

XeF₆

XeF₆: Xenon Hexafluoride

400

Name the following molecule based on oxyanion nomenclature: 

Na₂SO₃

Na₂SO₃: Sodium Sulfite

500

What is the name of this acid and its anion:

H₃PO₄ and PO₄^3-

(I will re-write the molecules on the board if needed.)

H₃PO₄: Phosphoric acid 

PO₄^3-: Phosphate

(1) Chapter 3: % Composition, Molar conversions, EF, Molarity, and dilutions

100

What is the percent composition of P in Ca₃(PO₄)₂? Round to two decimal places.

19.97%

200

How many grams is in 0.114 mol of K₂SO₄?

19.9 grams

300

Mercury (Hg) forms a compound with chlorine (Cl) that is 73.9% mercury and 26.1% chlorine by mass. What is the empirical formula?

(From ChemLibre)

HgCl₂

400

A 0.885 M solution of KBr whose initial volume is 76.5 mL has more water added until its concentration is 0.500 M. What is the new volume of the solution?

(From ChemLibre)

135 mL

500

How many moles of sucrose, C₁₂H₂₂O₁₁, are present in a 135 mL 1.5 M solution?

0.203 mol sucrose

(2) Chapter 3:% Composition, Molar conversions, EF, Molarity, and dilutions

100

What is the percent composition of O in penicillin, C₁₂H₁₈N₂O₄S? Round your answer to two decimal points. 

22.35%

200

How many moles are present in 782g of Fe₂O₃?

4.90 mol Fe₂O₃

300

A compound is composed of 52.14% Carbon, 13.13% Hydrogen, and 34.73% Oxygen. What is the empirical formula?

(From Organic Chemistry Tutor)

C₂H₆O

400

If 25.0 mL of a 2.19 M solution are diluted to 72.8 mL, what is the final concentration?

(From ChemLibre)

0.752 M

500

How many moles of NaCl are present in a 215 mL 1.33 M solution?

0.286 mol NaCl

(1) Chapter 4: Solubility/dissociation, A+B, ionic equations, types of reactions, oxi. #, and limiting reagent

100

True or false: Strong acids and bases partially dissociate in water depending on how many hydrogens present.

False. Strong acids and bases fully dissociate in water regardless of how many hydrogens it has.

200

Which of the following IS NOT a strong acid?

HCl, HF, and HBr

HF. HF is not a strong acid because F is too electronegative to fully dissociate in water.

300

Write the complete ionic equation of MgSO₄...

(Full reaction will be shown on paper.)

Full answer will be shown on paper.

400

What is the oxidation number of the chromium ion, Cr, in CrCl₃

The oxidation number of the chromium ion, Cr, in the compound is 3+.

500

Write a balanced equation for the decomposition reaction when solid magnesium carbonate is heated.

Hint: two products form (a solid and a gas)

Full answer will be shown on paper

(2) Chapter 4: Solubility/dissociation, A+B, ionic equations, types of reactions, oxi. #, and limiting reagent

100

What does it mean to dissociate? 

When ionic compounds and molecules break apart into ions.

200

Which of the following compounds are insoluble?

HCl, AgCl, and LiCl

AgCl

300

What type of reaction is shown below: 

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

Combustion reaction. Many combustion reactions involve hydrocarbons reacting with oxygen to form carbon dioxide and water.

400

What type of reaction is shown below:

HCl (aq) + KOH (aq) -> KCl (aq) + H₂O (l)

Neutralization reaction. Reaction between an acid in solution and a base in solution to form a salt and water as a product. A salt is defined as a compound formed from a cation and an anion with a neutral overall charge.

500

Calculate the mass of MgO possible if 2.40g of Mg reacts with 10.0g of O₂.

Mg + O₂ -> MgO

(From ChemLibre)

3.98g MgO