Final Exam Review

Exam 1

100

Identify the number of protons and electrons for the following: C, C-, C+

C= 6 protons, 6 electrons ; C-= 6 protons, 7 electrons ; C+= 6 protons, 5 electrons

200

Draw two illustrations: One representing an ionic compound and one representing a molecular compound. Explain your drawing

Ionic-metal and nonmetal Molecular-two or more nonmetals

300

Determine the solubility of the following compounds and the major species present: 1. (NH4)2S : 2. Ca(OH)2 : 3. CaS :

1. Soluble (aq); major species, 2NH4+ (aq) , S^2- (aq) : 2. Soluble (aq); major species, Ca^2+ (aq) , 2OH- (aq) : 3. Insoluble (s); major species, CaS(s

400

A sample of C6H14O3 contains 0.150 moles ofC6H14O3. How many grams of O are present?

7.196g

Exam 2

100

What is a limiting reactant?

The reactant in a chemical reaction that limits the amount of product that can be formed. The reaction will stop when all of the limiting reactant is consumed.

200

Which of the following species has the most unpaired electrons? S+, S, or S-

S+

300

Indicate whether this is true or false and explain: When carbon monoxide gas reacts with oxygen gas to form carbon dioxide gas, the number of gas molecules present decreases.

True ; 3 gas molecules to two gas molecules ; 2 CO(g) + O2 (g) -> 2CO2 (g)

400

Describe how you would prepare 250mL of a 0.10M solution of HCl from the 6.0M stock solution.

Calculate the dilution M1V1=M2V2 and get 4.167mL ; Measure out 4.167 mL of the 6.0M stock solution. Transfer it to an Erlenmeyer flask and add water until it reaches the 250mL mark, stir

Exam 3

100

What are the steps you would take to draw a Lewis Structure?

1.Place the least electronegative element in the center (Not Hydrogen). Arrange the others around it 2.Connect the atoms with bonds and add electrons (don’t forget the octet rule) 3.To decide which arrangement is more favorable use formal charge

200

What is exothermic? What is endothermic? What chemically happens with bonds that are breaking/making bonds? What are the values of ΔH?

Exothermic-formation of chemical bonds, releases energy from the system into the surroundings, ΔH is negative ; Endothermic-breaking chemical bonds, requires energy going into system, ΔH is positive

300

What is Average Valence Electron Energy (AVEE)?

AVEE- a measure of how tightly an atom holds its valence electrons

400

Indicate wether the following statement is true or false and explain your answer: An atom with a larger AVEE will have a partial negative charge.

True. The atom with the larger value of AVEE will have the partial negative charge. This is because a larger AVEE means the electrons are being pulled closer to the nucleus. Electrons have a negative charge, which makes the atom with a larger AVEE partially negative.

Random

100

Balance the following equation: ___N2 + ___H2 -> ____ NH3

N2+ 3 H2 -> 2NH3

200

What is formal charge and what is it used for?

•Formal charge = core charge – number of assigned electrons; =core charge – (lines + dots) •Formal charge is used to help determine the best Lewis structure based on partial charges

300

Write the chemical name for CO. Explain your answer.

Carbon Monoxide

400

What is the difference between intra and inter molecular forces?

Intramolecular forces-within a molecule Intermolecular forces-between molecules