AP Chemistry Unit 3 Review

Molarity CalculationsM=moles/Liter

100

Calculate the molarity of a solution containing          3.0 moles of NaCl in 1.2 liters of solution. 

3/1.2 = 2.5 M

200

What is the molarity of a solution with 0.50 moles of solute in 250 mL of solution? 

2.0 M

300

How many grams of potassium carbonate (K₂CO₃) are needed to make 200 mL of a 2.5 M solution? 

69.1 grams

400

What is the concentration of a solution with a volume of 660 mL that contains 33.4 grams of aluminum acetate, Al(C₂H₃O₂)₃ ?

0.25 M

500

How many liters of a 0.88 M solution can be made with 25.5 grams of lithium fluoride? 

1.11 liters

Wavelength & FrequencyCalculations c = yv & E = hv

100

What is the relationship between wavelength and frequency in the EM spectrum? 

Inverse relationship, wavelength long = low frequency - wavelength short = high frequency

200

The wavelength of a green light from a traffic signal is centered at 5.20 X 10^-5 cm. (convert cm to meters first). Calculate the frequency.

5.77 X 10¹⁴ Hz

300

Calculate the wavelength of light that has a frequency of 1.5 X 10¹⁵ Hz?

2.0 X 10^-7 m

400

How much energy does light with a wavelength of 695 nm have? (convert nm to meters first)

E = 2.86 X 10^-19 J

500

Calculate the energy and frequency of red light having a wavelength of 6.80 X 10^-5 cm. (convert cm to meters first)

wavelength = 4.4 X 10¹⁴ Hz

Energy = 2.92 X 10^-19 J

Ideal Gas Law: PV = nRT (R = 0.0821 (L• atm/mol•K)

100

Determine the volume of occupied by 2.34 grams of carbon dioxide gas at STP. (at STP, P= 1.0 atm and T = 273 K)

V = 1.19 L (to three significant figures) 

200

A sample of argon gas at STP occupies 56.2 liters. (at STP, P = 1.0 atm and T=273 K)             Determine the following:

#1- the number of moles of argon and    

#2 -the mass of argon in the sample.                      (at STP, P = 1.0 atm and T=273 K)

2.51 mol 

2.51 moles X 39.948 g/mol = 100. g (to 3 sig figs)

300

At what temperature will 0.654 moles of neon gas occupy 12.30 liters at 1.95 atmospheres? 

T = 447 K 

400

What do the variables stand for in the Ideal Gas Equation? What are their most common units?

P = pressure of the gas (atm)

V = volume of the gas (L)

n = number of moles of gas (mol)

R = gas constant (0.0821 L-atm/mol K

T = absolute temperature of the gas (K)

500

A 22.0 gram sample of an unknown gas occupies 11.2 liters at standard temperature and pressure. Which of the following could be the identity of the gas? (at STP, P = 1.0 atm and T=273 K)

A) CO₂        B) SO₃      C) O₂      D) He

CO_{2 (since molar mass = 44 g/mol)}

Types of Solids

100

What are the four types of solids?

Ionic, Covalent Network, Molecular, and Metallic

200

Which type of solids have high melting points, is very brittle and is a very good conductor of electricity as liquids? (Ex: NaCl)

Ionic solids

300

Which type of solids have very high melting points, are very hard, but do not conduct electricity? 

(Ex: Diamonds)

Covalent Network Solids

400

This type of solid has variable to high melting points, is malleable, and conductive (consists of metal cations in a sea of delocalized electrons - Ex: Gold)

Metallic Solids

500

What type of solids have low melting points, are soft, and not conductive (Ex: CO₂)

Molecular Solids

IMFs

100

List all the intermolecular forces between two O₂ molecules.

London Dispersion forces only (O₂ is nonpolar)

200

List the IMF's in order of increasing strength. 

Ionic bonding

Hydrogen bonding

London Dispersion forces

Dipole-Dipole

London Dispersion, Dipole-Dipole, Hydrogen Bonding, Ionic Bonding

300

Which molecule would have the higher boiling point and why: NH₃ or CH₄?

NH₃ because it is polar and has D-D forces and H-Bonding, while CH₄ is nonpolar and only has weaker LDF between its molecules

400

Which has stronger IMFs and why: Cl₂ or Br₂?

Br₂ because it has more electrons than Cl₂ and is therefore more polarizable. Both molecules are nonpolar and only have LDF, but the more polarizable the atom, the stronger the LDF.

500

You have two sealed jars. One has liquid Br₂ and the other has liquid H₂O. Which jar would you expect to have more molecules in the gaseous state after 10 minutes and why?

Br₂ because it only has LDF (nonpolar molecules). H₂O has stronger hydrogen bonding so the molecules will be more likely to remain in the liquid form.