Molarity Calculations
M=moles/Liter
M=moles/Liter
Calculate the molarity of a solution containing 3.0 moles of NaCl in 1.2 liters of solution.
3/1.2 = 2.5 M
Inverse relationship, wavelength long = low frequency - wavelength short = high frequency
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)
What are the four types of solids?
Ionic, Covalent Network, Molecular, and Metallic
What is the molarity of a solution with 0.50 moles of solute in 250 mL of solution?
2.0 M
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
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)
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
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
How many grams of potassium carbonate (K2CO3) are needed to make 200 mL of a 2.5 M solution?
69.1 grams
Calculate the wavelength of light that has a frequency of 1.5 X 1015 Hz?
2.0 X 10-7 m
At what temperature will 0.654 moles of neon gas occupy 12.30 liters at 1.95 atmospheres?
T = 447 K
Which type of solids have very high melting points, are very hard, but do not conduct electricity?
(Ex: Diamonds)
Covalent Network Solids
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
How much energy does light with a wavelength of 695 nm have? (convert nm to meters first)
E = 2.86 X 10-19 J
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)
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
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.
How many liters of a 0.88 M solution can be made with 25.5 grams of lithium fluoride?
1.11 liters
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
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
CO2 (since molar mass = 44 g/mol)
What type of solids have low melting points, are soft, and not conductive (Ex: CO2)
Molecular Solids