70 terms

Chemistry Pre-AP

Just a review based on the tests for my Chemistry Pre-AP Class
If the temperature of a fixed quantity of gas decreases and the pressure remains unchanged
its volume decreases
What is the value of the gas constant?
0.0821 L*atm
Which substance has the lowest density
Hg(g) Hg(l) H2O(g) H2O(l)
The kinetic-molecular theory explains the properties of solids, liquids, and gases in terms of the energy of the particles and
the forces that act between the particles
According to the kinetic-molecular theory, gases condense into liquids because of
forces between molecules
Suppose that two gases with unequal molar masses were injected into opposite ends of a long tube at the same time and allowed to diffuse toward the center. They should begin to mix
closer to the end that held the heavier gas
If gas A has a molar mass greater that that of gas B and samples of each gas at identical temperatures and pressures contain equal numbers of molecules, then
the volumes of gas A and gas B are equal
To correct for partial pressure of water vapor, the vapor pressure of H2O at the collecting temperature is
subtracted from the total gas pressure
Unlike in an ideal gas, in a real gas
the particles exert attractive forces on each other
If the height of mercury in a barometer at 0*C is less than 760mmHg, then
the atmospheric pressure is less than standard
For reactants and products that are gases, the coefficients in the chemical equation indicate
According to Avogadro's law, 1 L of H2(g) and 1 L of O2(g) at the same temperatures and pressure
contain equal numbers of molecules
According to Graham's Law, two gases at the same temperature and pressure will have different rates of diffusion because they have different
molar masses
Why does a can collapse when a vacuum pump removes air from the can?
The unbalanced outside force from atmospheric pressure crushes the can
Which is an example of effusion?
a. oxygen and gasoline fumes mixing in an automobile carburetor
b. air slowly escaping from a pinhole in a tire
c. the aroma of a cooling pie spreading across a room
d. helium dispersing into a rooms after a balloon pops
What determines the average kinetic energy of the molecules of any gas?
If the pressure and temperature of a gas are held constant and some gas is added to the container or some is allowed to escape, a change in which of the following can be observed?
a. kinetic energy b. fluidity
c. volume d. elasticity
When does a real gas behave like an ideal gas?
when the particles are far apart
If a gas with an odor is released in a room, it quickly can be detected across the room because it
Why does the air pressure inside the tires of a car increase when the car is driven?
the air particles inside the tire increase their speed because their temperature rises
Which of the following pairs of solutions produces a precipitate when combined?
a. Cu(NO3)2 and NaCl
b. Fe(NO3)3 and MgCl2
c. Cu(NO3)2 and K2CO3
d. CaCl2 and NaNO3
When solutions of NH4OH and K2SO4 are combined, what precipitate(s) forms?
Stirring increases the rate of dissolution because it
brings fresh solvent into contact with the solute
Which of the following is a heterogeneous mixture?
a. water
b. a sugar-water solution
c. whole wheat bread
d. sugar
What is the boiling point elevation of a solution made from 10.0g of a nonelectrolyte solute and 300.0g of water? (The molar mass of the solute is 50.0g and the molal boiling point constant for water is 0.51*C/m).
How many moles of HCl are present in 0.70 L of a 0.33M HCl solution? (molar mass of HCl = 36.46g/mol)
0.23 mol
Which of the following is a strong electrolyte?
a. HC2H3O2 b. HBr
c. HF d. NH3
The solubility of ethanol, CH3CH2OH, molecules in water is enhanced by
hydrogen bonding between the solute and solvent molecules
The formula for the hydronium ion is
All of the following are heterogeneous mixtures EXCEPT
a. whole wheat bread
b. granite
c. tap water
d. an oil-water mixture
Which of the following decreases the average kinetic energy of solvent molecules?
a. decreasing the pressure
b. not stirring the solution
c. decreasing the contact area between the solvent and the solute
d. decreasing the temperature
The Tyndall effect is used to distinguish between
solutions and colloids
Which of the following values for enthalpy of solution at 25*C represents the greatest release of energy?
a. -3.50 kJ/mol b. -0.01 kJ/mol
c. 1.33 kJ/mol d. 12.40 kJ/mol
The separation of ions that occurs when an ionic compound dissolves is called
In the expression "like dissolves like", the word like refers to similarity in molecular
The concentration of a water solution of NaCl is 2.48 m, and it contains 806g of water. How much NaCl is in the solution? (molar mass of NaCl = 58.44 g/mol)
117 g
Increasing the surface area of the solute
increases the rate of dissolution
An endothermic dissolution process
absorbs energy are heat and has a positive enthalpy of solution
Which of the following is an ionic compound the dissociates in water?
a. NaCl b. Cl2
c. HCl d. C6H6
In a solution, the slightly charged part of a water molecule
forms ionic bonds with ions in ionic compounds
Pressure has the greatest effect on the solubility of
gases in liquids
Nonvolatile solutes
depress the freezing point and elevate the boiling point
What is the molarity of a solution that contains 31.0g HCl in 5.00 kg water? (molar mass of HCl = 36.46 g/mol)
0.170 m
Which compound dissociates to produce the ions SO4^-2(aq) amd NH4^+(aq)?
Which of the following is a weak electrolyte?
a. hydrogen chloride b. sugar
c. sodium chloride d. acetic acid
How many moles of ions are produced by the dissociation of 0.5 mol of Na2CO3?
1.5 mol
Which mixture contains visible particles that settle out unless the mixture is stirred?
Which of the following is a molecular substance whose aqueous solution carries an electric current?
a. liquid hydrogen b. hydrogen chloride
c. sugar d. iron
hydrogen chloride
Which of the following will dissolve most rapidly?
a. sugar cubes in cold water
b. sugar cubes in hot water
c. powdered sugar in cold water
d. powdered sugar in hot water
How many milliliters of a 0.171 M solution contain 1.00 g of NaCl? (molar mass of NaCl = 58.44 g/mol)
100. mL
Molecular substance contain
either polar-covalent or nonpolar-covalent bonds
Which of the following is the right side of the equation for dissolving K2S(s)?
2K+(aq) + S^-2(aq)
As temperature increases, solubility of solids in liquides
usually increases
Electrolytes have a greater effect on freezing point depression than nonelectrolytes because electrolytes
produce more moles of solute per mole of solvent
How many moles of ions are produced by the dissociation of 1 mol of Al2(CO3)3?
5 mol
Which of the following is an example of a polar solvent?
a. carbon tetrachloride b. benzene
c. water d. gasoline
The freezing point of an aqueous solution that contains a nonelectrolyte is -8.0C. What is the molal concentration of the solution. (The molal freezing point constant for water is -1.86C/mol)
4.3 m
Which of the following is an electrolyte?
a. sodium chloride b. sugar
c. pure water d. glass
Which of the following expresses concentration?
a. molality
b. molarity
c. moles of solute per liter of solution
d. all of the above
Which of the following is a nonelectrolyte?
a. sodium chloride b. hydrogen chloride
c. sugar d. potassium chloride
In a solution at equilibrium
the rate of dissolution and the rate of crystallization are equal
Compared with a 0.01 m sugar solution, a 0.01 m MgCl2 solution has
about three times the freezing point depression
A 15 M acetic acid solution is
a concentrated and weak electrolyte
Which of the following is soluble in water?
a. potassium nitrate
b. silver
c. benzene
d. carbon tetrachlroide
As temperature increase, solubility of gases in liquids
What is the molarity of a solution that contains 125 g NaCl in 4.00 L solution? (molar mass of NaCl = 58.44 g/mol)
0.535 M
Raising solvent temperature cause solvent-solute collisions to become
more frequent and more energetic
Which of the following is a molecular compound that ionizes in water?
a. NaCl b. Cl2 c. HCl d. C6H6
The hydrogen ion
is a proton
A solute crystal is dropped into a solution containing dissolved solute. It falls to the bottom of the beaker and does not dissolve after vigorous stirring. What does this indicate about the solution?
it is probably supersaturated