Exam 1 Flashcards
(17 cards)
A beaker of water is heated from 80 degrees C to 110 degrees C. What is true about this process?
- Covalent bonds are formed
- Covalent bonds are broken
- Intermolecular forces are formed
- Intermolecular forces are overcome
a) 1
b) 2
c) 3
d) 4
e) 1 and 3
f) 2 and 4
d) 4
which of the following substances would you expect to have the highest boiling point?
a) CH4
b) OF2
c) CH3OCH3
d) CH3OH
d) CH3OH
which of the following systems will have higher entropy after mixing?
- 2 dye molecules and 2 water molecules
- 1 dye molecule and 3 water molecules
a) 1, because there are more possible arrangements of 1 than 2 after mixing
b) 2, because there are more possible arrangements of 2 than 1 after mixing
c) 1, because there are fewer possible arrangements of 1 than 2 after mixing
d) 2, because there are fewer possible arrangements of 2 than 1 after mixing
a) 1, because there are more possible arrangements of 1 than 2 after mixing
an aqueous solution A is prepared by dissolving 0.1 mol potassium chloride [KCl] and 0.1 mol sodium nitrate [NaNO3] in water to make 1.0 L of solution. An aqueous solution B is prepared by dissolving 0.1 mol potassium nitrate [KNO3] and 0.1 mol sodium chloride [NaCl] in water to make 0.1 L of solution. Which statement is true?
a) since the molar masses of the salts are different, the solutions must also be different
b) solution A will conduct electricity and solution B will not conduct electricity
c) solution A is identical to solution B
d) the total ion concentration in solution B is greater than the total ion concentration in solution A
c) solution A is identical to solution B
A solution is prepared by dissolving 3.4 grams of NH3 in enough water to make 2.0 L of solution. What is the molarity of the solution?
a) 1.7 M
b) 0.59 M
c) 0.20 M
d) 0.10 M
d) 0.10 M
Which of these statements are true about the process of freezing water?
- delta S system is positive
- delta S system is negative
- it is exothermic
- it is endothermic
a) 1 and 3
b) 2 and 3
c) 1 and 4
d) 2 and 4
b) 2 and 3
in a liquid sample of HCl, what bonds/interactions would you expect to be present between molecules?
- London Dispersion Forces
- Dipole-Dipole interactions
- Hydrogen bonding interactions
- Covalent bonds
a) 1 only
b) 1 and 2
c) 1 and 4
d) 1, 2, and 3
e) 1, 2, and 4
f) none - HCl is always a gas
b) 1 and 2
Which of these statements are true about the energy changes during bond formation and bond breaking?
- bond breaking releases energy to the surroundings
- bond breaking absorbs energy from the surroundings
- bond formation releases energy to the surroundings
- bond formation absorbs energy from the surroundings
a) 1 and 3
b) 1 and 4
c) 2 and 3
d) 2 and 4
c) 2 and 3
Federal regulations limit the concentration of lead [Pb] in drinking water to 15 ppb. Recently, scientists from Virginia Tech reported some water samples of drinking water in Flint, Michigan had lead levels of 6.4 x 10^-5 M. What is the concentration of lead in this water sample using units of parts per billion [ppb]?
a) 13200 ppb
b) 6400 ppb
c) 64 ppb
d) 0.0132 ppb
a) 13200 ppb
what is the evidence that dissolving CaCl in water is an endothermic process?
a) the temperature of the solution increases
b) the temperature of the solution decreases
c) the solute-solvent interactions are stronger than the solvent-solvent and solute-solute interactions
d) the solvent-solvent and solute-solute interactions are stronger than the solute-solvent interactions
b) the temperature of the solution decreases
a solute is insoluble in water. a calculation is done to estimate that the strength of interactions broken is about the same as the strength of interactions formed. Which of these statements must be true?
a) the entropy of the system would increase
b) the entropy of the system would decrease
c) the enthalpy change would increase if the water were heated
d) the enthalpy change would decrease if the water were heated
b) the entropy of the system would decrease
Which of the following processes would you predict to have the most negative delta S for the system
a) Gas –> liquid
b) Gas –> solid
c) Liquid –> solid
d) Liquid –> gas
e) Solid –> liquid
f) Solid –> gas
b) Gas –> solid
why does thermal energy travel from a hot block to a cold block when they touch?
a) because the energy quanta have a greater number of possible arrangements when there are more quanta in one block than the other
b) because the thermal energy prefers to spread out across as many atoms as possible
c) because there are more possible arrangements for the energy quanta when equally spread across both blocks
d) because the hot block has too much energy
e) because it is simply more probable to have an uneven distribution of thermal energy for the two blocks
c) because there are more possible arrangements for the energy quanta when equally spread across both blocks
when a salt dissolves in water, what is the system?
- the salt ions
- the water molecules directly surrounding the ions
- the water that is not directly surrounding the ions
a) 1 only
b) 1 and 2
c) 2 only
d) 1, 2, and 3
e) 3 only
b) 1 and 2
a process happens within a system. This process results in a decrease in the entropy of the system. Which of the following statements must also be true?
- delta G is negative
- delta G is positive
- delta S for the surroundings is negative
- delta S for the surroundings is positive
a) 1 and 3
b) 1 and 4
c) 2 and 3
d) 2 and 4
b) 1 and 4
two wires connected to a battery and a light bulb are dipped into a beaker of water. No current flows, so the bulb remains unlit. A substance is added to the water and the light bulb turns on. Which substance was added and why does the light bulb light up?
1. CH4
2. KCl
because
3. the compound dissolves into the water and electrons are free to move in the solution to the electrodes
4. the compound dissolves into the water and ions are allowed to move in solution to the oppositely charged electrode
a) 1 and 3
b) 1 and 4
c) 2 and 3
d) 2 and 4
d) 2 and 4
a 10.0 mL sample of a 0.50 M solution of NaOH is added to a 500 mL volumetric flask. The flask is then filled to the mark with water. What is the concentration of the resulting solution?
a) 1.0 M
b) 0.05 M
c) 0.025 M
d) 0.01 M
d) 0.01 M
