Ch. 6 Chem and Society
Charles's Law relates the volume and temperature of a gas sample at constant pressure. What would be the temperature of a gas sample when its volume is 0 L?
-273°C
The temperature at which a liquid boils is the boiling point of the liquid. The boiling point is an indication of the intermolecular forces that hold the matter in the liquid state. Water, H2O, boils at 100°C. Ethanol, C2H6O boils at 78°C. Ammonia, NH3, boils at -33°C. Which one of the following ranks the intermolecular forces in these liquids from the strongest to the weakest?
Water > Ethanol > Ammonia
The temperature at which a liquid becomes a gas is called the
boiling point
Which of the following processes involves the removal of energy (heat)?
condensation
gas to liquid
condensation
What is the predominant force between IBr molecules in liquid IBr?
dipole forces
Liquid hydrogen is used as one part of the booster fuel in the space shuttle. What type of forces exist between hydrogen molecules in liquid hydrogen?
dispersion forces
What type of forces exist between oxygen molecules in liquid oxygen?
dispersion forces
Which of the following is the weakest?
dispersion forces
liquid to gas
evaporation
A covalent bond is weaker than a hydrogen bond.
false
A solution is a heterogeneous mixture.
false
Temperatures must be converted to the Celsius temperature scale when Charles's Law is used.
false
liquid to solid
freezing
Matter is more likely to exist in the ________ state as the pressure is reduced.
gas
Matter is more likely to exist in the ________ state as the temperature is raised.
gas
Which physical state is most highly disordered?
gas
Which state of matter is characterized by having molecules far apart and moving randomly
gas
The kinetic-molecular theory of gases assumes which of the following?
gas molecules move constantly and in straight lines
A liquid
has a definite volume but no definite shape.
A gas
has no definite shape and no definite volume.
Which of the following is NOT a property of an ionic compound? Ionic compounds generally
have melting points lower than those of molecular compounds.
The attraction between an ion and water molecules is
ion-dipole interaction.
Which state of matter is characterized by having molecules close together, but moving randomly
liquid
) Vaporization is the change from the ________ state to the ________ state.
liquid to gas
The temperature at which a solid becomes a liquid is called the
melting point
Matter is more likely to exist in the ________ state as the pressure is increased.
solid
Matter is more likely to exist in the ________ state as the temperature is lowered
solid
The degree of order of matter is directly proportional to the cohesive forces that hold the matter together. In other words, the more organized the state of matter, the stronger the "glue" that holds it together. Given the above, which one of the states has the strongest cohesive forces?
solid
Which physical state is most highly ordered?
solid
Which state of matter is characterized by having molecules close together and confined in their movement
solid
The degree of order of matter is directly proportional to the cohesive forces that hold the matter together. In other words, the more organized the state of matter, the stronger the "glue" that holds it together. Which of the following ranks these cohesive forces from the state with the strongest to that with the weakest cohesive forces
solid > liquid > gas
Which of the following ranks the three states of matter from most to least ordered?
solid > liquid > gas
Ionic compounds have strong forces between particles. This means that generally ionic compounds are ________ at room temperature.
solids
The temperature at which a solid melts is the melting point of the solid. The melting point is an indication of the intermolecular forces that hold the solid together. Water melts at 0°C. Table sugar (sucrose) melts at 285°C. Gallium, Ga, melts at 30°C. Which one of the following ranks the intermolecular forces in these solids from the strongest to the weakest?
sucrose > Ga > water
When an ionic compound dissolves in water,
the negative ends of water molecules surround the positive ions.
In the ideal gas law equation, PV=nRT, R is known as
the universal gas constant
The pressure of a gas will increase when
the volume decreases
According to the kinetic-molecular theory, there is very little attraction between particles of a gas.
true
If the pressure of a gas rises, the gas molecules will strike the walls of its container more frequently. (Assume that the container has a definite shape and volume.)
true
It requires more energy to melt one mole of an ionic compound than one mole of a molecular compound.
true
The conditions for standard temperature and pressure (STP) are 1 atm pressure and 0°C.
true
The phrase "like dissolves like" means that a polar substance will dissolve most readily in a polar solvent.
true
According to the kinetic-molecular theory, gas molecules have
weak interaction between molecules
A balloon is inflated outdoors on a cold day in North Dakota at a temperature of -40°C to a volume of 2.00 L. The pressure remains constant. What is the volume of the balloon indoors at a temperature of 25°C?
2.6 L
The molar volume of a gas at STP is
22.4 L
A gas is enclosed in a 10.0 L tank at 1200 mm Hg pressure. Which of the following is a reasonable value for the pressure when the gas is pumped into a 5.00 L vessel?
2400 mm Hg
At STP, 22.4 liters of nitrogen gas, N2, will have a mass of
28 g
At STP, 22.4 liters of oxygen gas, O2, will have a mass of
32 g
Use the ideal gas law to calculate the volume occupied by 0.200 mol of nitrogen gas at 1.00 atm pressure and at 27°C.
4.9L
For a given amount of gas at a constant temperature, the volume of gas varies inversely with its pressure is a statement of ________ law.
Boyle's
If the temperature of a gas is lowered, the gas molecules will strike the walls of its container more frequently. (Assume that the container has a definite shape and volume.) Answer:
False
Water is a liquid at room temperature while methane is a gas. Which statement compares the intermolecular forces in these molecules correctly?
The intermolecular forces in water are stronger than those in methane.
Which of the following is NOT a postulate of the kinetic-molecular theory?
The molecules of a gas are strongly attracted to each other.
The density of He at STP is
0.179 g/L.
A gas is enclosed in a cylinder fitted with a piston. The volume of the gas is 2.00 L at 1.00 atm pressure. The piston is moved to increase the volume to 6.00 L. Which of the following is a reasonable value for the pressure of the gas at the greater volume?
0.333 atm
The density of O2 gas at STP is
1.43 g/l
The temperature at which a solid melts is the melting point of the solid. The melting point is an indication of the intermolecular forces that holds a solid together. Aluminum melts at 660°C. Gold melts at 1064°C. Lead melts at 328°C. Which one of the following ranks the intermolecular forces in these solid elements from the strongest to the weakest?
Au > Al > Pb
At a given temperature and pressure, the volume of a gas is directly proportional to the amount of gas present. This is a statement of
Avogadro's law
For which of the following is hydrogen bonding NOT a factor?
CH4
Which of the following compounds will have the highest melting point?
CaCL2, 6.2
The statement that the volume of a fixed amount of a gas at a constant pressure is directly proportional to its absolute temperature is known as ________ law.
Charles'
Assume that you have a sample of a gas. You know the volume, the temperature and the number of moles of the sample. Which of the following laws would you use if you wanted to calculate the pressure of the sample?
Ideal Gas Law
Why are the melting points of ionic compounds higher than the melting points of molecular compounds?
Ionic compounds have stronger forces holding them together than molecular compounds do. Thus, they require higher temperatures to overcome those forces.
