A) What of the following is an advantage of the thermal properties of plastic? (1 point)

Question

The thermal conductivity of plastic is very high, making it a good material to transmit heat.
Plastics are easy to mold into any shape.
Plastics are safe to use in microwave ovens.
Heating plastics eliminates the risk of BPA exposure.
A) Which phase change is the opposite of boiling? (1 point)
freezing
condensation
melting
evaporation
A) As the pressure of a gas decreases to half its original value, what happens to the volume of
the gas if temperature is held constant? (1 point)
The volume increases to twice its original value.
The volume increases to four times its original value.
The volume decreases to half of its original value.
The volume decreases to one-fourth of its original value.

Answer 1

A) The correct answer regarding the advantages of the thermal properties of plastic is:
Plastics are safe to use in microwave ovens.

A) The phase change that is the opposite of boiling is:
condensation.

A) According to Boyle's Law, when the pressure of a gas decreases to half its original value while the temperature is held constant, the volume of the gas will:
The volume increases to twice its original value.

Answer 2

A) There are 300 light particles in an airtight container. Which adjustment would increase
the speed of the particles? (1 point)
keeping the volume constant and replacing the light particles with heavy particles
keeping the pressure constant and increasing the temperature
keeping the temperature constant and increasing the container volume
keeping the volume constant and cooling the container
A) The relationships among which variable quantities are expressed by the ideal gas law
equation? (1 point)
pressure, volume, temperature, number of moles
volume, temperature, number of moles, gas constant
pressure, volume, number of moles, mass
pressure, volume, temperature, molar mass
A) When salt dissolves completely in water, which term best describes the role of water in the
salt-water mixture? (1 point)
solute
molarity
concentration
solvent
A) Which statement best describes what happens when oil and water are stirred together?
(1 point)
Oil and water molecules have like charges, causing them to repel each other and separate.
Water are positively charged and oil molecules are negatively charged, causing them to repel
each other and separate.
Oil molecules repel each other, leading to complete mixing of the two substances.
Water molecules attract each other, but they will not attract oil molecules, causing separation.

Answer 3

A) The adjustment that would increase the speed of the particles in the airtight container is:
keeping the pressure constant and increasing the temperature.

A) The relationships among the variable quantities expressed by the ideal gas law equation are:
pressure, volume, temperature, number of moles.

A) When salt dissolves completely in water, the term that best describes the role of water in the salt-water mixture is:
solvent.

A) The statement that best describes what happens when oil and water are stirred together is:
Oil and water molecules have like charges, causing them to repel each other and separate.

Answer 4

A) Crystals are made using supersaturated solutions of solids in water. These solutions hold
more of the solute than they would at room temperature. How are these solutions made?
(1 point)
The water would need to be chilled to a lower temperature, which would give molecules and ions
more kinetic energy, increasing solubility.
The water would need to be heated to a higher temperature, which would give molecules and
ions more kinetic energy, increasing solubility.
The water would need to be heated to a higher temperature, which would take kinetic energy
away from molecules and ions, increasing solubility.
The water would need to be chilled to a lower temperature, which would take kinetic energy away
from molecules and ions, increasing solubility.
A) Which of these substances would be more soluble in cold water than warm water? (1 point)
sugar powder
sodium chloride crystals
potassium chloride salt
oxygen gas

Answer 5

A) Supersaturated solutions of solids in water are made by:
The water would need to be heated to a higher temperature, which would give molecules and ions more kinetic energy, increasing solubility.

A) The substance that would be more soluble in cold water than warm water is:
oxygen gas.

Answer 6

A) How is a mole related to concentration? (1 point)
The number of particles of solute in a solution is measured in moles.
The mass of the solute in a solution is measured in moles.
The volume of particles of solute in a solution is measured in moles.
The saturation point of a solution is measured in moles.
A) Which statement best describes what it means when something is classified as a strong
acid? (1 point)
It is present in low quantities in a solution.
It is present in large quantities in a solution.
It easily dissociates into ions in solution.
It resists dissociating into ions in solution.

Answer 7

A) A mole is related to concentration in that:
The number of particles of solute in a solution is measured in moles.

A) The statement that best describes what it means when something is classified as a strong acid is:
It easily dissociates into ions in solution.

Answer 8

Based on patterns in the periodic table, which list shows the acids in order from strongest to
weakest?
(1 point)
HCl, H2S, PH3
HCl, PH3
, H2S
H S, PH , HCl 2 3
PH , H S, HCl

Answer 9

Based on patterns in the periodic table, the correct order showing the acids from strongest to weakest is:
HCl, H2S, PH3.

Hydrochloric acid (HCl) is a strong acid, while hydrogen sulfide (H2S) and phosphine (PH3) are much weaker acids, with H2S being stronger than PH3.

Answer 10

A) What is the pH of a 1 × 10 mol HCl solution? (1 point)
−4
6
4
2
8

Answer 11

To find the pH of a \(1 \times 10^{-4}\) mol HCl solution, you can use the formula for pH:

\[ \text{pH} = -\log[\text{H}^+] \]

Since HCl is a strong acid, it fully dissociates in solution, so the concentration of \( \text{H}^+ \) ions is equal to the concentration of the HCl solution.

For a \(1 \times 10^{-4}\) mol HCl solution:

\[ \text{pH} = -\log(1 \times 10^{-4}) = 4 \]

Thus, the pH of the solution is 4.