Question

1. as the gas in a rigid container is heated, its

a. pressure increases.
b. volume increases.
c. pressure decreases.
d. volume decreases.

1. a liquid with a low viscosity

a. has a definite shape.
b. flows quickly.
c. flows slowly.
d. fills its container.
◆ completion
fill in the line to complete each statement.

1. according to charless law, when the temperature of a gas increases in a flexible container, its ______________ increases.
2. gas particles that are not contained will always move from an area of ____________ pressure to an area of ____________ pressure.
3. ______________ energy comes from chemical bonds within matter.
4. ______________ occurs when the particles on the surface of a solid are directly released as a gas.
5. during every chemical and physical change, the total amount of energy stays the same. this principle is known as the ______________.

◆ true or false
if the statement is true, write true. if it is false, change the underlined word or words to make the statement true.

1. if a graph is a straight line that passes through point (0,0), two variables are considered directly proportional.
2. new substances are formed during physical changes.
3. during boiling, only particles on the surface of the liquid have enough energy to become gas.
4. the change from a solid to a liquid is sublimation.
5. gas pressure is found by dividing the force of its outward push by the area it pushes on.

Explanation:

• For question 9, in a rigid - container, volume is constant. According to Gay - Lussac's Law ($P/T = k$, where $P$ is pressure, $T$ is temperature and $k$ is a constant), as temperature increases, pressure increases.
• For question 10, viscosity is a measure of a fluid's resistance to flow. A low - viscosity liquid has low resistance to flow and thus flows quickly.
• For question 11, Charles's Law states that for a given mass of gas at constant pressure, $V/T=k$ (where $V$ is volume and $T$ is temperature), so when temperature increases in a flexible container, volume increases.
• For question 12, Gas particles move from high - pressure areas to low - pressure areas due to the pressure gradient.
• For question 13, Chemical energy comes from chemical bonds within matter.
• For question 14, Sublimation is the process where particles on the surface of a solid are directly released as a gas.
• For question 15, The principle that the total amount of energy stays the same during every chemical and physical change is known as the law of conservation of energy.
• For question 16, If a graph is a straight line passing through the origin (0, 0), the two variables are directly proportional.
• For question 17, No new substances are formed during physical changes; new substances are formed during chemical changes.
• For question 18, During boiling, all particles in the liquid have enough energy to become gas, not just surface particles (evaporation occurs on the surface).
• For question 19, The change from a solid to a liquid is called melting; sublimation is solid to gas.
• For question 20, Gas pressure is found by dividing the force of its outward push by the area it pushes on ($P = F/A$).

Answer:

1. a. pressure increases.
2. b. flows quickly.
3. volume
4. high; low
5. Chemical
6. Sublimation
7. law of conservation of energy
8. True
9. False (New substances are formed during chemical changes)
10. False (During boiling, all particles in the liquid have enough energy to become gas)
11. False (The change from a solid to a liquid is melting)
12. True