15 Questions
What happens when a substance is heated?
The atoms/molecules gain energy and move faster
Which of the following best describes temperature?
A measurement of the average speed of atoms/molecules
When a substance is cooled, what happens to the atoms/molecules?
They lose energy and move slower
What happens to the volume of a substance when it is heated?
The volume increases
Which of the following statements is true about atoms/molecules when a substance is cooled?
They move closer together and the volume decreases
What is the primary reason for the increase in volume when a substance is heated?
The atoms/molecules move faster and spread further apart
Which of the following best describes the behavior of gaseous atoms/molecules?
They travel in straight lines until they collide
What is the primary reason for the decrease in volume when a substance is cooled?
The atoms/molecules move slower and get closer together
How does the ability to detect odors relate to the behavior of gaseous particles?
Odor particles travel randomly and can reach our noses
What does the model illustrate about the particles in the bigger balloon?
They are moving faster due to a gain in energy
What happens to the temperature and volume of the balloon when the particles are moving slower?
The temperature increases and the volume decreases
What is the difference between evaporation and boiling, according to the text?
Evaporation occurs at the surface, while boiling occurs throughout the liquid.
What does the text say about the relationship between temperature and the rate of evaporation?
Evaporation occurs faster at higher temperatures.
What happens when a gas comes in contact with a cool surface?
The gas molecules slow down and become a liquid.
What happens to the temperature of a substance when it is boiling, according to the text?
The temperature remains constant until all the molecules turn into a gas.
Study Notes
Energy Transfer and Temperature
- Energy transfer to a substance results in a gain of energy, causing the atoms/molecules to move faster and the temperature to increase.
- Energy transfer from a substance results in a loss of energy, causing the atoms/molecules to move slower and the temperature to decrease.
- Temperature is a measurement of the average speed of atoms/molecules.
Particle Movement and Volume
- When particles move faster, the collisions are stronger and more frequent, causing the atoms/molecules to spread further apart and the volume of the substance to increase.
- When particles move slower, the collisions are weaker and less frequent, causing the atoms/molecules to get closer together and the volume of the substance to decrease.
- The atoms/molecules themselves do not expand or shrink.
Gas Properties
- Gaseous atoms/molecules travel in straight lines until they collide with each other or an object, causing their direction to change.
- Gaseous particles travel in all directions, allowing them to reach our noses and be detected if they have an odor.
Phase Changes
- Evaporation occurs when molecules at the surface of a liquid gain enough energy to enter the gaseous state.
- Evaporation can occur at any temperature, but the warmer something is, the faster evaporation occurs.
- Boiling occurs when molecules throughout the liquid gain enough energy to enter the gaseous state.
- The boiling point of a substance is the temperature at which molecules throughout the liquid can change to the gaseous state.
- Condensation occurs when molecules in the gaseous state slow down and become a liquid, often happening when the gas comes in contact with a cool surface.
Test your knowledge on the concepts of heating and cooling substances, energy transfer, temperature, and atom/molecule speed. Learn about how energy transfer affects the speed of particles and results in temperature changes.
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