Key Concepts
When things get hotter, its _________ are moving ________ and have ________ kinetic energy.
When things get hotter, its molecules are moving faster and have more kinetic energy.
The energy that an object has because it's moving
Kinetic Energy
The moment when two objects hit each other.
Collision
A spoon at 20°C is placed into a mug of hot chocolate at 80°C. Explain what will happen to the kinetic energy of the molecules between the hot chocolate and the spoon.
The fast-moving hot chocolate molecules will collide with the spoon molecules, transferring energy until both reach a equilibrium.
A spoon at 20°C is placed into a mug of hot chocolate at 80°C. What is the equilibrium temperature?
50°C
The _______ of a system will transfer energy until the system reaches a stable state known as ______, in which all of the molecules are moving at about the same speed.
The molecules of a system will transfer energy until the system reaches a stable state known as equilibrium, in which all of the molecules are moving at about the same speed.
When something stays mostly the same over time.
Stability
When something becomes different over time.
Change
Sam is stacking two Lego bricks. The bottom Lego's molecules has faster moving molecules than the top Lego. What will happen to the kinetic energy once the Legos have been touching for a while?
The kinetic energy of the Legos will be at equilibrium.
Sam is stacking two Lego bricks. The bottom Smart Brick has a temperature of 10°C. The top brick has a temperature of 4°C. What is the equilibrium temperature? ?
7°C
__________ is a measure of the average kinetic energy of the molecules of a thing.
Temperature is a measure of the average kinetic energy of the molecules of a thing.
To move from one object or another or to one place to another.
Transfer
A group of atoms joined together in a particular way.
Molecule
A student was running late for school and had time to heat only 1 Eggo waffle. The heated waffle has a temperature of 38°C, while the other noncooked one is at 2°C. If the students wraps both of them in a paper towel, with the heated waffle on the bottom, which way is the kentic energy being transfer?
The kinetic energy is transferred to the bottom hot waffle to the top colder waffle.
A student was running late for school and had time to heat only 1 Eggo waffle. The heated waffle has a temperature of 38°C, while the other noncooked one is at 2°C. If the students wraps both of them in a paper towel and runs out the door, what will the equilibrium temperature be after a while?
20°C
________ is not created or destroyed. Therefore, as energy _________, it increases in one part of the system as it _______ in another part of the system.
Energy is not created or destroyed. Therefore, as energy transfers, it increases in one part of the system as it decreases in another part of the system.
A balanced state in which a system is stable, such as when two or more samples are the same temperature.
Equilibrium
A number that summarizes a set of data and that can be computed by adding all the numbers in a list and then dividing by the number of numbers in the list
Average
A student places a cold ice pack that is 0°C on their warm knee that is 37°C. In which direction is the kinetic energy transferring?
The kinetic energy is moving from the knee to the ice pack.
Two identical blocks of iron are touching. Block X is 150°C and Block Y is 50°C. After 20 minutes, they reach equilibrium. What is the equilibrium temperature of both blocks?
100°C
When two things are in contact, their molecules ________, and __________ transfers from the _____________ molecules to the __________ molecules.
When two things are in contact, their molecules collide, and kinetic energy transfers from the faster-moving molecules to the slower-moving molecules.
To reach a conclusion using evidence and reasoning.
Infer
A set of interacting parts forming a complex whole.
System
A large pot of water and a small cup of water are both 90°C. If you pour the cup into the pot, will the temperature increase, decrease, or stay the same? Why?
Stay the same because both samples have the same average kinetic energy.
Bolt A (Top) molecules are 10, 10, 10, 10.
Bolt B (Bottom) molecules are 30, 30, 30, 30.
What is the average temperature of each, and what is the final equilibrium?
A: 10 B: 30
Equilibrium: 20