Matter/Chemical Change
Did a chemical change occur if the temperature changed during an experiment?
yes
Elements that are generally good conductors of heat and electricity are ___.
Metals
What is the best evidence that a chemical reaction occurred when two clear liquids were mixed and a cloudy solid formed? A: Color change B: Temperature remained the same C: Solid particles formed D: Volume increased
C: Solid particles formed.
Which best describes the force shown with an apple falling from a tree? A: Pulled toward the ground by gravity B: Fell due to wind friction C: Pulled by Earth's magnetic pull D: Pushed by applied forces
A: Pulled toward the ground by gravity.
The energy related to the motion of an object is called
B: Kinetic energy
Which container showed a chemical change: A (penny got wet) or B (bubbles formed)? Explain your choice.
Container B because bubbles formed in the liquid. (Gas production is evidence.)
Elements that are generally poor conductors of heat and electricity are ___.
Nonmetals
Multiple choice: Which of the following is evidence of a chemical change? A: Production of a gas B: Change in thermal energy C: Production of a precipitate D: Color change (choose all that apply)
All apply as evidence: A, B, C, D (production of gas, thermal energy change, precipitate, color change).
Which are examples demonstrating the force of friction? (A bike rolling down a hill; Rubbing hands together to keep warm; Air rushing over a car; A pot on a silicone pad)
Rubbing hands together to keep warm; Air rushing over a car is air resistance,a bike rolling down a hill has friction
What is the best way to represent potential energy and kinetic energy when a rock is falling off a cliff
C: As potential energy decreases, kinetic energy increases.
When cheese spoils and mold forms, is that a physical or chemical change? Explain why
Chemical change — mold growth is new substances forming
Elements that are average conductors of heat and electricity are ___.
Metalloids
Short answer: What does the formation of a precipitate mean in a lab?
Production of a solid when two solutions mix; a new solid forms and separates from solution.
What is Newton's Third law
for every action there is a equal and opposite reaction
Multiple choice: At what point would the roller coaster car have the greatest potential energy? (Use points labeled 3,4,5,6 )
At the top of the roller coaster.
True/False: Burning charcoal releases heat, indicating a chemical change has occurred.
True
The ability to be hammered into thin sheets is known as — A: Ductility B: Conductor C: Insulator D: Malleability
Malleability
True/False: If no color change occurs, then no chemical change has happened. Explain.
False — No color change does not guarantee no chemical change; other evidence may exist.
The net force on a box is 16N pushing to the left and 8 N to the right, and what direction will the box move? : Are they balanced?
No and to the left
Multiple choice: At what point would the roller coaster car have the greatest kinetic energy?
When it is coming to the bottom it will be going the fastest and have the most kinetic energy.
A piece of metal is heated and changes color but no gas forms. Is this definitely a chemical change?
Not necessarily; color change can be physical (oxidation often chemical).
Which type of element could the chemist be studying? shiny. malleable, good and a conductor of electricity
metal
Scenario: You mix two solutions; temperature rises, bubbles form, and the solution color changes. List at least three pieces of evidence here that indicate a chemical change and explain how each supports that conclusion.
Examples: Temperature change (exothermic/endothermic), gas bubbles (new gas formed), color change or precipitate (new substance). Each indicates new substances or energy change
According to Newton’s Third Law, what happens when a swimmer pushes against the pool wall?
The wall pushes back with the same force
Describe the energy transformations when a fan runs from a battery (or charged source).
Chemical energy → electrical energy (in battery-powered fans) → mechanical energy (fan blades spin). For an electric fan plugged into electrical grid: electrical → mechanical; if battery: chemical → electrical → mechanical.