Physical vs Chemical Changes
What kind of change is melting ice?
Physical change.
Why does weight change depending on location, but mass doesn't?
Weight is affected by gravity whereas mass is a measure of matter.
Heat flows from __________ to __________.
Hot to Cold
What is a chemical reaction?
A reaction that forms a new substance.
What is it called when we do another scientist's experiment?
Replication.
Burning wax is what kind of change?
Chemical, new substance is leftover.
Why is the Conservation of Mass considered a scientific law?
It describes repeatedly observed phenomenon without an explanation/reason why it happens.
What happens to a cold soda can in a warm room?
The heat from the warm room is transferred to the cold can until they reach the same temperature.
What does a decrease in temperature do to a chemical reaction?
It slows down the rate of the chemical reaction.
The variable you change in the beginning of an experiment is the________________________________.
Independent Variable.
William lost his phone in the ocean. One day, it washes up ashore and in his excitement he grabbed his phone and it fell on a rock. It shattered into many pieces and all of sudden it exploded leaving behind a strange odor and smoke. What kind of change is this?
A chemical change because gas was released and there's an odor left behind.
What happens to the mass of a glass jar after it breaks assuming we've collected all the pieces?
It stays the same.
What is the direction of heat flow from these three objects?
OB 1: 45 Celsius
OB 2: 15 Celsius
OB 3: 40 Celsius
OB 1 > OB 3 > OB 2
If Ares is mixing chemicals in a beaker but they are reacting slowly, what can Ares do to speed up the rate of the reaction?
Raise the temperature of the beaker.
What is called when you do multiple trials of your own experiment?
Repetition.
Burning wax is a chemical change.
The mass of salt and water is equal to 10g. What happens to the mass if we mix water with salt?
The mass stays the same.
What are the three types of heat transfer?
Conduction, Convection, Radiation.
What energy conversion can be evidence of a chemical reaction?
The releasing of light and heat.
What is a scientific theory?
Theories are frameworks that explain "how" or "why" natural phenomena occur.
The Sun undergoes a process called Nuclear Fusion. Hydrogen combines with other Hydrogen atoms to become Helium. This releases masses amounts of energy that we see/feel on Earth as heat & light. What kind of change is this?
Chemical Change.
When Lil' Timmay did a vinegar and baking soda experiment with a balloon and scale, he noticed that the mass of the solution changed from 5.8g to 4.9g. Why did the mass change?
What type of energy conversion is associated with friction?
Kinetic to light and heat (will accept sound as an answer and potential).
What are the 5 pieces of evidence that something may have undergone a chemical change?
1. Change of color
2. Change in odor/tase
3. Change in temperature
4. Formation of precipitation (forms a solid when liquids are combined)
5. Production of gas bubbles
What would cause scientists to change/revise their theories?
They can change when new evidence has been found (that either supports or refutes the theory).