Physical and Chemical Changes
An ice cube melting would be an example of a physical or chemical change? Why?
Physical, because an ice cube is made of water before and after melting.
What is the difference between speed and velocity?
Speed is how much distance is traveled over a given amount of time. Velocity tells us that AND the direction the object is traveling.
60 mph vs. 60 mph South
True or false: The solute is what you add to the solvent. We can increase the concentration of a solution by increasing the solvent.
FALSE! Yes, the solute is what we add to the solvent, but we must increase the concentration of the solution by increasing the amount of solute.
Is H2O an element or a compound?
Compound.
Roasting a marshmallow over a fire would be an example of a...
Chemical change
The bus driver slams on the breaks. Because of this, your body will move ___________ due to the Law of Inertia.
Ms. Donihoo makes lemonade with water, lemon juice, and sugar. What would be the solvent?
The water. The lemon juice and sugar would be the solutes since they are mixed into the water.
How many atoms of Carbon are in CO2?
1 atom of Carbon.
Adding a packet of Kool Aid to a cup of water would be an example of a physical or chemical change?
physical change
Speed is calculated by...
S = d/t
(distance divided by time)
A student puts 2 sugar cubes into a cup of water. How could they increase the concentration of sugar in their solution?
Add more sugar cubes, or decrease the amount of water.
Which of the following are compounds?
H2O, He2, C6H12O6, N2
H2O and C6H12O6.
He2 and N2 are elements because they only have one type of atom.
Ice cream melting would be an example of a ____________ change.
You run 3 miles in 0.5 hours (30 minutes). How fast were you running?
6 miles per hour.
The rate of dissolution is how fast solutes dissolve in a solvent. How can we increase the rate of dissolution?
Stirring, heating, or increasing the surface area of the solute.
How many Oxygen atoms are in CH3COOH?
2 Oxygen atoms
Name 3 ways we can tell a chemical change is occuring.
Change in smell, change in color, explosion, bubbles, rusting, rotting, precipitate produced, irreversible.
Speeding up - Upward curved slope
Slowing down - Downward curved slope
Returning to start - Negative slope
Which solution would be more concentrated: a gallon of water with 1 Kool-aid packet, or a gallon of water with 5 Kool-aid packets?
A gallon of water with 5 Kool-aid packets would be more concentrated.
How many elements are in the formula C6H12O6?
3 - Carbon, Hydrogen, and Oxygen.