Which of the following is NOT a sign of a chemical change:
1. Drastic, unpredictable color change
2. Fizzing
3. Turning cloudy and mixing
4. Light and sound being produced
#3 Turning cloudy and mixing together IS NOT a sign of a chemical change occurring.
100
What happens during a chemical change?
A. New matter and mass is created
B. New atoms are formed
C. Bonds break and reform to make a new substance
D. No new substance is formed
C. Bonds break and form to create a NEW SUBSTANCE!
100
What phase change occurs during evaporation (what state to what state)?
Liquid to gas
100
What are the reactants in this chemical equation:
CH4 + O2 = CO2 + H2O
CH4 and O2
200
What are 2 types of conductivity?
Thermal (heat) conductivity and electrical conductivity
200
Water condensing on the windshield is what type of change?
Physical Change
200
A. What is it called when a solid goes to gas?
B. What is it called when gas goes to liquid?
A. Sublimation
B. Consdensation
200
Name 4 ways to speed up a reaction.
Increase temperature (heat)
Stir it
Increase surface area (crushing it into powder)
Increase pressure
Increase concentration
300
What is one way to increase the surface area of a reactant?
Crush it up into smaller pieces
300
What are the reactants in the chemical change CELLULAR RESPIRATION?
Sugar (C6H12O6) and oxygen (O2)
300
What is the slope of the temperature during melting/freezing?
0. Stays the same. TEMP DOES NOT CHANGE DURING A PHASE CHANGE!
300
If I start with 4 atoms of Carbon in the reactants and combine it with oxygen to make molecules of carbon dioxide, how many atoms of Carbon will be in the products?
4 atoms of Carbon (The SAME number of atoms on the REACTANTS and PRODUCTS side. The Law of Conservation of Mass)
400
The mass of the reactants was 8.2 grams and the mass of the products was 7.5, what was the mass of the gas that was produced but not captured by the students?
0.7 grams
400
What are 4 significant OXYGEN reactions in nature?
In death valley, which is below sea level, do noodles take more or less time to cook?
Noodles take LESS time to cook because the water will be hotter in a liquid phase.
400
Which of the following happens during a chemical change?
A. Atoms rearrange and bonds are broken and formed.
B. New atoms are created
C. Matter appears and disappears.
D. Matter is created or destroyed.
A is the only correct answer. New ATOMS are not formed, only rearranged to form new molecules.