Electrons
Energy levels are also called “shells” or ________.
orbitals
Chemicals to the left of the arrow in a chemical equation are the _______________, and the chemicals to the right of the arrow are the _____________.
reactants
products
What does the arrow mean in a chemical equation?
“yields” or “produces”
What is the Law of Conservation of Mass/Matter?
+ Random
Mass/matter is neither created nor destroyed
When balancing chemical equations, what are you allowed to change? What are you not allowed to change?
Coefficients
Subscripts
The outermost electrons of an atom are called:
+ Random
valence electrons
What are the reactants in:
4 Cr + 3 O2 → 2 Cr2O3
Cr and O2
Balance this chemical reaction:
__ SiO2 + __ H2F2 → __ SiF4 + __ H2O
1 SiO2 + 2 H2F2 → 1 SiF4 + 2 H2O
When can chemical bonds form?
When atoms transfer or share electrons
What is required to break a bond?
Energy
The outermost energy level of an atom can only hold ___ electrons.
8
Balance this chemical reaction:
__ CH4 + __ O2 → __ CO2 + __ H2O
1 CH4 + 2 O2 → 1 CO2 + 2 H2O
Balance this chemical reaction:
__ NH3 + __ H2SO4 → __ (NH4)2SO4
+ Random
2 NH3 + 1 H2SO4 → 1 (NH4)2SO4
How do the properties of products compare with the properties of its reactants?
Both physical and chemical properties change into different properties
During a chemical reaction, atoms are not ______________. They only _____________.
destroyed/created/lost/gained
rearrange
How many valence electrons does Astatine (At, Element #85) have?
7
Balance this chemical reaction:
__ Na3PO4 + __ KOH → __ NaOH + __ K3PO4
1 Na3PO4 + 3 KOH → 3 NaOH + 1 K3PO4
Balance this chemical reaction:
__ PCl5 + __ H2O → __ H3PO4 + __ HCl
1 PCl5 + 4 H2O → 1 H3PO4 + 5 HCl
What is the difference between exothermic and endothermic reactions?
Exothermic reactions release heat and feel hot
Endothermic reactions absorb heat and feel cold
How many atoms are involved in this reaction?
Fe3O4 + 4 H2 → 3 Fe + 4 H2O
+ Random
15 atoms
What is the most amount of electrons that can fill up the 3rd energy level of an atom?
18 electrons
Balance this chemical reaction:
__ C3H8 + __ O2 → __ H2O + __ CO2
+ Random
1 C3H8 + 5 O2 → 4 H2O + 3 CO2
Balance this chemical reaction:
__ C2H3Br + __ O2 → __ CO2 + __ H2O + __ Br2
4 C2H3Br + 11 O2 → 8 CO2 + 6 H2O + 2 Br2
Just so you know, this level of difficulty won’t be on the test.
What happens to chemical bonds and atoms during a chemical reaction?
Original bonds break, atoms rearrange, and new bonds form
How many oxygen atoms are involved in this reaction?
2 C6H6O2 + 13 O2 → 12 CO2 + 6 H2O
30 atoms