Name: ______Date:
Period:
REVIEW: Chemical Changes, Reactions and Equations
Fill in the Blank and Short Answer
1.)A chemical ______is a result of a chemical reaction.
2.)The ______are materials that are present at the beginning of a reaction written on the ______side of the yield arrow.
3.)The ______are materials formed in a ______reactionand are written on the ______side of the equation arrow.
4.)What are the numbers in front of the formulas, indicating the number of molecules involved in the reaction? ______
5.)Numbers that appear ______and to the right of a chemical symbol, indicating the specific number of atoms of each element found in the substance are called ______.
6.)What is the simplest form of pure substance and can be broken down into atoms?
7.)What is a chemical substance that is composed of at least two different types of elements chemically combined?
8.)What is the simplest part of a compound made of two or more atoms chemically combined to form one unit?
Evidences of a Chemical Reaction:
Write and describe the evidence of a chemical reaction for each word.
9.)Please-
10.)Excuse-
11.)Burps-
12.)Coughs-
13.)Sneezes-
Put a P next to the Physical Changes and a C next to the Chemical Changes.
___ Aluminum foil is cut in half.
___ Milk goes sour.
___ Clay is molded into a new shape.
___ Jewelry tarnishes.
___ Butter melts on warm toast.
___ Bread becomes toast.
___ Water evaporates from the surface of the ocean.
___ Rust forms on a nail left outside.
___ A juice box in the freezer freezes.
___ Gasoline is ignited.
___ Rubbing alcohol evaporates on your hand.
___ Hydrogen peroxide bubbles in a cut.
___ Food scraps are turned into compost in a compost pile.
___ A match is lit.
___ You take an antacid to settle your stomach.
___ Your body digests food.
Find how many atoms of each element are in the Chemical Formulas below. Then calculate the TOTAL number of atoms for each formula. Show your WORK!
Example:Ag2Cl2
Ag= 2 atoms Total= 4 atoms
Cl= 2 atoms
Ag2Cl2 Mg(ClO3)2
Al(NO2)3 3MnPb8(Si2O7)3
4Ca(H2PO2)2 2HClO3
Cu(OH)2CO3Fe2O3
Label the parts of a Chemical Equation.
1.) Circle the Products
2.) Put a square around the Reactants
3.) Put a triangle around the Coefficients
4.) Underline the Subscripts
5.) Trace the Yield symbol
Sunlight Energy
2H2O + CO2 ------> 2H2O + O2 + C6H12O6
- Is the ABOVE equation Balanced or Unbalanced? ______
Balance it:Below is the equation for cellular respiration. It is unbalanced and you must balance it. (Use the rules and procedures learned in class.) Show your WORK!
C₆H₁₂O₆ + O₂ → CO₂ + H₂O + [energy]
Directions:Balance the following chemical equations. Please rewrite the equation for your answer.
CaCl2 + Na2SO4 → CaSO4 + NaCl
Na + O2 → Na2O
Zn + HCl→ ZnCl2 + H2
N2 + H2 → NH3
Al2O3 → Al + O2
C2H6 + O2 → CO2 + H2O
1