1. Colegio San Patricio
Chemistry 9th grade
Name______________________________________________ Date _________________
1.- The following are chemical changes except:
a) burning coal b) cutting a piece of bread
c) explosion of fireworks d) digestion of food
2.- Which of the following is NOT a clue that a chemical reaction is taking place?
a) a substance dissolves b) a change in color
c) a precipitate forms d) bubbles form
3.- The new substances produced in a chemical reaction have:
a) the same properties as the original substances
b) different physical properties from the original
c) different chemical properties from the original
d) different physical and chemical properties from the original
4.- A chemical reaction is:
a) the rearrangement of atoms
b) the breaking of bonds and the formation of new bonds
c) process that changes the identify of a substance
d) all are correct
Answer the following questions
5.- What evidence shows that the following are chemical reactions?
7.-
a) a yellow liquid is mixed with a colorless liquid and a yellow precipitate is formed at
the bottom of the container
b) a red solid is placed in sunlight and after a period of time in becomes an opaque,
orange solid
c) a silver metal when lit, reacts with oxygen in the air and produces light and heat.
Classify the following chemical reactions
NaHCO3  Na2CO3 + H2O + CO2 _______________________________
C8H18 + O2  CO2 + H2O _______________________________
AgNO3 + CaCl2  AgCl + Ca(NO3)2 __________________________________________________
Mg + HCl  MgCl2 + H2 __________________________________________________
NO + O2  NO2 _________________________________________________