Classification Of Matter (Page 4 of 4) in pdf

Classification Of Matter Page 4

Law of Deﬁnite Proportions

• The mass of the compound is equal to the sum of the masses of the elements

that make up the compound.

• The ratio of the mass of each element to the total mass of the compound is a

percentage called the _______________________________________ .

• Equation (ﬁll in):

percent by mass (%) =

x 100

Review Questions

Identify each of the following as an example of a homogeneous mixture or

heterogeneous mixture.

A. a pile of rusty iron ﬁlings _______________________

B. 70% isopropyl rubbing alcohol _______________________

C. Saltwater _______________________

D. Gasoline _______________________

Identify each of the following as an example of an element or a compound.!

A. sucrose (table sugar) _______________________

B. the helium in a balloon (He) _______________________

C. baking soda (sodium bicarbonate, NaHCO

) _______________________

D. a diamond (carbon, C) _______________________

A 134.50-g sample of aspirin is made up of 6.03 g of hydrogen, 80.70 g of

carbon, and 47.77 g of oxygen. What is the percent by mass of each element in

aspirin?

A 2.89-g sample of sulfur reacts with 5.72 g of copper to form a black

compound. What is the percentage composition of the compound?

Calculate the % mass of each element in C

(Atomic mass of C = 12, H=1,

O=16)

Classification Of Matter Page 4