Unit 1 Section A HW Problems Pt. 2

#6:

a.  -mix all the ingredients together

    -put them in circles onto cookie sheets

    -bake them until they are hard

b. -chemical

   -physical

   -chemical

#7:

A substance has a uniform and definite composition as well as distinct properties (ex. oxygen and carbon dioxide).

#8:

a. Compound

b. Element

c. Compound

d. Element

e. Compound

f. Compound

g. Element

#9:

a. i, ii, iv, vi

b. iii, v

#10:

Provides which elements are used in the substance and how much of each element.

#11:

Chemical symbols represent each element present while chemical formulas represent which chemical compounds are present.

Concept Check

#1:

The copper is denser than the zinc.

#2:

Because the copper is dense than the zinc, the pennies of today have less copper and more zinc.

#3:

It doesn't make sense to have more of the denser material in the penny, because it is heavier than the zinc and people must carry it around.

A.7

#1:

a. Phosphorus

b. Nickel

c. Copper

d. Cobalt

e. Bromine

f. Potassium

g. Sodium

h. Iron

#2:

Phosphorus, nickel, cobalt, and bromine.

#3:

An element's symbol is more likely to be the same throughout the world because with different languages, the words of the elements change while the symbols stay the same.

#4:

a.  Hydrogen (2 atoms) and oxygen (2 atoms)

b. Calcium (1 atom) and chlorine (2 atoms)

c. Sodium (1 atom), hydrogen (1 atom), carbon (1 atom), oxygen (3 atoms)

d. Hydrogen (2 atoms), sulfur (1 atom), oxygen (4 atoms)

#5:

2H        +    O       =>   2H  O

    2                2                 2