6. the best way to understand the submicroscopic world is with ___
A. powerful microscopes
B. very accurate measuring devices
C. physical properties
D. models
7 an example of a chemical change is __
A. melting
b. electrical conductivity
c. burning
d. density
8 the structure of matter refers to its __
a. behavior
b. composition
c. measurements
d. reactions
9 water and hydrogen peroxide are both composed of atoms of hydrogen and oxygen, the differences lie in the __ arrangement of the atoms.
A. behavioral
B. composed
C. macroscopic
D. submicroscopic
10 when ice melts and becomes liquid water, it has undergone a __
A. chemical change
B. chemical propert
c. physical change
d. physical property
11 in ocean water, salt is a(n) __
a. alloy
b. solute
c. solution
d. solvent
12 how many atoms are present in one unit of sodium sulfate, Na2SO4?
A. 1
B. 2
C. 4
D. 7
15 the second row of the periodic table includes__ elements
a. 2
b. 8
c. 18
d. 32
2007-09-26 04:30:40 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry