Chapter 1 - Chemistry: An Overview

Question 1

Theory (Model)

Answer 1

Set of tested hypotheses that gives an overall explanation of some natural phenomenon. Can change.

Question 2

Natural law

Answer 2

Summary of observed behavior

Question 3

Base units
 Mass
 Length
 Time
 Temperature
 Electric Current
 Amount of Substance
 Luminous Intensity

Answer 3

kilogram (kg)
meter (m)
time (s)
kelvin (K)
ampere (A)
mole (mol)
candela (cd)

Question 4

Prefixes
Mega
kilo
hecto
deka
deci
centi
milli
micro
nano

Answer 4

M (10^6)
k (10^3)
h (10^2)
da (10)
d (10^-1)
c (10^-2)
m (10^-3)
µ (10^-6)
n (10^-9)

Question 5

mass

Answer 5

measure of the resistance of an object to a change in its state of motion

Question 6

weight

Answer 6

force gravity exerts on an object

Question 7

accuracy

Answer 7

the agreement of a particular value with the true value

Question 8

precision

Answer 8

degree of agreement among several measurements of the same quantity

Question 9

random error

Answer 9

measurement has an equal probability of being high or low

Question 10

systematic error

Answer 10

occurs in the same direction each time (always high or low)

If systematic errors are absent, then high precision among several measurements is an indication of accuracy.

Question 11

Rules for Counting Sig. Figs.

Answer 11

1. nonzero integers are always significant.
2. Leading zeroes aren’t significant.
3. Zeroes between nonzero digits are significant
4. Trailing zeroes to the right end of the number are only significant if the number contains a decimal point.
   e. g) 100 = 1 sig fig
   e. g.) 1.00 = 3 sig figs
5. counting numbers have infinitely many sig figs (1 cow, 3 bells, etc.)

Question 12

Multiplying/Dividing

Answer 12

Number of sig figs in the result is the same as the number in the least precise measurement used in the calculation

Question 13

Adding/Subtracting

Answer 13

Result has same umber of decimal places as the least precise measurement used in the calculation

1.111-1.00 = .111 = .11

Question 14

Mixture

Answer 14

Combination of pure substances
Homogeneous (solution)- having visibly indistinguishable parts
Heterogeneous- visibly distinguishable parts

Question 15

Separating Mixtures

1-3. Physical change
4. Chemical change

Answer 15

1. distillation - heating a mixture to get one of its components to become a gas
2. filtration - separate liquid from solid
3. chromatography - parts of a mixture move through something at different rates
4. electrolysis - current passed through something to break it down into elements

Question 16

Separating Mixtures

Answer 16

distillation - heating a mixture to get one of its components to become a gas

filtration- separate liquid from solid