Chapter 1- What Is Chemistry?

Question 1

What is chemistry?

Answer 1

The study of matter & the changes that matter undergoes

Question 2

Matter

Answer 2

Anything that has mass & occupies space.

Question 3

The scientific method

Answer 3

• Observations
• Hypothesis
• Experiments
• Theory

Question 4

Observations

Answer 4

Recording qualitative or qualitative data.

Question 5

Hypothesis

Answer 5

Explanation of observations.

Question 6

Experiments

Answer 6

Change one variable at a time. Test hypothesis.

Question 7

Theory

Answer 7

Explains experiment. Predicts further outcome.

Question 8

What is a measurement?

Answer 8

-Quantitative observation
-Number & unit
|-> ex.) 100 lbs
75 miles

Question 9

Scientific notation

Answer 9

A way of writing very large & small numbers.

Question 10

Scientific notation problem:

0.000167 = ?

Answer 10

1.67 • 10^-4

left positive, right negative

Question 11

Scientific notation problem (reverse):

4.33 • 10^2=?

Answer 11

433

for reverse, left negative, right positive

Question 12

Avogrado’s number

Answer 12

6.022 • 10^23

Question 13

Significant figures:

Nonzero integers?

Answer 13

Always count.

ex.) 465 (3 S.F.)

Question 14

Significant figures:

Leading zeroes?

Answer 14

Never count.

ex.) 0.00076 (2 S.F.)

Question 15

Significant figures:

Interior zeroes?

Answer 15

Always count.

ex.) 9.0056 (5 S.F.)

Question 16

Significant figures:

Trailing zeroes?

Answer 16

Significant if the number has a decimal point.

ex. ) 100 (1 S.F.)
100. (3 S.F.)
1. 00 • 10^2 (3 S.F.)
0. 000060 -> 6.0 •10^-5 (2 S.F.)

Question 17

Exact numbers

Answer 17

• not obtained by measuring devices
• determined by counting
• determined by definition
• have unlimited/infinite number of significant figures

Question 18

Multiplication & division with significant figures:

Answer 18

The smallest number of significant figures in the equation is the amount the answer should have.

ex.) 4.56 • 1.4= 6.384= 6.4

Question 19

Addition & subtraction with significant figures:

Answer 19

The number with the least amount of decimal places in the equation will be the same amount in the answer.

ex. ) 45.6 + 11.567 =
57. 167-> [57.2]

Question 20

Mass

Answer 20

{Amount of matter in a object}

• SI unit: kilogram (kg)
• commonly measure mass in grams(g) or milligrams(mg)
• 1kg= 2.2046 pounds
• 1lb= 453.59 grams

Question 21

Weight

Answer 21

Measures the force with which gravity pulls on an object

Question 22

Length

Answer 22

• SI unit= meter(m)
• 1m= 39.37 in.
• 1m= 100 cm
• 1cm= 10 mm
• 1in= 2.54 cm

Question 23

Temperature

Answer 23

{A measure of the average kinetic energy of the molecules in a sample}

• a higher temperature means a larger average kinetic energy

Question 24

Kelvin vs. Celsius

Answer 24

• The size of a “degree” on the Kelvin scale is the same as on the Celsius scale.

Question 25

Temperature conversion formulas:

Answer 25

K= C + 273

C= K-273

F= 1.8(C)+32

C= F-32 / 1.8