Intro to Chemistry 105-2002

Question 1

The Scientific Method

Answer 1

Question 2

Measurement

Answer 2

Measurement always includes a number and a unit.

Examples:

120 lbs.

68 kg

Question 3

Standard Notation

Answer 3

Examples:

7.42

1,250

0.00541

Question 4

Scientific Notation

Answer 4

Examples:

1. 095 x 10⁵
2. 86 x 10^-5

* If the number has been turned into a small number, use a negative exponent. If the number has been turned into a large number, use a positive exponent. *

Question 5

Avogadro’s Number

Answer 5

6.022 x 10²³

The number of atoms or molecules you need to measure the size of a human being.

Question 6

What is the standard form for

1.42 x 10⁴ ?

Answer 6

14,200

* Move the decimal 4 places to the RIGHT

(because of the positive exponent in 10⁴) *

Question 7

**What is the scientific notation for **

0.00149 ?

Answer 7

1.49 x 10^-3

* The decimal must be moved 3 places to the right. When the decimal is being moved to the right, it is a negative exponent. When moved to the left, it becomes a positive exponent. *

Question 8

Conversion Chart

Answer 8

T Tera 10¹²

G Giga 10⁹

M Mega 10⁶

K Kilo 10³

h Hecto 10²

da Deka 10¹

————————————— BASE UNIT (g, m, L, sec, etc.)

d Deci 10^-1

c Centi 10^-2

m Milli 10^-3

µ Micro 10^-6

n Nano 10^-9

p Pico 10^-12

f Femto 10^-15

Question 9

Express 15,000,000,000m using metric prefixes.

Answer 9

15,000,000,000m =

15 x 10⁹m

• Take 10⁹
• In the conversion chart, 10⁹ is in giga (G)

15 x 10⁹m = 15 Gm

Question 10

Express 0.00000042g using

metric prefixes

Answer 10

0. 00000042g =
1. 2 x 10^-7

• Take 10^{<span>-7</span>}
• We see that we do not have 10^-7 in our conversion chart, so go down to 10^-6 instead, which is in Micro units (µ).

0.42 x 10^-6 = 0.42µg

Question 11

Unit Conversions

Answer 11

Mulitply the given unit by a conversion factor.

Question 12

Convert 9.5 cups into quarts

Answer 12

– GIVEN: 9.5 cups

– REQUESTING: Cups to quarts

– CONVERSION FACTOR: There are 4 cups in 1 quart

– ANSWER:2.38 qt

Question 13

Convert 4,250 cm to meters

Answer 13

– GIVEN: 4,250 cm

– REQUESTING: cm to meters

– CONVERSION FACTOR: There are 10^-2m in 1 cm

– ANSWER: 42.5 m

Question 14

How many cm are in 4.6 inches?

Answer 14

– GIVEN: 4.6 inches

– REQUESTING: How many cm in 4.6 inches

– CONVERSION FACTOR: There are 2.54 cm in 1 inch

– ANSWER:11.7 cm

Question 15

How many grams are in 160 lbs.

if 1 kg = 2.205 lbs. and a kilo = 10³g?

Answer 15

There are two different conversion here.

ANSWER: 72,562g

Question 16

Convert 235kg to lbs.

Answer 16

ANSWER: 518 lbs

Question 17

Convert 4585mL to qts. when

1.057 qt = 1L

Answer 17

ANSWER: 4.846 qts

Question 18

How many seconds are in 2.0 years?

Answer 18

ANSWER: 63,072,000 seconds in 2 years

Question 19

Convert 6.23 x 10⁶cm to km

Answer 19

ANSWER: 62.3 km