110 module1 2

Scientific Notation 1,000,000 = 1 million

Scientific Notation 1,ooo,ooo = 1 million = 1 x 106

Move the decimal point to a value between 1 and 10

1 000 000. ------> 1 x 106

Move the

Decimal 6 places to the

left

Scientific Notation

There are 0.0000001 H+ ions in a neutral solution

Scientific Notation

There are 0.0000001 H+ ions in a neutral solution

= 1 x 10-7 H+ ions

Scientific Notation Format:

450,000 = 4.5 x 105

0.000073 = 7.3 x 10-5

Number between 1 and 9.99

Power of Ten10 x 10 x 10 x . . .x

Scientific Notation

NaCl crystal

Distance Na+ .. Cl–

0.000000000278 m

Scientific Notation

NaCl crystal

Distance Na+ .. Cl–

0.000000000278 m

= 2.78 x 10-10 m

Scientific Notation

US National Debt (2016)

$18, 200,000,000,000

Scientific Notation

US National Debt (2016)

$18, 200,000,000,000

= $1.82 x 1013

Scientific Notation

Scientific calculators

8.978+01 = 8.978 x 101

= 89.78

5.0627 E+15= 5.0627 x 1015

= 5,062,700,000,000,000

Significant Figures

How do you know how many decimal places to use?

All of the digits known with certainty plus one estimated digit.

Significant Figures

Rules

Any non-zero digit is Significant

Any zero between non-zero digits is Significant

All zeros to the left of the first non-zero digit are NOT Significant

Zeros after the decimal point are Significant

Zeros that occur without a decimal point are NOT significant

Significant Figures

How many significant figures does each value have?

Value # Significant figures

0.00008 m

36,000 km

22.00 g

5.05 x 10-3 mg

Significant Figures

How many significant figures does each value have?

Value # Significant figures

0.00008 m 1

36,000 km 2

22.00 g 4

5.05 x 10-3 mg 3

Significant Figures

When multiplying or dividing, the result cannot have more sig figs than either of the original values

In addition or subtraction, the answer cannot have digits after the decimal than the original values

Rounding: If the first digit to be dropped is 4 or less, the last digit and any following are dropped. If the last digit is 5 or more, the last digit is kept and increased by 1.

Significant Figures

A 2002 Toyota Camry uses 11.70 gallons of gas to travel 278 miles – what is its mileage?

Significant Figures

A 2002 Toyota Camry uses 11.70 gallons of gas to travel 278 miles – what is its mileage?

3 sig figs

278 miles = 23.8 mi/gal

11.7o gallons 3 sig figs

4 sig figs

Significant Figures

A 2002 Toyota Camry uses 11.70 gallons of gas to travel 278 miles – what is its mileage?

3 sig figs

278 miles = 23.8 mi/gal

11.7o gallons 3 sig figs

4 sig figs

The answer CANNOT have more significant figures than the input value with LESS sig figs.

Significant Figures

Significant Figures

Blood cholesterol level = 185 mg/dL

= ?? g/L

How many g of

cholesterol are in 5 Liters

Of blood?

Significant Figures

Blood cholesterol level = 185 mg/dL x g/1000mg x 10dL/L

= 1.85 g/L

How many g of

cholesterol are in 5L blood?

1.85 g/L x 5 L

= 9.25 g = 9 g

The answer is limited to 1 sig fig

Density Archimedes

confirmed that a crown was

made of gold rather than

gold-covered metal by measuring

its density by water displacement

mass

Density =

volume

Density

A piece of lead measures 0.5 cm x 1.55 cm x 25 cm and has a mass of 220.9 grams – what is its density?

Density A piece of lead measures 0.50 cm x 1.55 cm x 25 cm

and has a mass of 220.9 grams – what is its density?

mass

Density = volume

220.9 g

= 19.38 cm3

= 11.40 g/cm3 = 11 g/cm3 [2 sig figs]

Bone Density

Decreases with age (Osteoporosis)

Normal weakened

mgcm3

Body Mass Index (BMI)

Density & Temperature

Density measurement must include temperature

phase changes

Temperature

Temperature is a measure of the amount of Kinetic Energy in a substance

Kinetic Energy = Energy of motion

http://phet.colorado.edu/en/simulation/states-of-matter

Temperature Scales

°C = (°F – 32) x 0.55

°F = (°C x 1.8) + 32

K = °C +273

Temperature Scales°F °C K

57°F

-75°C

6

106°F

°C = (°F – 32) x 0.55

°F = (°C x 1.8) + 32°

K = °C +273

Temperature Scales°F °C K

57°F 14°C 287 K

-103°F -75°C 198 K

-449°F -267°C 6

106°F 41°C 314 K

°C = (°F – 32°) x 0.55

°F = (°C x 1.8) + 32°

K = °C +273°

States of Matter

melting

Freezing

evaporating

condensing

Phase Changes

Boiling Point

For water Tb = 100°C = 373 K

Freezing Point

For water, Tf = 0°C = 273K

Heating & Cooling Curves

Heat of Fusion

Energy necessary to separate particles

For water: 80 cal/g

Heat of Fusion

Ice cube tray hold 325 g water. If the water is originally at 25°C how many calories must be removed to cool and freeze the water at 0°C?

Heat of Fusion Ice cube tray hold 325 g water. If the water is originally at 25°C

how many calories must be removed to cool and freeze the water at 0°C?

Cooling:

325 g x 1 cal/g°C x 25°C = 8125 cal

• Freezing:

325 g x 80cal/g = 26000 cal

TOTAL: 34125 cal = 34.125 kilocalories

Heat of Vaporization

Energy to vaporize 1 g of liquid to gas

Water: 540 cal/g

Steam vs. Hot Water

Why does steam burn more than hot water at the same temperature? (100°C) body temp = 37°C

Hot water:

25 g x 63°C x 1 cal/g°C = 1575 cal

Steam:

25 g x 540 cal/g = 13500 cal

TOTAL: 15075 cal (10x that of hot water)