Temperature and Density

Temperature and Temperature and DensityDensity

Chapter 2.9/3.10Chapter 2.9/3.10

Temperature ScalesTemperature Scales FahrenheitFahrenheit CelsiusCelsius KelvinKelvin

Anders Celsius1701-1744

Lord Kelvin(William Thomson)1824-1907

Temperature ScalesTemperature Scales

Boiling point Boiling point of waterof water

Freezing point Freezing point of waterof water

CelsiusCelsius

100 ˚C100 ˚C

0 ˚C0 ˚C

KelvinKelvin

373 K373 K

273 K273 K

FahrenheitFahrenheit

32 ˚F32 ˚F

212 ˚F212 ˚F

Calculations Calculations Using Using TemperatureTemperature

Generally require temp’s in kelvinsGenerally require temp’s in kelvins

T (K) = t (˚C) + 273.15T (K) = t (˚C) + 273.15

t (˚C) = T (K) - 273.15t (˚C) = T (K) - 273.15

Body temp = 37 ˚C + 273 = 310 KBody temp = 37 ˚C + 273 = 310 K

Liquid nitrogen = -196 ˚C + 273 = 77 KLiquid nitrogen = -196 ˚C + 273 = 77 K

Generally require temp’s in kelvinsGenerally require temp’s in kelvins

T (K) = t (˚C) + 273.15T (K) = t (˚C) + 273.15

t (˚C) = T (K) - 273.15t (˚C) = T (K) - 273.15

Body temp = 37 ˚C + 273 = 310 KBody temp = 37 ˚C + 273 = 310 K

Liquid nitrogen = -196 ˚C + 273 = 77 KLiquid nitrogen = -196 ˚C + 273 = 77 K

Fahrenheit Formula Fahrenheit Formula

Zero point: 0°C = 32°FZero point: 0°C = 32°F

°F = 9/5 °C + 32°F = 9/5 °C + 32

Celsius Formula Celsius Formula

°C = °C = ( (°F – 32) * 5/9°F – 32) * 5/9

Temperature ConversionsTemperature Conversions

A person with hypothermia has a body A person with hypothermia has a body temperature of 29.1°C. What is the body temperature of 29.1°C. What is the body temperature in °F? temperature in °F?

°F °F = = 9/5 (29.1°C) + 329/5 (29.1°C) + 32

= = 52.4 + 3252.4 + 32

= = 84.4°F84.4°F

Learning Check Learning Check

The normal temperature of a The normal temperature of a chickadee is 105.8°F. What is that chickadee is 105.8°F. What is that temperature in °C?temperature in °C?

1) 73.8 °C 1) 73.8 °C

2) 58.80 °C2) 58.80 °C

3) 41.00 °C3) 41.00 °C

4) 41.0 °C4) 41.0 °C

Learning Check Learning Check

Pizza is baked at 455°F. What is Pizza is baked at 455°F. What is that in °C?that in °C?

1) 437 °C1) 437 °C

2) 235°C2) 235°C

3) 221°C3) 221°C

DENSITYDENSITY - an - an important and useful important and useful physical propertyphysical property

Density mass (g)volume (cm3)


Mercury

13.6 g/cm13.6 g/cm33 21.5 g/cm21.5 g/cm33

Aluminum

2.7 g/cm2.7 g/cm33

Platinum

DENSITYDENSITY Intensive Property: depends only on Intensive Property: depends only on

the composition of substance not the composition of substance not size.size.

Density generally decreases as Density generally decreases as temperature increasestemperature increases

Units = g/cmUnits = g/cm33 or g/mL or g/mL

ProblemProblem A piece of copper has a A piece of copper has a mass of 57.54 g. It is 9.36 cm mass of 57.54 g. It is 9.36 cm long, 7.23 cm wide, and 0.95 mm long, 7.23 cm wide, and 0.95 mm thick. Calculate density (g/cmthick. Calculate density (g/cm33).).



StrategyStrategy1. Get dimensions in common 1. Get dimensions in common

units.units.

2.2. Calculate volume in cubic Calculate volume in cubic centimeters.centimeters.

3. Calculate the density.3. Calculate the density.

SOLUTIONSOLUTION

1. Get dimensions in common units.1. Get dimensions in common units.

2.2. Calculate volume in cubic Calculate volume in cubic centimeters.centimeters.

3. 3. Calculate the density.Calculate the density.

0.95 mm • 1cm

10 mm = 0.095 cm

57.54 g

6.4 cm3 = 9.0 g / cm3

(9.36 cm)(7.23 cm)(0.095 cm) = 6.4 cm(9.36 cm)(7.23 cm)(0.095 cm) = 6.4 cm33

Note only 2 significant figures in the answer!Note only 2 significant figures in the answer!

PROBLEM: Mercury (Hg) has a PROBLEM: Mercury (Hg) has a density of 13.6 g/cmdensity of 13.6 g/cm33. What is . What is the mass of 95 mL of Hg in the mass of 95 mL of Hg in grams? In pounds?grams? In pounds?

PROBLEM: Mercury (Hg) has a PROBLEM: Mercury (Hg) has a density of 13.6 g/cmdensity of 13.6 g/cm33. What is . What is the mass of 95 mL of Hg in the mass of 95 mL of Hg in grams? In pounds?grams? In pounds?

StrategyStrategy

1.1.Use density to calc. mass (g) from volume.Use density to calc. mass (g) from volume.

2.2.Convert mass (g) to mass (lb)Convert mass (g) to mass (lb)

Need to know conversion factorNeed to know conversion factor

= 454 g / 1 lb= 454 g / 1 lb

PROBLEM: Mercury (Hg) has a PROBLEM: Mercury (Hg) has a density of 13.6 g/cmdensity of 13.6 g/cm33. What is the . What is the mass of 95 mL of Hg?mass of 95 mL of Hg?


First, note thatFirst, note that 1 cm1 cm33 = 1 mL = 1 mL

1.1. Convert volume to Convert volume to massmass



95 cm3 • 13.6 g

cm3 = 1.3 x 103 g

1.3 x 103 g • 1 lb

454 g = 2.8 lb

2.2. Convert mass (g) to mass (lb)Convert mass (g) to mass (lb)

Learning CheckLearning Check

Osmium is a very dense metal. What is its Osmium is a very dense metal. What is its

density in g/cmdensity in g/cm3 3 if 50.00 g of the metal if 50.00 g of the metal occupiesoccupies

a volume of 2.22cma volume of 2.22cm33??

1) 2.25 g/cm1) 2.25 g/cm33

2)2) 22.5 g/cm22.5 g/cm33

3)3) 111 g/cm111 g/cm33

SolutionSolution

2) Placing the mass and volume of the 2) Placing the mass and volume of the osmium metal into the density setup, we osmium metal into the density setup, we obtainobtain

D = D = massmass = = 50.00 g 50.00 g = = volumevolume 2.22 cm2.22 cm33

= 22.522522 g/cm= 22.522522 g/cm3 3 == 22.5 g/cm22.5 g/cm33

Volume DisplacementVolume Displacement

A solid displaces a matching A solid displaces a matching volume of water when the solid is volume of water when the solid is placed in water.placed in water.

33 mL33 mL25 mL 25 mL


What is the density (g/cmWhat is the density (g/cm33) of 48 g of a ) of 48 g of a metal if the metal raises the level of water metal if the metal raises the level of water in a graduated cylinder from 25 mL to 33 in a graduated cylinder from 25 mL to 33 mL? mL?

1) 0.2 g/ cm1) 0.2 g/ cm33 2) 6.0 g/m 2) 6.0 g/m3 3 3) 252 g/cm3) 252 g/cm33

33 mL33 mL

25 mL25 mL

The Density of WaterThe Density of Water

The density of water is 1 g/mLThe density of water is 1 g/mL Anything that sinks in water has a Anything that sinks in water has a

higher density and anything that higher density and anything that floats has a lower densityfloats has a lower density


Which diagram represents the liquid Which diagram represents the liquid layers in the cylinder?layers in the cylinder?

(K) Karo syrup (1.4 g/mL), (V) vegetable (K) Karo syrup (1.4 g/mL), (V) vegetable oil (0.91 g/mL,) (W) water (1.0 g/mL)oil (0.91 g/mL,) (W) water (1.0 g/mL)

1)1) 2) 2) 3) 3)

K

K

W

W

W

V

V

VK


The density of octane, a component The density of octane, a component of gasoline, is 0.702 g/mL. What is of gasoline, is 0.702 g/mL. What is the mass, in kg, of 875 mL of octane?the mass, in kg, of 875 mL of octane?

1) 0.614 kg1) 0.614 kg

2) 614 kg2) 614 kg

3) 1.25 kg3) 1.25 kg


If blood has a density of 1.05 g/mL, If blood has a density of 1.05 g/mL, how many liters of blood are donated how many liters of blood are donated if 575 g of blood are given?if 575 g of blood are given?

1) 1) 0.548 L0.548 L

2) 2) 1.25 L1.25 L

3) 3) 1.83 L1.83 L


A group of students collected 125 empty A group of students collected 125 empty aluminum cans to take to the recycling aluminum cans to take to the recycling center. If 21 cans make 1.0 pound of center. If 21 cans make 1.0 pound of aluminum, how many liters of aluminum, how many liters of aluminum (D=2.70 g/cmaluminum (D=2.70 g/cm33) are obtained ) are obtained from the cans?from the cans?

1) 1.0 L1) 1.0 L 2) 2.0 L2) 2.0 L 3) 4.0 L3) 4.0 L

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Temperature and Density