General organic and biological chemistry structures off life 5th CH3 classification of matter GOB structures 5th ed

• The temperature difference between boiling and freezing of water are divided into smaller units called degrees.. • On the Celsius scale, there are 100 degrees between the boiling an

Lecture Presentation

Chapter 3 Matter and Energy

Dietitians specialize in

helping others learn

about nutrition and the

need for a balanced diet

Chapter 3 Matter and Energy

Chapter 3 Readiness

Key Math Skills

• Using Positive and Negative Numbers

in Calculations (1.4B)

• Solving Equations (1.4D)

• Interpreting Graphs (1.4E)

• Writing Numbers in Scientific Notation (1.4F)

• Rounding Off (2.3)

Core Chemistry Skills

• Counting Significant Figures (2.2)

• Using Significant Figures in Calculations (2.3)

• Writing Conversion Factors from Equalities (2.5)

• Using Conversion Factors (2.6)

Chapter 3 Readiness

Matter

• is the material that

makes up all things.

Matter is classified according to its composition.

• Pure substances have a fixed or definite

composition.

• Mixtures contain two or more different

substances that are physically mixed but not

chemically combined.

Matter: Pure Substances or Mixtures

A pure substance is

classified as

• a type of matter with a fixed or

definite composition.

• an element that is composed

of one type of atom.

• a compound that is

composed of two or more

elements always combined in

Pure Substances:Elements and Compounds

Elements are pure

substances that contain

only one type of material,

such as the following:

• copper, Cu

• lead, Pb

• aluminum, Al

Elements

A compound contains two

“Table salt” is a compound that contains the elements

sodium and chlorine.

Elements in a Compounds

A mixture is a type of

matter that consists of

• two or more substances

that are physically mixed

but not chemically

In a homogeneous

mixture,

• the composition is

uniform throughout.

• the different parts of the

mixture are not visible.

Homogeneous Mixtures

Breathing mixtures for scuba are

homogeneous mixtures Some

examples are the following:

• nitrox (oxygen and nitrogen gases)

• heliox (oxygen and helium gases)

• trimix (oxygen, helium, and

nitrogen gases)

Chemistry Link to Health: Scuba Breathing Mixtures

In a heterogeneous mixture,

• the composition varies from

one part of the mixture to

another.

• the different parts of the

mixture are visible.

Heterogeneous Mixtures

Classification of Matter

Identify each of the following as a pure substance

Identify each of the following as a pure substance

or mixture:

A pasta and tomato sauce mixture

B aluminum foil pure substance

Solution

Identify each of the following as a homogeneous or

Identify each of the following as a homogeneous or

heterogeneous mixture:

A hot fudge sundae heterogeneous mixture

B shampoo homogeneous mixture

C sugar water homogeneous mixture

D peach pie heterogeneous mixture

Solution

A solid has a definite

Amethyst, a solid, is a purple form of quartz (SiO ).

Solids

• particles that are close

together but mobile.

• particles that move

slowly.

A liquid has a definite

Liquids

Comparison of Solids, Liquids, and Gases

Identify each description as that of a solid, liquid, or gas.

A It has definite volume but takes the shape of the

container.

B Its particles are moving rapidly.

C Its particles fill the entire volume of a container.

D Its particles have a fixed arrangement.

E Its particles are close together but moving randomly.

Study Check

Identify each description as that of a solid, liquid, or gas.

A It has definite volume but takes the shape of the

liquid

C Its particles fill the entire volume of a container. gas

D Its particles have a fixed arrangement solid

E Its particles are close together but moving randomly liquid

Solution

Identify the state of matter for each of the following:

Identify the state of matter for each of the following:

A vitamin tablets solid

C vegetable oil liquid

E air in a tire gas

Solution

Copper has these physical

A physical change occurs

in a substance if there is

• a change in the state.

• a change in the physical

shape.

• no change in the identity

and composition of the

Examples of Physical Changes

Classify each of the following as a change of state or

change of shape:

A chopping a log into kindling wood

B water boiling in a pot

C ice cream melting

D ice forming in a freezer

E cutting dough into strips

Study Check

Classify each of the following as a change of state or

change of shape:

A chopping a log into kindling change of shape

B water boiling in a pot change of state

E cutting dough into strips change of shape

Solution

Chemical properties describe the ability of

a substance

• to interact with other substances.

• to change into a new substance.

When a chemical change takes place, the original

substance is turned into one or more new

substances with new chemical and physical

properties.

Chemical Properties and Changes

During a chemical change, a

new substance forms that has

• a new composition.

• new chemical properties.

• new physical properties.

Sugar caramelizing at a high

Examples of Chemical Changes

Classify each of the following properties as physical or

chemical:

A Ice melts in the sun.

B Copper is a shiny metal.

C Paper can burn.

D A silver knife can tarnish.

E A magnet removes iron particles from a mixture.

Study Check

Classify each of the following properties as physical or

chemical:

A Ice melts in the sun physical

B Copper is a shiny metal. physical

C Paper can burn chemical

D A silver knife can tarnish chemical

E A magnet removes iron particles from a mixture.

physical

Solution

Classify each of the following changes as physical or

chemical:

B ice melting on the street physical

C toasting a marshmallow chemical

E iron rusting in an old car chemical

Solution

Classify each of the following changes as physical or

Temperature

• is a measure of how hot or

cold an object is compared

to another object

• indicates the heat flow from

the object with a higher

temperature to the object

with a lower temperature

Temperature

The temperature scales are Fahrenheit (°F) and

Celsius ( °C).

• The temperature difference between boiling and

freezing of water are divided into smaller units called

degrees.

• On the Celsius scale, there are 100 degrees between

the boiling and freezing points of water

• On the Fahrenheit scale, there are 180 degrees

between the boiling and freezing points of water.

Temperature Scales

Scientists have learned that the coldest

temperature possible is −273 °C On the

Kelvin scale, this is called absolute zero

and is represented as 0 K

The Kelvin scale has

• units called kelvins (K)

• no degree symbol in front of K to represent temperature

Kelvin Temperature Scale

A comparison of the

Fahrenheit, Celsius,

and Kelvin temperature

scales between the

freezing and boiling

points of water.

Temperature Scales

A What is the temperature at which water

A What is the temperature at which water

To convert temperatures between the

Celsius and Fahrenheit scales, we adjust for

the size of the degrees There are

• 100 degrees Celsius between the freezing

and boiling points of water

• 180 degrees Fahrenheit between the

freezing and boiling points of water

Converting between °C and °F

Adjusting for the different freezing points, 0

°C and 32 °F, we can write temperature

equations to convert between Fahrenheit

and Celsius temperatures

Converting between °C and °F

Guide to Calculating Temperature

Example: A person with hypothermia has a

body temperature of 34.8 °C What is that

temperature in degrees Fahrenheit?

STEP 1 State given and needed

Example: A person with hypothermia has a

body temperature of 34.8 °C What is that

temperature in degrees Fahrenheit?

STEP 3 Substitute in the known values

and calculate the new temperature.

Temperature Comparison

On a cold winter day, the temperature is –15

°F What is that temperature in degrees

On a cold winter day, the temperature is –15

°F What is that temperature in degrees

TC = TF − 32 1.8

Solution

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

On a cold winter day, the temperature is –15

°F What is that temperature in degrees

What is the normal body temperature, 37

What is the normal body temperature, 37

What is the normal body temperature, 37 °C,

3.4 Energy

Potential energy is energy stored for use

at a later time

Examples are the following:

• water at the top of a dam

• a compressed spring

• chemical bonds in gasoline, coal, or food

The water at the top of a dam has potential

energy by virtue of its position As the

water falls over and down the dam, the

Potential Energy

Identify the energy in each example as

potential or kinetic:

A rollerblading

B a peanut butter and jelly sandwich

C mowing the lawn

D gasoline in the gas tank

Study Check

Identify the energy in each example as

potential or kinetic:

B a peanut butter and jelly sandwich

potential

D gasoline in the gas tank

potential

Solution

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

Heat is the energy associated with the

• eventually have enough energy to change

Heat and Energy

Energy Comparison

How many calories are obtained from a pat

of butter if it provides 150 J of energy when

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

How many calories are obtained from a pat of butter if it provides 150 J of energy when

metabolized?

STEP 1 State given and needed

quantities.

given unit to the needed unit.

ANALYZE Given Need THE PROBLEM 150 J calories

ANALYZE Given Need THE PROBLEM 150 J calories

Energy Factor

Energy Factor

Solution

How many calories are obtained from a pat of butter if it provides 150 J of energy when

metabolized?

STEP 3 State the equalities and

conversion factors.

Solution

How many calories are obtained from a pat of butter if it provides 150 J of energy when

metabolized?

the needed quantity.

Solution

×

One hour of swimming

uses 2100 kJ of energy.

3.5 Energy and Nutrition

Nutritionists burn food in a calorimeter that

• is used to measure heat transfer.

• consists of a steel container filled with oxygen and a

measured amount of water.

• indicates the heat gained by water, which is the heat lost by

a sample during combustion.

In a calorimeter, the burning of a food sample increases the

temperature of the water, which is used to calculate the

energy value of the food.

Calorimeters

the energy value

for the food.

Calorimeters Measure Energy Values

On food labels, energy is

shown as the nutritional

Calorie, written with a capital

C In countries other than the

United States, energy is

The caloric or energy

value for 1 g of a food

is given in kilojoules (kJ)

or kilocalories (kcal).

The typical energy

values are different for

each food type.

Caloric Food Values

Energy Values for Some Foods

Guide to Calculating Energy from Food

A cup of whole milk contains 13 g of

carbohydrate, 9.0 g of fat, and 9.0 g of

protein How many kilocalories does a cup

of whole milk contain? (Round the final

A cup of whole milk contains 13 g of

carbohydrate, 9.0 g of fat, and 9.0 g of

protein How many kilocalories does a cup of whole milk contain?

quantities ANALYZE Given Need THE PROBLEM 13 g carbohydrate

9.0 g fat

ANALYZE Given Need THE PROBLEM 13 g carbohydrate

9.0 g fat 9.0 g protein kilocalories

Solution

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

A cup of whole milk contains 13 g of

carbohydrate, 9.0 g of fat, and 9.0 g of

protein How many kilocalories does a cup

of whole milk contain?

food type

and calculate kJ or kcal

rounded off to the

tens place.

13 g carbohydrate × 4 kcal/g = 50 kcal

9.0 g fat × 9 kcal/g = 80 kcal

Solution

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

A cup of whole milk contains 13 g of

carbohydrate, 9.0 g of fat, and 9.0 g of

protein How many kilocalories does a cup of whole milk contain?

STEP 3 Add the energy for each food

type to give

the total energy from the food.

Total energy = 50 kcal + 80 kcal + 40

kcal = 170 kcal

Solution

The number of kilocalories

or kilojoules needed in the

daily diet of an adult

depends on gender, age,

and level of physical

activity

A person loses weight

when food intake is less

than energy output

Chemistry Link to Health: Weight Loss

The high specific

heat of water keeps

temperature more

moderate in summer

and winter.

3.6 Specific Heat

Specific heat (SH)

• is different for different substances

• is the amount of heat that raises the

temperature of exactly 1 g of a substance

by exactly 1 °C

• has units of J/g °C in the SI system and

units of cal/g °C in the metric system

Specific Heat

×

Specific Heats of Some Substances

1 When ocean water cools, the surrounding

air

A cools B warms C stays the

same

2 Sand in the desert is hot in the day and

cool at night Sand must have a

A high specific heat B low specific

Study Check

1 When ocean water cools, the surrounding

air

B warms.

2 Sand in the desert is hot in the day and

cool at night Sand must have a

B low specific heat.

Solution

When we know the specific heat of a substance, we can

• calculate the heat lost or gained, by measuring its mass

and temperature change.

• write a heat equation.

Calculations Using Specific Heat

Guide to Calculations Using Specific Heat

What is the specific heat if 24.8 g of a metal

absorbs 275 J of energy and the temperature rises from 20.2 °C to 24.5 °C?

Study Check

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

What is the specific heat if 24.8 g of a metal

absorbs 275 J of energy and the temperature rises from 20.2 °C to 24.5 °C?

STEP 1 State given and needed

Tfinal = 24.5 °C specific heat

ANALYZE Given Need THE PROBLEM 24.8 g metal

275 J energy

Tinitial = 20.2 °C

Tfinal = 24.5 °C specific heat

Solution

What is the specific heat if 24.8 g of a metal

absorbs 275 J of energy and the temperature rises from 20.2 °C to 24.5 °C?

STEP 3 Write the heat equation.

Heat = m × ΔT × SH

and calculate the heat, making

Solution

×

×

A substance

• is melting while it changes from a solid

to a liquid at its melting point (mp).

• is freezing while it changes from a liquid

to a solid at its freezing point (fp).

•Water has a freezing (melting) point of 0

°C

Melting and Freezing

The heat of fusion

• is the amount of heat released when 1 g of

liquid freezes

(at its freezing point)

• is the amount of heat needed to melt 1 g of

solid (at its melting point)

Heat of Fusion

Heat of Fusion for Water

Guide to Calculations Using a Heat Conversion Factor

How many joules are needed to melt 32.0 g of ice at 0 °C?

Study Check

General, Organic, and Biological Chemistry: Structures of Life, 5/e

Karen C Timberlake

© 2016 Pearson Education, Inc.

How many joules are needed to melt 32.0 g

of ice at 0 °C?

STEP 1 State given and needed quantities.

given quantity to the

needed quantity.

ANALYZE Given Need THE PROBLEM 32.0 g ice

0 °C joules to melt ice

ANALYZE Given Need THE PROBLEM 32.0 g ice

0 °C joules to melt ice

Heat of Fusion

Heat of Fusion

Solution