Chapter 1 1.6 to 1.9 Chemical Foundations. Chapter 1 Table of Contents Return to TOC Copyright ©...

Chapter 11.6 to 1.9

Chemical Foundations

Chapter 1

Table of Contents

Return to TOC

Copyright © Cengage Learning. All rights reserved

1.6 Dimensional Analysis

1.7Temperature

1.8Density

1.9Classification of Matter

Section 1.6

Dimensional Analysis


• Use when converting a given result from one system of units to another. To convert from one unit to another, use the

equivalence statement that relates the two units. Derive the appropriate unit factor by looking at the

direction of the required change (to cancel the unwanted units).

Multiply the quantity to be converted by the unit factor to give the quantity with the desired units.

Section 1.6



Example #1

A golfer putted a golf ball 6.8 ft across a green. How many

inches does this represent?

To convert from one unit to another, use the equivalence

statement that relates the two units.

1 ft = 12 in

The two unit factors are:

Section 1.6



• Derive the appropriate unit factor by looking at the direction of the required change (to cancel the unwanted units).

Example #1

A golfer putted a golf ball 6.8 ft across a green. How many inches does this represent?

Section 1.6



• Multiply the quantity to be converted by the unit factor to give the quantity with the desired units.

Example #1

A golfer putted a golf ball 6.8 ft across a green. How many inches does this represent?

Section 1.6



Example #2

An iron sample has a mass of 4.50 lb. What is the mass of this sample in grams?

(1 kg = 2.2046 lbs; 1 kg = 1000 g)

Copyright © Houghton Mifflin Company. All rights reserved. 1–26

• What data would you need to estimate the money you would spend on gasoline to drive your car from New York to Chicago? Provide estimates of values and a sample calculation.

React 3

Section 1.6



Concept Check

What data would you need to estimate the money you would spend on gasoline to drive your car from New York to Los Angeles? Provide estimates of values and a sample calculation.

l Because you never learned dimensional analysis, you have been working at a fast food restaurant for the past 35 years wrapping hamburgers. Each hour you wrap 184 hamburgers. You work 8 hours per day. You work 5 days a week. you get paid every 2 weeks with a salary of $840.34. How many hamburgers will you have to wrap to make your first one million dollars?

Examples

l A senior was applying to college and wondered how many applications she needed to send. Her counselor explained that with the excellent grade she received in chemistry she would probably be accepted to one school out of every three to which she applied. She immediately realized that for each application she would have to write 3 essays, and each essay would require 2 hours work. Of course writing essays is no simple matter. For each hour of serious essay writing, she would need to expend 500 calories which she could derive from her mother's apple pies. Every three times she cleaned her bedroom, her mother would make her an apple pie. How many times would she have to clean her room in order to gain acceptance to 10 colleges?

Units to a Powerl How many m3 is 1500 cm3?

1500 cm33 1 m100 cm

1 m100 cm

1 m100 cm

1500 cm33 1 m

100 cm

33

Units to a Powerl How many cm2 is 15 m2?l 36 cm3 is how many mm3?

Section 1.7

Temperature

Return to TOC


• Fahrenheit• Celsius• Kelvin

Three Systems for Measuring Temperature

Section 1.7

Temperature

Return to TOC


The Three Major Temperature Scales

Section 1.7

Temperature

Return to TOC


Converting Between Scales


• At what temperature does C = F? • Prove your answer.

React 4

ºC

ºF 9

5

0ºC is not 0ºF

ºC

ºF

(0,32)= (C1,F1)

ºC

ºF

(0,32) = (C1,F1)

(100,212) = (C2,F2)

Section 1.7

Temperature

Return to TOC


Exercise

At what temperature does C = F?

Section 1.7

Temperature

Return to TOC


• Since °C equals °F, they both should be the same value (designated as variable x).

• Use one of the conversion equations such as:

• Substitute in the value of x for both TC and TF. Solve for x.

Solution

Section 1.7

Temperature

Return to TOC


Solution

Section 1.8

Density

Return to TOC


• Mass of substance per unit volume of the substance.

• Common units are g/cm3 or g/mL.

Section 1.8

Density

Return to TOC


Example #1

A certain mineral has a mass of 17.8 g and a volume of 2.35 cm3. What is the density of this mineral?

Section 1.8

Density

Return to TOC


Example #2

What is the mass of a 49.6-mL sample of a liquid, which has a density of 0.85 g/mL?

Section 1.9

Classification of Matter

Return to TOC


• Anything occupying space and having mass.• Matter exists in three states.

Solid Liquid Gas

Matter

Section 1.9


Return to TOC


The Three States of Water

Section 1.9


Return to TOC


• Rigid• Has fixed volume and shape.

Solid

Section 1.9


Return to TOC


Structure of a Solid

http://college.cengage.com/chemistry/zumdahl/chemistry/7e/

assets/students/protected/fae/index.html?layer=act&src=qtiw

orkflowflash_1_11.xml&w=750&h=434

Click below for visual concept while in play mode

http://college.cengage.com/chemistry/zumdahl/chemistry/7e/assets/students/protected/fae/index.html?layer=act&src=qtiworkflowflash_1_11.xml&w=750&h=434



Section 1.9


Return to TOC


• Has definite volume but no specific shape.• Assumes shape of container.

Liquid

Section 1.9


Return to TOC


Structure of a Liquid

Texthttp://college.cengage.com/chemistry/zumdahl/chemistry/7e/assets/students/prote

cted/fae/index.html?layer=act&src=qtiworkflowflash_1_15.xml&w=750&h=434



Section 1.9


Return to TOC


• Has no fixed volume or shape.• Takes on the shape and volume of its

container.

Gas

Section 1.9


Return to TOC


Structure of a Gas

http://college.cengage.com/chemistry/zumdahl/chemistry/7e/assets

/students/protected/fae/index.html?layer=act&src=qtiworkflowflas

h_1_14.xml&w=750&h=434




Section 1.9


Return to TOC


• Have variable composition.

Mixtures

Homogeneous Mixture

Heterogeneous Mixture

Having visibly indistinguishable parts; solution.

Having visibly distinguishable parts.

Section 1.9


Return to TOC


Homogeneous Mixtures

http://college.cengage.com/chemistry/zumdahl/chemistry/7e/assets/students/pr

otected/fae/index.html?layer=act&src=qtiworkflowflash_1_13.xml&w=750&h

=434




Section 1.9


Return to TOC


Homogeneous vs. Heterogeneous Mixtures

http://college.cengage.com/chemistry/zumdahl/chemistry/7e/assets/students/pr

otected/fae/index.html?layer=act&src=qtiworkflowflash_1_10.xml&w=750&

h=434




Section 1.9


Return to TOC


Compound vs. Mixture

http://college.cengage.com/chemistry/zumdahl/chemistry/7e/assets/students/protected/fae

/index.html?layer=act&src=qtiworkflowflash_1_12.xml&w=750&h=434



Section 1.9


Return to TOC


Concept Check

Which of the following is a homogeneous mixture?

Pure water Gasoline Jar of jelly beans Soil Copper metal

40

Chapter OnePrentice Hall © 2005 Hall © 2005General Chemistry 4th edition, Hill, Petrucci, McCreary, Perry

Key Terms: Properties• A physical property is displayed

by a sample of matter without undergoing any change in the composition of the matter.٭ Physical properties include mass,

color, volume, temperature, density, melting point, etc.

• Chemical property – displayed by a sample of matter as it undergoes a change in composition.٭ Flammability, toxicity, reactivity,

acidity are all chemical properties.

Copper is red-brown,

opaque, solid: physical

properties.

Ethanol is flammable: a

chemical property.

Section 1.9


Return to TOC


• Change in the form of a substance, not in its chemical composition. Example: boiling or freezing water

• Can be used to separate a mixture into pure compounds, but it will not break compounds into elements. Distillation Filtration Chromatography

Physical Change

Section 1.9


Return to TOC


• A given substance becomes a new substance or substances with different properties and different composition. Example: Bunsen burner (methane reacts with

oxygen to form carbon dioxide and water)

Chemical Change

43


Key Terms: Properties• In a physical change, there is no

change in composition.• No new substances are formed.

٭ Examples include: evaporation; melting; cutting a piece of wood; dissolving sugar in water.

• In a chemical change or chemical reaction, the matter undergoes a change in composition.

• New substances are formed.٭ Examples include: burning

gasoline; dissolving metal in acid; spoilage of food.

The liquid fuel evaporates: a

physical change.

The vapor burns,

combining with oxygen: a chemical change.

Section 1.9


Return to TOC


Concept Check

How many of the following are examples of a chemical change?

Pulverizing (crushing) rock salt Burning of wood Dissolving of sugar in water Melting a popsicle on a warm summer day

Section 1.9


Return to TOC


The Organization of Matter

46


Classifying Matter

Figure 1.9

Atoms Molecules

make up

ALL MATTER

which exists as

Substances Mixtures

which may be

Elements Compounds Heterogeneous

which may be

Homogeneous

Pure

The Organization of MatterThe Organization of Matter

MatterMatter

Mixtures:a) Homogeneous (Solutions)b) Heterogeneous

Pure SubstancesPure Substances

Compounds ElementsElements

AtomsAtoms

NucleusNucleus ElectronsElectrons

Protons NeutronsNeutrons

QuarksQuarks QuarksQuarks

48


Classifying Matter

• A (pure) substance has a definite or fixed composition that does not vary from one sample to another.

• All substances are either elements or compounds.

• An element cannot be broken down into other simpler substances by chemical reactions.٭ About 100 elements known at this time

٭ Each element has a chemical symbol: O, H, Ag, Fe, Cl, S, Hg, Au, U, etc.

• A compound is made up of two or more elements in fixed proportions, and can be broken down into simpler substances.٭ Carbon dioxide, sodium chloride, sucrose (sugar), etc.

49


Classifying Matter• A mixture does not have a fixed composition.

• A homogeneous mixture has the same composition throughout, though the composition of different homogeneous mixtures may vary.٭ Soda pop, salt water, 14K gold, and many plastics are

homogeneous mixtures.

٭ 10K gold and 14K gold have different compositions but both are homogeneous.

• A heterogeneous mixture varies in composition and/or properties from one part of the mixture to another.٭ Adhesive tape, CD, pen, battery, chair, and people are

examples of heterogeneous mixtures.

• Most everyday “stuff” consists of mixtures.


The Organization of Matter

Phase Phase DifferencesDifferences

SolidSolid – definite volume and shape; particles packed in fixed positions.LiquidLiquid – definite volume but indefinite shape; particles close together but not in fixed positions

GasGas – neither definite volume nor definite shape; particles are at great distances from one another

PlasmaPlasma – high temperature, ionized phase of matter as found on the sun.

Properties of MatterProperties of Matter

Volume

MassEnergy Content (think Calories!)

Extensive propertiesExtensive properties depend on the amount of matter that is present.

Intensive propertiesIntensive properties do not depend on the amount of matter present.

Melting point

Boiling point

Density

Separation of a MixtureSeparation of a Mixture

The constituents of the mixture retain The constituents of the mixture retain their identity and may be separated their identity and may be separated by physical means.by physical means.

Separation of a MixtureSeparation of a Mixture

The components of The components of dyes such as ink dyes such as ink may be separated may be separated by paper by paper chromatography.chromatography.


Figure 1.15b The Paper Acts as a Wick to Draw up the Liquid


Figure 1.15c Component with the Weakest Attraction for the Paper Travels Faster

Separation of a Mixture Separation of a Mixture by Distillationby Distillation

Separation of a CompoundSeparation of a CompoundThe Electrolysis of water

Water Hydrogen + Oxygen

2 H2O 2 H2 + O2

Reactant Products

Compounds must be separated by chemicalchemical means.

With the application of electricity, water can be separated into its elements


• Sketch a magnified view (showing atoms/molecules) of each of the following:– a heterogeneous mixture of two different

compounds.– a homogeneous mixture of an

element and a compound.

React 5

Chapter 1 1.6 to 1.9 Chemical Foundations. Chapter 1 Table of Contents Return to TOC Copyright ©...

Documents

Transcript of Chapter 1 1.6 to 1.9 Chemical Foundations. Chapter 1 Table of Contents Return to TOC Copyright ©...