ClassiÞcations of Matter - Mister Chemistry · ClassiÞcations of Matter ... Law of Definite Proportions ... what is the percent by mass of hydrogen in the compound that is formed

Classifications of Matter

Matter is anything that occupies space and has mass.

mass - a measure of the quantity of matter

Volume - space

Physical and Chemical Properties of Matter

Properties

A set of characteristics by which a substance can be recognized

can be measured and observed without changing the composition or identity of a substance

densitycolor odortaste

hardnessmelting pointboiling point

Physical Property

Extensive property

depends on amount of material; mass and volume are examples of extensive properties

Intensive property

does not depend on amount of material; density and temperature are examples of intensive properties

mass,volume, length....

density, temperature...

requires a chemical change in order to be observed

the ability of a substance to combine with or change into one or more substances.

old substance gone

new substance formed

Chemical Property

has its own definite shape an volume. Tightly packed particles make solids incompressible.

The Three States of Matter

has a constant volume but conforms to the shape of its container. Particles are not rigidly held in place and are less closely packed.

Solid

Liquid

gasconforms to both the shape and the volume of its container. Particles are very far apart which makes gases very compressible.

solid liquid gas

Physical change

alters a substance without changing the composition

Tearing paperMelting waxPhase changes

examples:

Chemical changeone or more substances changing into new substances

words that signify a chemical change:

BurningRottingRustingExploding

Cellular respirationexamples:

Evidence of a Chemical ReactionThe following are indicators that a chemical reaction has taken place:

- Color change

- Effervescence

– Evolution of gas

Evidence of a Chemical Reaction cont.

- Evolution of light

- Odor

– Formation of a Precipitate

Chemical Reactions

Chemical bonds have been broken and new chemical bonds have been formed

2H2 + O2 2H2O(g) (g) (g)

Chemical Reactions

2H2 + O2 2H2O(g) (g) (g)

Reactants: elements or compounds to the left of the arrow that combine together in a chemical reaction

Chemical Reactions

2H2 + O2 2H2O(g) (g) (g)

Reactants: elements or compounds to the left of the arrow that combine together in a chemical reaction

Products: elements or compounds to the right of the arrow that produced in a chemical reaction

Joseph Priestley and Antoine–LaurentLavoisier — 18th century- Demonstrated that combustion is a reaction between matter and oxygen

Law of Conservation of Mass- matter can neither be created nor destroyed

Massreactants

Massproducts

=

2 Hg

216 g 16 g 200 g

Start: 0 0 216 g

200 g Finish: 0 16 g

2 HgO O2 +

The thermal decomposition of mercury II oxide.

from a laboratory process designed to separate water into hydrogen and oxygen, a student collected 10.0 g of hydrogen and 79.4 g of oxygen. How much water was originally involved in the process?

practice problem 6

2H2 + O2 (g) (g)(g)2H2O

10g 79.4g

Start:

Finish:

?89.4g

a student carefully places 15.6 g of sodium in a reactor supplied with an excess quantity of chlorine gas. When the reaction was complete, the student obtained 39.7 g of sodium chloride. How many grams of chlorine gas reacted? How many grams of sodium reacted ?

practice problem 7

excess 39.7 gFinish: 0

2Na Cl2 2NaCl+

15.6 gStart: excess24.1g

Matter

Mixture Substance

Homogeneousmixtures

Heterogeneousmixtures

Compounds

Elements

Matter

Mixture Substance

Homogeneousmixtures

Heterogeneousmixtures

Compounds

Elements

click on words for definitions

Based on the difference in boiling points of the mixed substances

Distillation

Separating Mixtures

CrystallizationResults in the formation of solid particles of a substance from a solution containing the dissolved stance

Chromatographyseparates the components of a mixture (mobile phase) on the basis of the tendency of each to travel across the surface of another material (stationary phase)

Periodic Table of the Elements

Chemical Symbols

abbreviations for the names of the elements

the first letter is always capitalized

O, Al, C, Cl, H, He…….

An elements position on the periodic gives indications of its various physical and chemical

properties

Main groupsgroup numbers indentified by suffix A

Main group metalsAlkali metals Alkaline earth metals

NonmetalsHalogens Noble gases

transition metalsLanthanidesActinides

transition metalsLanthanides

What makes water,

H2O

water ?

1 L2 L

+ (g)(l) (g)O22H22H2O

+

32.0 g4.0 g

+ (g)(l) (g)O22H22H2O

+

36.0 g

+ (g)(l) (g)O2HH2O

+

16.0 g2.0 g18.0 g

18.0 g H2O

18.0 g H2O

16.0 g O

2.0 g Hx 100 %

x 100 % = 88.9 % O

= 11.1 % H

+ (g)(l) (g)O2HH2O

32.0 g O

4.0 g H

+ (g)(l) (g)O22H22H2O

36.0 g H2O

36.0 g H2O

x 100 %

x 100 % = 88.9 %

= 11.1 %

Joseph Proust — 18th century

Chemistry Timeline

Law of Definite Proportions- different samples of the same compound always contain its constituent elements in the same proportions by mass

- the proportions can be found by calculating the percent by mass

Percent by mass

based on the law of conservation of mass

Masscompound

the sum of the Masseselements

=

% by mass =mass of the element

mass of the compoundx 100 %

20.00 g of Sucrose is a compound made up of Carbon, Hydrogen and Oxygen

Example page 75

Carbon

Hydrogen

Oxygen

8.44 g

1.30 g

10.26 g

20.00 g Sucrose

8.44 g C

1.30 g H

10.26 g O20.00 g Sucrose

20.00 g Sucrose

20.00 g Sucrosex

x

x

100%

100%

100%

= 42.2 % C

=

=

6.50 % H

51.30 % O

500.0 g of Sucrose is a compound made up of Carbon, Hydrogen and Oxygen

Example page 75

Carbon

Hydrogen

Oxygen

211.0 g

32.5 g

256.5 g

500.0 g Sucrose

211.0 g C

32.5 g H

256.5 g O500.0 g Sucrose

500.0 g Sucrose

500.0 g Sucrosex

x

x

100%

100%

100%

= 42.2 % C

=

=

6.50 % H

51.30 % O

A 78.0 g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound ?

practice problem 20

% Hydrogen =12.4 g H

78.0 g compoundx 100% = 15.9 % H

If 1.0 g of hydrogen reacts completely with 19.0 g of fluorine, what is the percent by mass of hydrogen in the compound that is formed ?

practice problem 21

% Hydrogen =1.0 g H

20.0 g compoundx 100% = 5.0 % H

19.0 g F + 1.0 g H = 20.0 g compound

If 3.5 g of X reacts with 10.5 g of Y, what is the percent by mass of X in the compound that is formed ?

practice problem 22

% X =3.5 g X

14.0 g compoundx 100% = 25 % X

3.5 g X + 10.5 g Y = 14.0 g compound

% Y =10.5 g Y

14.0 g compoundx 100% = 75 % Y

Two unknown compounds are tested. Compound 1 contains 15.0 g hydrogen and 120.0 g oxygen. Compound 2 contains 2.0 g hydrogen and 32.0 g oxygen. Are the compounds the same ?

practice problem 23

Two unknown compounds are tested. Compound 1 contains 15.0 g hydrogen and 120.0 g oxygen. Compound 2 contains 2.0 g hydrogen and 32.0 g oxygen. Are the compounds the same ?

practice problem 23

% H =15.0 g H

135.0 g compoundx 100% = 11.1 % H

% O =120.0 g O

135.0 g compoundx 100% = 88.9 % O

Two unknown compounds are tested. Compound 1 contains 15.0 g hydrogen and 120.0 g oxygen. Compound 2 contains 2.0 g hydrogen and 32.0 g oxygen. Are the compounds the same ?

practice problem 23

% H =2.0 g H

34.0 g compoundx 100% = 5.9 % H

% O =32.0 g O

34.0 g compoundx 100% = 94.1 % O

11.1 % H

88.9 % O

5.9 % H

94.1 % O

Two unknown compounds are tested. Compound 1 contains 15.0 g hydrogen and 120.0 g oxygen. Compound 2 contains 2.0 g hydrogen and 32.0 g oxygen. Are the compounds the same ?

practice problem 23

Compound 1

Compound 2

No these are not the same compounds

John Dalton — 19th century

Chemistry Timeline

Law of Multiple Proportions- if two elements can combine to form more than one compound, the masses of one element that combine with a fixed mass of the other elements are in ratios of small whole numbers

Mass of nitrogen that combines with 1g of oxygen

Example

Compound 1 1.750g

Compound 2 0.8750g

Compound 3 0.4375g0.4375g

0.4375g

0.4375g=

=

=

4

2

1

Whole number ratios

mass ratio compound

2

1 64.20

47.27

35.80

52.73

1.793 g Cu/ 1 g Cl

0.8964 g Cu/ 1 g Cl= 2

% Cu % Cl

64.20

47.27 52.73

35.80

mass copper (g) in 100.0 g of compound

mass Chlorine (g) in 100.0 g of compound

1.793 g Cu/ 1 g Cl

0.8964 g Cu/ 1 g Cl

mass Cumass Chlorine

Multiple Proportions

(slides that follow are linked to earlier ones)

a substance is form of matter that has a definite or constant composition and distinct properties, for example

waterammoniatable sugargoldoxygen

a mixture is a combination of two or more substances in which the substances retain their distinct indentities, for example

airmilkcement

the composition of a homogeneous mixture is the same throughout, for example

sugar dissolved in water

a mixture of nonuniform composition is a heterogeneous mixture, for example

airSand and iron filings

an element is a substance that cannot be separated into simpler elements by

chemical means

a compound is a substance composed of atoms of two or more elements chemically united in fixed

proportions