Chemistry: The Science of Matter Ch 1 Chemistry Science that - - PowerPoint PPT Presentation

Chemistry: The Science of Matter

■ Ch 1

■ Chemistry

■ Science that investigates & explains the

structure and properties of matter

■ Matter

■ Anything that takes up space and has mass

■ Mass

■ Amount of matter that an object contains ■ (Weight is the force of gravity on the mass)

States of matter

■ Solid ■ Liquid ■ Gas

Solid

■ Particles are tightly packed usually in a

regular arrangment

■ Particles vibrate (jiggle) but do not move past

each other

■ Not easily compressed ■ Fixed volume and fixed shape

Liquid

■ Particles close together with no regular

arrangement

■ Particles vibrate, move past each other by

sliding

■ Not easily compressed ■ Assumes shape of container, fixed volume

Gas

■ Particles separate with no regular

arrangement

■ Particles vibrate and move freely ■ Easily compressed ■ Assumes shape and volume of container

What is not matter?

• A. Water
• B. Heat
• C. Salt
• D. Hair

What is matter?

• A. Radio Waves
• B. Aspirin
• C. Light
• D. Magnetic Fields

What is matter made of?

■ It is a pure SUBSTANCE

OR

■ It is a MIXTURE

A Pure Substance

■ A sample of matter that has the same fixed

composition and definite physical and chemical properties

A Substance can be a…

■ Compound

Or a

■ Element

An Element is a substance

■ Cannot be broken down into simpler

substances

■ Simplest form and basic building block of

matter

■ 118 Elements ■ 90 naturally occurring (All in first 92 except

43-Technetium and 61-Promethium)

■ Found on The Periodic Table ■ Each element has a symbol

A Compound is a substance

■ Can be broken down into simpler substances ■ Chemical combination of two or more different

elements joined together in fixed proportions

■ The relative amounts of the elements never

change in a compound

■ Properties of compounds are different from

the properties of the elements that compose the compound

■ More than 10 million compounds

A compound has a Chemical Formula

■ Combination of chemical symbols that show

what elements make up a compound and the number of atoms of each element

Element!!!

Name the element or symbol

IRON

• A. Ir

B.Fe

• C. I

Hydrogen

A.Hg B.H C.Hy

Na

A.Sodium B.Naturium C.Rhodium

Hg

A.Helligrium B.Mercury C.Antimony

Pure Substance

■Is it an Element or a

Compound??

Fe

• A. Element
• B. Compound

H2O

• A. Element
• B. Compound

NaCl

• A. Element
• B. Compound

Carbon

• A. Element
• B. Compound

Silver Nitrate

• A. Element
• B. Compound

Hydrochloric Acid

• A. Element
• B. Compound

Chemical Formula of a Compound

■Count the number of

atoms

H20

How many atoms of Oxygen (O)?

• A. 0
• B. 1
• C. 2
• D. 3

H20

How many atoms of Hydrogen (H)?

• A. 0
• B. 1
• C. 2
• D. 3

K2C4H4O6

How many atoms of carbon (C)?

• A. 1
• B. 2
• C. 4
• D. 6

Mg(OH)2

How many atoms of Hydrogen (H)?

• A. 0
• B. 1
• C. 2
• D. 3

Mg(OH)2

How many atoms of Oxygen (O)?

• A. 0
• B. 1
• C. 2
• D. 3

H2(SO)4

How many atoms of Sulfur (S)?

• A. 0
• B. 1
• C. 2
• D. 4

A Mixture …

■ Pure substances that exist together without

chemically combining

■ Retains the properties of each of its

components

■ It does not have fixed compositions-relative

amounts of each pure substance can vary

■ The basic identity of each substance is not

changed

■ It can be separated by physical processes

Two types of Mixtures

■ Heterogeneous-different composition

throughout

■ Hetero--different

■ Homogeneous-same composition throughout

■ Homo—the same ■ Also called a solution ■ May look like a pure substance but can vary

(tea with a little sugar or tea with lots of sugar)

A Solution is a homogeneous mixture

■ Examples –

■ Gas in gas – air ■ Gas in liquid – soda ■ Liquid in liquid – antifreeze ■ Solid in liquid – seawater ■ Solid in solid - brass (An alloy is a solid homogeneous

mixture) ■ Solute-the substance being dissolved ■ Solvent-the substance that dissolves the solute ■ Aqueous solution -solvent is water

Homogeneous Mixture

■ Solution

■ Mixture with particle size 0.1-2 nanometers ■ Particles are at the molecule or ion level ■ May have a color but will be transparent (can

see through)

■ Light passes through with no scattering of light ■ Cannot be separated by filtration, may be

separated by distillation

■ Examples – air with no clouds, vinegar, oil,

sugar and water mixture

Heterogeneous Mixture??

■

Colloid (also know as colloidal dispersions)

■ Particle size greater between 2 and 1000 nanometers ■ Particles consist of clumps of molecules ■ Particles are usually not visible to the naked eye ■ Particles large enough to scatter light (Tyndall effect) ■ Looks homogeneous to the naked eye ■ Do not separate upon standing ■ Cannot be separated by filtration ■ May appear murky or opaque ■ Might be separated by a centrifuge or a semipermeable

membrane

■ Types

■ Gel – liquid in a solid (jelly, stick deodorant) ■ Emulsion – two liquids (milk, mayonnaise) ■ Aerosol – solid or liquid in a gas (fog, smoke)

Heterogeneous Mixture

■ Suspension

■ Particle size greater than 1000 nanometers ■ Particles are visible to the naked eye ■ Murky or opaque ■ Settle upon standing ■ Does not transmit light ■ Can be separated by filtration

What type of mixture?

Orange juice (with lots of pulp)

• A. Homogeneous
• B. Heterogeneous

Vegetable Soup

A.Homogeneous B.Heterogeneous

Homo- means

• A. Same
• B. Different

Diet Coke

• A. Homogeneous
• B. Heterogeneous

Air

• A. Homogeneous
• B. Heterogeneous

Is it a Substance

• r a Mixture?

Iron

• A. Substance
• B. Mixture

Sand mixed with sugar

• A. Substance
• B. Mixture

Water

• A. Substance
• B. Mixture

Air

• A. Substance
• B. Mixture

Blood

• A. Substance
• B. Mixture

Properties of Matter

Properties of Matter – Intensive or Extensive

■

Intensive

■ Properties that do not depend on the amount of matter

present (independent of the mass)

■ Color ■ Odor ■ Luster – shiny ■ Malleability – ability to beat into thin sheets ■ Ductility – ability to be drawn into thin wires ■ Conductivity – ability of a substance to allow the flow of

electricity

■ Hardness – how easily it can be scratched ■ Melting or Freezing Point ■ Boiling Point ■ Density ■ Solubility

Properties of Matter – Intensive or Extensive

■ Extensive

■ Properties that do depend on the amount of

matter present

■ Mass ■ Weight ■ Volume ■ Length

Properties of Matter

■ Can be QUALITATIVE

■ No measurement necessary (Quality)

■ “The solid is hard.”

■ Can be QUANTITATIVE

■ Uses measurement (Quantity)

■ “Iron has a density of 7.86 g/ml.”

The temperature is 98o F

• A. Qualitative
• B. Quantitative

Sucrose is composed of C, H, & O

• A. Qualitative
• B. Quantitative

The sky is blue.

• A. Qualitative
• B. Quantitative

I weight 99 pounds.

• A. Qualitative
• B. Quantitative

???????

What are some properties that might be used to identify matter?

???????????????????

Color Solid, liquid, gas Does it burn? Does it dissolve in water? What happens when you mix it with ?

Physical Properties

■ Characteristics that matter exhibits without any

change in its identity

■ Solubility (dissolves) ■ Physical State (solid, liquid, gas) ■ Temperature at which it changes from one state to

another (Melting Point, Boiling point)

■ Color ■ Density (mass/volume) ■ Electrical Conductivity ■ Odor ■ Viscosity (how easily it flows)

Physical Changes

■ Change in matter that does not involve a

change in the identity of individual substances

■ You can separate a mixture using Physical

Changes

■ The same compounds are present before

and after the physical change

Examples of Physical Changes

■ Boiling ■ Freezing ■ Melting ■ Subliming ■ Evaporating ■ Dissolving ■ Mixing ■ Condensation ■ Precipitation

How can you separate sugar and sand using physical changes?

Chemical Properties

■ Can only be observed

when there is a change in the composition of the substance

■ Describes the ability of

a substance to react with other substances

• r decompose

Chemical Properties

■ Can only be observed when there is a change

in the composition of the substance

■ Describes the potential or ability of a

substance to undergo a chemical change

Chemical properties

■ Rusts ■ No reaction ■ Prevents oxidation ■ Breaks down in light ■ Formation of gases ■ Evolution of light and heat ■ Absorption of energy ■ Flammability ■ Radioactivity ■ Sensitivity to light ■ Toxicity

Chemical Change (Chemical Reaction)

■ The change of one or more substances into

• ther substances

■ Involves a rearrangement of the atoms ■ Involves some sort of energy change

Clues that a chemical change has

• ccurred

■

• 1. Gas is produced

■ CO2 – flame is extinguished! ■ O2 – flame is reignited ■ H2 – “pop”

■

• 2. Light is produced

■ Magnesium + oxygen →

■

• 3. Temperature change

■

Calcium + hydrochloric acid → calcium chloride + hydrogen gas

■

• 4. Color change (not normal!)

Lead nitrate + potassium iodide → lead iodide (ppt) + potassium nitrate

■

• 5. Precipitate formed

■ See above

■

• 6. Odor changes

■ Barium hydroxide + ammonium chloride → ammonium

hydroxide and barium chloride

Energy changes

■ Exothermic

■ Give off heat energy (feels hot) ■ Dynamite-explosion of nitroglycerin

■ Endothermic

■ Absorb heat energy (feels cold) ■ photosynthesis

Burning a log

• A. Exothermic
• B. Endothermic

Law of conservation of Mass

■ In a chemical change, matter is neither

created nor destroyed

■ Atoms do not disappear ■ The amount of mass at the beginning of the

chemical change must equal the amount of mass at the end of the chemical change

■

In the procedure shown above, a calcium chloride solution is mixed with a sodium sulfate solution to

■

create the products shown. Which of the following is illustrated by this activity?

■

F The law of conservation of mass

■

G The theory of thermal equilibrium

■

H The law of conservation of momentum

■

J The theory of covalent bonding

■ When 50 mL of isopropyl alcohol (39.5 g) is

added to 50 mL of water (50 g), the mixture will have a volume of 98 mL. What is the mass in grams of this mixture? Record and bubble in your answer to the nearest tenth on the answer document.

Copper (Cu) and sulfur (S) were heated in a covered container. After the reaction was complete, the unreacted sulfur was removed. The table contains the results of the investigation. How much sulfur, in grams, failed to react with the copper? Record and bubble in your answer to the nearest hundredth on the answer document. Copper (Cu) and sulfur (S) were heated in a covered container. After the reaction was complete, the unreacted sulfur was removed. The table contains the results of the investigation. How much sulfur, in grams, failed to react with the copper? Record and bubble in your answer to the nearest hundredth on the answer document.

■ If all the reactants in a chemical reaction are

completely used, which of the following

■ statements accurately describes the relationship

between the reactants and the

■ products? ■ F The products must have a different physical state

than the reactants.

■ G The total mass of the reactants must equal the total

mass of the products.

■ H The reactants must contain more complex

molecules than the products do.

■ J The density of the reactants must equal the density

• f the products.

■ When 127 g of copper reacts with 32 g of

• xygen gas to form copper (II) oxide, no

copper or oxygen is left over. How much copper (II) oxide is produced?

■ F 32 g ■ G 95 g ■ H 127 g

■ According to the law of conservation of mass,

how much zinc was present in the zinc carbonate?

■ A 40 g ■ B 88 g ■ C 104 g ■ D 256 g

Physical or Chemical property??

Baking Soda is a white powder

• A. Physical property
• B. Chemical property

Fluorine is a highly reactive element.

• A. Physical property
• B. Chemical property

Aluminum bends easily

• A. Physical property
• B. Chemical property

Physical or Chemical Change?

A pan of water boils on the stove.

• A. Physical change
• B. Chemical change

A match lights when struck.

• A. Physical change
• B. Chemical change

Ice cream melts

A.Physical Change B.B. Chemical Change

Sodium reacts with water

A.Physical Change B.Chemical Change

Baking soda bubbles and gives off carbon dioxide when it is moistened

• A. Physical change
• B. Chemical change

Change from solid to liquid & from gas to liquid

A.Physical Change B.Chemical Change

Squeeze a HOT HANDS and the pad warms up.

• A. Physical change
• B. Chemical change

A lump of gold is pounded into a large, thin sheet.

• A. Physical change
• B. Chemical change

Air is squeezed by a pump and forced into a tire.

• A. Physical change
• B. Chemical change

Disgestion-Physical or Chemical?

■ Physical

■ Chewing breaks food into smaller pieces

Digestion-Physical or Chemical

■ Chemical

■ Large molecules (like starch and proteins) are

changed into simple sugars and amino acids

■ Enzymes like pepsin and amylase help

Oxidation-Physical or Chemical?

■ Chemical

■ Example when iron and oxygen form a new

substance--rust

The Rock Cycle-Physical or Chemical?

Rock Cycle

■ Sediments are deposited-Physical ■ Sediments (under pressure) turn into

sedimentary rocks-Physical

■ Sedimentary rocks (under heat and pressure)

turn into metamorphic rocks- Chemical

■ Metamorphic rocks melt into magma-Physical

& Chemical

■ Magma cools and forms new rock with new

minerals-Physical & Chemical