Review for Physical Science Exam Grade 8

Types of Measurements 1. Length a. The distance from one point to another point. b. Base unit is the meter (m). c. Tool is the metric ruler. 2. Volume a. The amount of space a substance occupies. b. Base unit is the liter (L). c. Tools: metric ruler for regular solids or graduated cylinder for liquids.

3. Mass a. The amount of matter in a substance. b. Base unit - kilogram (kg). c. Tool is the balance. 4. Weight a. A measure of gravitational force on an object. b. Unit is the newton (N). c. Tool is the scale.

5. Time a. How long an event takes to occur. b. Unit is the second (s). c. Tool is the clock (stopwatch). 6. Temperature a. The amount of kinetic energy a substance has. b. SI unit is the Kelvin (K). c. Tool is the thermometer.

7. Density a. How compacted the matter is in a substance. b. Units can be g/mL, g/cm3, kg/m3. c. Density is a derived unit (it is made up of other types of measurement). d. D = m / v e. Objects float if their density is less than the density of the fluid they are in.

7. Density a. How compacted the matter is in a substance. b. Units can be g/mL, g/cm3, kg/m3. c. Density is a derived unit (it is made up of other types of measurement). d. D = m / v e. Objects float if their density is less than the density of the fluid they are in.

Scientific Experimentation controlled experiment -Only one variable should be changed Manipulated (independent) – changed by the experimenter. Responding (dependent) – the effect.

Matter Matter = any material substance with Mass & Volume

CLASSIFICATION OF MATTER

The Organization of Matter Matter Mixtures Pure Substances Heterogeneous Homogeneous Compounds Elements

The Organization of Matter

Matter comes in 3 phases Solid Liquid Gas

Solid Definite Shape Definite Volume

Liquid Indefinite Shape – takes the shape of the container Definite Volume

Gas Indefinite Shape – takes the shape of the container Indefinite Volume – can expand and be compressed

Plasma Plasma : a high energy gaseous state of matter. It is very unstable . Particles are moving extremely fast, free energy Most abundant phase of matter Only present under extremely hot/energetic situations Example: Sun

Plasma : a high energy gaseous state of matter.

It is very unstable .

Particles are moving extremely fast, free energy

Most abundant phase of matter

Only present under extremely hot/energetic situations

Example: Sun

Plasma : a high energy gaseous state of matter. It is very unstable . Particles are moving extremely fast, free energy Most abundant phase of matter Only present under extremely hot/energetic situations Example: Sun Plasma

Plasma : a high energy gaseous state of matter.

It is very unstable .

Particles are moving extremely fast, free energy

Most abundant phase of matter

Only present under extremely hot/energetic situations

Example: Sun

CHANGES IN STATE Melting: Solid to liquid Boiling: Liquid to gas Sublimation: Solid to gas The above three require input of energy Condensation: Gas to liquid Freezing: Liquid to solid Deposition: Gas to solid The above three release energy

Melting: Solid to liquid

Boiling: Liquid to gas

Sublimation: Solid to gas

The above three require input of energy

Condensation: Gas to liquid

Freezing: Liquid to solid

Deposition: Gas to solid

The above three release energy

Law vs. Theory S: Develop a law Law: Summarizes the outcome of several experiments that occur repeatedly and consistently. Example: The spoiled food served at lunch makes people sick with a stomachache. Step 5: Develop a theory Theory: Explanation for why a law exists. Example: It is the bacteria in the spoiled food that makes people ill.

S: Develop a law

Law: Summarizes the outcome of several experiments that occur repeatedly and consistently.

Example: The spoiled food served at lunch makes people sick with a stomachache.

Step 5: Develop a theory

Theory: Explanation for why a law exists.

Example: It is the bacteria in the spoiled food that makes people ill.

ELEMENTS contain only one type of atom building blocks of matter 115 known elements today, 90 which occur naturally Found on periodic table The first letter is always capitalized, the second letter is always lower case Fluorine is F, not f Cobalt is Co, not CO (which is carbon monoxide)

contain only one type of atom

building blocks of matter

115 known elements today, 90 which occur naturally

Found on periodic table

The first letter is always capitalized, the second letter is always lower case

Fluorine is F, not f

Cobalt is Co, not CO (which is carbon monoxide)

Atom the smallest particle making up elements

Drawing an Atom of Carbon minus Atomic # = # of n 0 = # of p + and # of e - Carbon has 6 p + and 6 e - Carbon has 6 n 0 C 12.011 6 Atomic Mass Atomic #

Drawing an Atom of Carbon 6 p + 6 n 0 e - e - e - e - e - e -

Compounds Compounds - 2 or more elements chemically combined to form a new substance with new properties Properties – The way a chemical substance looks and behaves

Properties of Matter

PHYSICAL PROPERTIES Characterize the physical state and physical behavior of a substance Each substance has unique physical properties Examples Sulfur appears as a yellow powder The boiling point of water is 100 o C Carbon monoxide is odorless

Characterize the physical state and physical behavior of a substance

Each substance has unique physical properties

Examples

Sulfur appears as a yellow powder

The boiling point of water is 100 o C

Carbon monoxide is odorless

CHEMICAL PROPERTIES Describe ways pure substances behave when interacting with other pure substances. Examples Iron reacts with oxygen to form rust. Platinum does not react with oxygen at room temperature.

Describe ways pure substances behave when interacting with other pure substances.

Examples

Iron reacts with oxygen to form rust.

Platinum does not react with oxygen at room temperature.

What is a physical change? substance changes state but does not change its chemical composition (it has the same melting point, boiling point, chemical composition, etc.) Examples: water freezing into ice cutting a piece of wood into smaller pieces

substance changes state but does not change its chemical composition

(it has the same melting point, boiling point, chemical composition, etc.)

Examples:

water freezing into ice

cutting a piece of wood into smaller pieces

Melting point Boiling point Vapor pressure Color State of matter Density Electrical conductivity Solubility Adsorption to a surface Hardness Characteristics of Physical Changes

Melting point

Boiling point

Vapor pressure

Color

State of matter

Density

Electrical conductivity

Solubility

Adsorption to a surface

Hardness

Reaction with acids Reaction with bases Reaction with other elements Decomposition into simpler substances Corrosion Characteristics of Chemical Changes

Reaction with acids

Reaction with bases

Reaction with other elements

Decomposition into simpler substances

Corrosion

What are chemical changes? when a substance changes into something new. This occurs due to heating, chemical reaction, etc. You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).

when a substance changes into something new.

This occurs due to heating, chemical reaction, etc.

You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).

Review Mixtures and Pure Substances A mixture has unlike parts and a composition that varies from sample to sample A heterogeneous mixture has physically distinct parts with different properties. A homogeneous mixture is the same throughout the sample Pure substances are substances with a fixed composition

Review

Mixtures and Pure Substances

A mixture has unlike parts and a composition that varies from sample to sample

A heterogeneous mixture has physically distinct parts with different properties.

A homogeneous mixture is the same throughout the sample

Pure substances are substances with a fixed composition

A physical change is a change that does not alter the identity of the matter. A chemical change is a change that does alter the identity of the matter. A compound is a pure substance that can be decomposed by a chemical change into simpler substances with a fixed mass ratio An element is a pure substance which cannot be broken down into anything simpler by either physical or chemical means.

A physical change is a change that does not alter the identity of the matter.

A chemical change is a change that does alter the identity of the matter.

A compound is a pure substance that can be decomposed by a chemical change into simpler substances with a fixed mass ratio

An element is a pure substance which cannot be broken down into anything simpler by either physical or chemical means.