Physical Science Grade 8 - Final Exam

Name 2 chemical changes that can be done to a piece of paper:

- Burning - Dissolving in Acid

Chemical PE (define) Example:

- Capable of transferring chemical energy. - food, energy drinks, batteries

Batteries (_______________ _________________) are used to turn on a flashlight (________________________ _______________________).

- Chemical Energy - ELECTROMAGNETIC (RADIANT) ENERGY

Fossil fuels (________________ ______________) are burned, which is called combustion, and heat (_________________ _____________________) is released.

- Chemical Energy - Thermal Energy

Natural gas (______________ ____________) heats (_____________ _____________) water.

- Chemical Energy - Thermal Energy

In a series circuit: Adding another bulb will cause the other bulbs to get DIMMER / BRIGHTER because ____________________________________________________

- DIMMER - the light bulbs have to share the energy from the power source

A microwave (___________________________ _______________________/_____________________ _____________________) in a house turns on because of energy produced in a nuclear power plant from an atom's nucleus (_____________________ ____________________).

- ELECTRICAL ENERGY/ELECTROMAGNETIC (RADIANT) ENERGY - Nuclear Energy

A light bulb [visible light] (_________________________ __________________) turns on because of turning on the light switch (___________________ ______________).

- ELECTROMAGNETIC (RADIANT) ENERGY - Mechanical Energy

When does an object possess kinetic energy? Example:

- Energy in motion. - A person riding a bike down a hill

Heat always moves from a HOTTER / COLDER object to a HOTTER / COLDER object.

- HOTTER - COLDER

What does it mean if something has potential energy? Example:

- It is capable of doing work or causing change. - Roller coaster at the top of a hill

In Kool-Aid, the solute is the ___________________________ and the solvent is the ___________.

- Kool-Aid powder - Water

The region around the magnet is known as the ___________________________. The closer these lines are together, __________________________________________.

- Magnetic Field - the stronger the magnetic field

A spinning turbine (___________________ _______________) produces usable energy to power homes (____________________ ____________________).

- Mechanical Energy - Electrical Energy

You rub your hands together (________________________ __________________) on a cold day, and friction is created to produce heat (______________ _______________).

- Mechanical Energy - Thermal Energy

Similar charges ATTRACT / REPEL, while opposite charges ATTRACT / REPEL.

- REPEL - ATTRACT

Give an example of an: Insulator ______________ Conductor ______________

- Wood - Copper

Looking at the Periodic Table, describe what an element is and identify an example of an element.

- an element is a single atom - an example would be hydrogen

Name 3 properties that would describe salt.

- color - shape - solubility

Describe chemical properties.

- irreversible - bonds are broken - new bond is formed creating a new substance

An electron has a _______________ charge and is located in the _________________________.

- negative - electron cloud/orbital

A neutron has a ______________ charge and is located in the ______________________.

- neutral - nucleus

A nucleus has a ________________ charge and is located in the ________________ __ _________________.

- positive - center of atom

A proton has a _________________ charge and is located in the ______________.

- positive - nucleus

Describe physical properties.

- reversible - observed by the senses - change occurs and no new substance is formed

H2O is the molecular formula for __________________. The 2 means __________________________; no number after the O indicates _____________________________.

- water - 2 hydrogen atoms - 1 atom of oxygen

Acidic solutions→ pH levels from _____ to _____, with the strongest acids having a pH of _____.

1 6 1

List the 5 elements that make up the DNA macromolecule:

1). CARBON 2). HYDROGEN 3). OXYGEN 4). NITROGEN 5). PHOSPHOROUS

Identify evidence that a chemical change has occurred:

1. Color Change 2. pH Change 3. Release of Light 4. Temperature Change 5. Formation of Precipitate 6. Formation of Bubbles 7. Change in Smell

Describe 3 physical changes that can be done to a piece of paper.

1. Cutting 2. Crumpling 3. Folding

A neutral substance has a pH of _____.

7

Basic solutions→ pH levels from _____ to _____, with the strongest bases having a pH of _____.

8 14 14

CHEMICAL CHANGE (define)

A change that occurs to a substance that breaks bonds and produces new substances.

PHYSICAL CHANGE (define)

A change that occurs to a substance without actually changing its chemical makeup.

Describe the difference between heterogeneous and homogeneous mixtures:

A heterogeneous mixture is unevenly mixed and you may see individual parts in the mixture. A homogeneous mixture is evenly mixed and the individual parts can no longer be identified.

Describe what makes DNA a "macromolecule."

A large molecule made up of thousands of atoms

What is the difference between an INSULATOR and a CONDUCTOR?

An insulator is a material that does not allow electrons to flow freely through it (Ex: rubber, wood, yarn, plastic) A conductor is a material that allows for electrons to flow freely through it (Ex: Steel, Iron, Copper)

List the types of atoms and how many of each would be found within the compound Vinegar (C2H4O2)

Atom #1: CARBON; There are 2 of them Atom #2: HYDROGEN; There are 4 of them Atom #3: OXYGEN; There are 2 of them

BALANCED or UNBALANCED ____ N2 + _3_ H2 → _2_ NH3

BALANCED

A CHEMICAL / PHYSICAL change occurs when bonds are broken.

CHEMICAL

Solvent (define)

Does the dissolving.

TRUE / FALSE Typically there is more solute than solvent in a solution.

FALSE

TRUE / FALSE. Most forms of energy cannot be converted into other forms.

FALSE

TRUE / FALSE. Only nuclear energy is produced in a nuclear reaction, not light or heat.

FALSE

TRUE / FALSE: Elements maintain their same physical and chemical properties when they bond to form new compounds.

FALSE

What is the difference between HEAT and TEMPERATURE?

Heat: The transfer of thermal energy from a hot object to a cold object.

Describe what magnetism will help you to separate.

Helps separate magnetic substances.

Describe dissolving will help you to separate.

Helps separate substances that can be dissolved in a solvent and those that cannot apart

Solubility (define)

How much of the solute will dissolve within the solvent.

Solute (define)

Is dissolved

Electric currents always flow from (-) to (+) taking the path of MOST / LEAST resistance.

LEAST

Identify an example of a homogeneous mixture:

Milk, Cake Batter, Plain Yogurt

Non-Renewable or Renewable: Coal

Non-renewable

Non-Renewable or Renewable: Nuclear

Non-renewable

Non-Renewable or Renewable: Petroleum

Non-renewable

What is the difference between nuclear fusion and nuclear fission?

Nuclear fusion: Energy is released when nuclei fuses together Nuclear fission: Energy is released when the atom's nucleus is split.

SERIES / PARALLEL circuits have more than one pathway for the electrons to flow through.

PARALLEL

A CHEMICAL / PHYSICAL change occurs when no new substance is formed.

PHYSICAL

Magnetism is a PHYSICAL / CHEMICAL property.

PHYSICAL

Which circuit will have the brightest bulbs?

Parallel circuit

Non-Renewable or Renewable: Biomass

Renewable

Non-Renewable or Renewable: Geothermal

Renewable

Non-Renewable or Renewable: Hydroelectric

Renewable

Non-Renewable or Renewable: Solar

Renewable

Non-Renewable or Renewable: Wind

Renewable

SERIES / PARALLEL circuits have one pathway for electrons to flow through.

SERIES

Identify an example of a heterogeneous mixture:

Salad, Snickers, Parfait

Describe evaporation will help you to separate.

Separates a dissolved SOLUTE from a SOLUTION.

Describe filtration will help you to separate.

Separates substances with different size particles.

Which circuit has the dimmest bulbs?

Series circuit

TRUE / FALSE Solutes and solvents can be solids, liquids, or gases.

TRUE

TRUE / FALSE When a salt dissolves in water, each of its particles is surrounded by water molecules. This is why the freezing point of salt water is lower than the freezing point of fresh water.

TRUE

TRUE / FALSE. A magnet is capable of producing an electric current.

TRUE

TRUE / FALSE. All things, living and nonliving are made up of atoms.

TRUE

TRUE / FALSE. Every chemical reaction involves a change in energy.

TRUE

TRUE / FALSE. Fusion releases 3-4 times more energy than fission.

TRUE

TRUE / FALSE. In a parallel circuit, the current from each bulb has its own path.

TRUE

Energy (define)

The ability to do work or cause change

In a series circuit: Removing one of the bulbs will cause the others to... ____________________

Turn Off

BALANCED or UNBALANCED ___2 K + ____ Cl2 → __2 KCl

UNBALANCED

BALANCED or UNBALANCED ____ P4 + ___3 O2 → 2 P2O3

UNBALANCED

Energy stored in ________________________________.

an atom's nucleus

Describe how the modern Periodic Table of elements is organized.

atomic number

A chemical change that absorbs energy is called an ___________________ reaction.

endothermic

The Law of Conservation of Energy states that when one form of energy is converted into another, ____________________________________________________________________________________________

energy cannot be created or destroyed - only transformed from one form to another.

A chemical change that gives off energy is called an __________________ reaction.

exothermic

What gives an object magnetic properties?

magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other materials, such as iron, and attracts or repels other magnets.

Describe the Law of Conservation of Matter.

matter cannot be created nor destroyed, but can only be converted from one form to another

Atoms are so small that many scientists throughout history have created _____________________ to describe them.

models

Describe the difference between a molecule and a compound.

molecule: forms when two or more atoms join together compound: is a molecule that includes two different elements

A ___________ turns a circuit on and off by opening or closing.

switch

Name a property that would identify salt.

taste

Why have atomic theories changed over time?

the advancement of new technology