PHYSICAL AND CHEMICAL CHANGES

Vocabulary #41. Force- A push or a pull.2. Electrical Force- The force between two charged

objects.3. Magnetic force- the force of attraction or

repulsion between magnetic poles.4. Gravitational force- a force that pulls objects

toward each other (gravity).5. Mass- the measure of the amount of matter in an

object, is measured in grams!!!!6. Net force- the combination of all the forces

acting on an object.7. Cryosphere- the sphere of the Earth that

contains all the ice (glaciers)8. Atmosphere- the sphere of the Earth that

contains all gases

9. Hydrosphere- the sphere of the Earth that contains all water such as oceans, lakes, rivers.

10. Atomic Number- The number of protons in the nucleus of an atom.

11. Boiling point- the temperature at which a substance boils.12. electrical conductivity- the ability of an object to carry

electric current.13. magnetism- the ability of an object to be attracted to a

magnetic field.14. Melting point- the temperature at which a substance

melts.15. Thermal conductivity- the ability of an object or substance

to conduct (transfer) heat.

PHYSICAL CHANGE

PHYSICAL CHANGE When the

appearance or form of a substance is changed but no new substance is produced.

PHYSICAL CHANGES

As you know, matter occurs in three states – solid, liquid, and gas. A puddle of liquid water left in the sun will not be there in two hours. The water won’t disappear but a physical change will happen. The liquid water changes into water vapor, a gas. When the appearance or form of a substance has changed but no new substance is produced, the matter has undergone a physical change. All changes in the state of matter of a substance are physical changes. Other examples of physical changes are bending, crushing, breaking, and dissolving. The methods of separating mixtures, such as filtration and distillation, also involve physical changes.

PHYSICAL CHANGES

Changes in the state of matter of a substance are physical changes.

OTHER PHYSICAL CHANGES

BENDING

OTHER PHYSICAL CHANGES

Crushing

OTHER PHYSICAL CHANGES

Breaking

OTHER PHYSICAL CHANGES

Dissolving

CHEMICAL CHANGE

A change in matter that produces one or more new substances is called a chemical change or chemical reaction.

CHEMICAL CHANGE

A change in matter that produces one or more new substances is a chemical change, or chemical reaction. In some chemical changes, a substance breaks down into two or more other substances. For example, hydrogen peroxide breaks down into water and oxygen gas when it’s poured on a cut on your skin. In other chemical changes, two or more substances combine to form different substances.

CHEMICAL CHANGEPHOTOSYNTHESIS

Everything you encounter is made up of some combination of a finite set of elements. Atoms from two or more of these elements can combine in many ways. Photosynthesis is a chemical change that happens naturally in plants. Several compounds combine using energy from the sun to produce new compounds. All living and nonliving things are made up of substances that formed through a wide variety of chemical changes of the elements.

EXAMPLES OF CHEMICAL CHANGES

COMBUSTION – the rapid combination of a fuel with oxygen.

Combustion produces heat, light, and new substances

Example: gas, oil, or coal burning in a furnace.

EXAMPLES OF CHEMICAL CHANGES

Electrolysis – the use of electricity to break a compound into elements or simpler compounds

Example – the use of electricity to break water down into hydrogen and oxygen.

EXAMPLES OF CHEMICAL CHANGES

Oxidation – the combination of a substance with oxygen.

Example – the rusting of iron

How do I know if a change is chemical or physical?

There are clues we can use to let us know if a chemical change has taken place……

#1 Change of color

Chemical changes often involve a change of color

#2 Change in Temperature

Chemical reactions often give off or absorb heat.

#3 Changing Form

Chemical reactions often involve a change in the form of the material.

#4 Release of light, heat, or sound

#5 Formation of gases

Chemical reactions often involve the release of gases (bubbles)

#6 Form of precipitate

Chemical reactions often involve the formation of a precipitate.

#7 Decomposition of Organic Matter

The decomposition of organic matter is a chemical reaction