Objective 3—Structues and Properties of Matter

Matter: anything that has mass and takes up space; makes up all things living and nonliving in the world; classified by properties, or characteristics, including:

Property          Description (measured in)

State                  form of matter – solid, liquid, or gas

Mass                  amount of matter in an object (grams)

Weight               amount of gravity on an object (Newtons)

Volume                         amount of space an object takes up (liters)

Density                          mass divided by volume (grams / liter)

Magnetism       ability to be attracted or pulled to magnets

Conduction       ability to carry heat, electricity, and sound (the opposite of conduction is insulation)

Boiling Point    from liquid to gas for water 100°C (°C)

Freezing Point  from liquid to solid for water 0°C (°C)

Atoms: are the very small substances (building blocks) of all matter.  The nucleus is the central part of the atom and contains most of its mass.  An atom has 3 subatomic particles:

Proton: located in the nucleus has a positive (+) charge

Neutron: located in the nucleus has a neutral (o) charge

Electron: located in the electron cloud has a negative (-) charge

Periodic Table: chart of elements arranged in rows in increasing atomic number

Atomic Number: the number of protons in the nucleus of one atom of the element

Group / Family: elements in the periodic table in the same column up and down with similar physical or chemical properties

Period: elements in the periodic table in the same row left to right whose properties change gradually and predictably

Element: substance made of only one kind of atom Ex. carbon, oxygen, iron, hydrogen

Molecule: smallest number of atoms that make up a compound

Compound: substance made of two or more elements

 

Chemical Formula: a substance’s abbreviation Ex. C₆H₁₂O₆

Model of a C₆H₁₂O₆ - glucose (sugar) molecule / compound

Carbon (C) red

Hydrogen (H) is white

Oxygen (O) is green

Metals: located on the left side of the periodic table; have luster – shiny, malleable – can be flattened or shaped, ductile – can be drawn out into wires, good conductors of heat and electricity, most are solid at room temperature

Nonmetals: located on the right side of the periodic table; dull, brittle, poor conductors of heat and electricity, most are gasses at room temperature

Metalloids: located along the zigzag (stair step) line; semiconductors – do not conduct electricity as well as a metal, but conducts it better than a nonmetal

Physical Change: change in size, shape, or state; still the same substance Ex, steam and ice are both still water

Chemical Reaction: process in which one or more substances change to produce a new substance

Reactant: substance that exists before a chemical reaction begins

Product: substance that forms as a result of a chemical reaction

2H₂         + O₂               à    2H₂O

reactant + reactant yields product

Law of Conservation of Mass: mass is not created or destroyed in an ordinary chemical reaction total mass of the reactants = total mass of the products

Exothermic Reaction: gives off or produces energy; Ex. hand warmers - feels warm to the touch

Endothermic Reaction: takes in or absorbs energy; Ex. cold packs – feels cold to the touch

Chemical Symbol: element’s abbreviation; first letter is capitalized and second letter (if there is one) is lowercase Ex. N – Nitrogen, Au – Gold

Specific Heat :

According to the data table water would take the most heat energy to raise the temperature of 1 kg of the substance 1°C; brass would take the least heat energy to raise the temperature of 1 kg of the substance 1°C

Energy can be transformed or changed from one form to another.  People transform energy to meet their needs. The following are examples of energy transformations:

Chemical energy from gasoline is converted to mechanical energy when you drive a car.

Electrical energy is converted to light energy when you turn on a lamp.

Mechanical energy from wind is converted to electrical energy in windmills (wind turbines).

Chemical energy from batteries is converted to sound energy when you turn on a battery powered radio.

 

Mrs. Davis’

8th Grade Science