Chapter 1K & 2K Study guide
Test is ___________________________
Use this study guide, your notes, labs and handouts to study!
Know the definitions of the following terms and the units that we use to measure them.
Mass: the amount of matter in an object; grams and kilograms
Volume: the amount of space that an object takes up; mL and cm³
Density: the ratio of mass to volume in an object; D= mass ÷ volume; g/mL and g/cm³
Determine the density of a candy bar if the candy bar has a volume of 4 cm³ and a mass of 9 grams.
Show your work.
D=m/v=9grams÷4cm³=2.25 g/cm³
Would the candy bar float or sink in a tub of water. Explain.
The candy bar would float in a tub of water because it’s density is greater than water’s density which
is 1g/cm³
If you take a beaker with 35 grams of water and you freeze it, how many grams of ice will you have?
Explain.
You will have 35 grams of water. Grams is a measure of mass. Mass of an object does not change
unless you make it smaller or bigger. The amount of water is not changing so the mass stays the same.
What are the 3 States of matter? Define each and give an example of each.
1. Solid: definite mass and definite volume; molecules are packed tightly together and vibrate in
place
Examples: desk, pencil, book
2. Liquid: definite volume but not a definite shape; liquids take the shape of the container they are in
Examples: milk, water, gatorade
3. Gas: no definite shape or volume; gases take the shape and volume of the container they are in
Examples: air, carbon dioxide, helium
Define:
Freezing point: the temperature at which a substance changes from a liquid to a solid
Of Water: 0°C
Melting point: the temperature at which a substance changes from a solid to a liquid
Boiling point: the temperature at which a substance turns from a liquid to a gas when heat is applied
Solution: one substance is dissolved in another substance; a well-mixed mixture (ex: mixing kool-aid
powder, sugar & water)
Mixture: two or more substances are mixed together but are not chemically combined(ex: chex mix)
Atom: smallest particle of an element; cannot be broken down into smaller pieces
Element: a substance that cannot be broken down into other substances; made of one type of atom
Compound: substance made of two or more elements that are chemically combined
Pure Substance: substance made of only one kind of matter and having definite properties (ex salt,
sugar)
Law of Conservation of Matter: matter cannot be created or destroyed; it just changes form (ex: a
log burning to ash and smoke, still the same amount of matter but in a different form)
Chemical Bond: the force that holds two atoms together
Physical Property: characteristics of matter that we can determine by using our five senses (ex: color,
taste etc)
Chemical Property: characteristics you cannot identify just by looking at a substance; you must do a
chemical test or experiment to determine chemical properties (ex: reacting with other substances)
What is a physical change? Give 2 examples of physical changes.
Can change the appearance of a substance but does not change into a new substance; can you get it
back to what it was originally? Then it is probably a physical change.
Examples: cutting paper, crushing a can
What is a chemical change? Give 2 examples of chemical changes.
A new substance is formed; cannot get it back to what it originally was
Examples: burning wood, iron rusting
Think back to our lab where we put aluminum in a copper chloride solution. After the chemical change,
did we have more, less or the same amount of aluminum? Explain. (Hint: Matter CANNOT be
created or destroyed!-think about wood burning to help you)
The same amount of aluminum; a chemical change took place but matter was not created or destroyed-it
changed form; the aluminum foil rusted, created heat and turned into a gas.
What is the density of water? 1.0 g/mL or 1.0g/cm³
Be able to calculate the density of two items and determine which one has a higher or lower density.
Ex: Two boxes have a volume of 7 cm³. Box 1 has a mass of 14 g and Box 2 has a mass of 21 g.
Calculate the densities of both boxes. Which box has a higher density? Show your work.
D=mass÷volume
Box 1: 14g ÷ 7cm³ = 2g/cm³
Box 2: 21g ÷ 7cm³ = 3g/cm³
Box 2 has a higher density
Explain the difference between atoms and molecules.
Atoms are the smallest particles of an element. Atoms can combine with other atoms to form
molecules.
A molecule is a group of atoms that are joined together and act as a single unit.