Classifying Matter
What is an element?
pure substances that contain only one type of atom
What is a solution?
A liquid mixture that is homogenous on the microscopic level
What is a physical property?
properties that can be determined without changing the nature or identity of a substance
What is a physical change?
Physical Changes are changes in which the identity of a substance doesn’t change
What is the Law of Conservation of Mass?
states that the mass of the reactants equals the mass of the products in a reaction
What is a compound?
pure substances made from one type of molecule, which is made up of multiple elements bonded together
What is a suspension? Give an example
temporary heterogenous mixtures that spontaneously separate over time
Ex. snow globe, muddy water, orange juice, etc
Name 3 physical properties of a piece of paper
White, Thin, Light, Smooth, Bendable, Not dense, cannot dissolve, etc
Name 3 physical changes you can do to a piece of iron
cut it, bend it, melt it, etc
In photosynthesis, plants turn carbon dioxide and water into sugar and oxygen gas.
If a plant starts with 65 grams of carbon dioxide and 45 grams of water, and the plant produces 90 grams of sugar, how many grams of oxygen gas did it make?
65 + 45 = 110
110 - 90 = 20 grams of oxygen
What is a mixture?
contains two or more pure substances mixed together
Give an example of solution. Make sure to name the solute and solvent in your solution example
Ex. Saltwater is the solution
Solute = salt
Solvent = water
What is a chemical property?
Chemical properties describe how substances can react with other matter and can only be observed by changing the identity of a substance
What is a chemical change?
changes that transform one or more chemicals into new substances
What is physical weathering? give an example
when physical changes help break down rocks
Ex. water, wind, ice, rain
Name and define the two types of mixtures
Homogenous mixtures are mixtures where the pure substances are distributed uniformly throughout and the different pure substances cannot be seen
Heterogenous mixtures are not evenly mixed and clearly show the different substances
What is a colloid? Give an example
A mixture that appears homogenous to the naked eye, but is actually made of heterogeneous particles under the microscope
Ex. blood, milk
Name 3 chemical properties of a piece of paper
Flammable, doesn't react with water, doesn't react with oxygen, etc
Name at least 1 chemical change you can do to a piece of iron
rust it, react it with acid, corrode it with a base, etc
What is chemical weathering? give an example.
when chemical changes help break down rocks
ex. acid rain, rusting, acid in plant roots, etc
Explain at least 3 differences between mixtures and compounds
Mixtures are mixed together while compounds are bonded together
Compounds have the same composition throughout, while mixtures may vary
Compounds have the same properties throughout, while mixtures may vary
Mixtures can be more easily separated through physical reactions while compounds must be separated through chemical reactions
What can we do to determine if a liquid mixture is a solution or colloid? What is this effect called?
You can identify whether a liquid is a colloid by passing a beam of light through it
A light beam will be invisible passing through a solution because the particles are too small
But when it passes through a colloid, the particles are big enough to scatter the light beam in a process called the Tyndall effect
Tell me whether the following properties or chemical or physical:
flammable
magnetic
conductive to electricity
high density
rusting
flammable - chemical
magnetic - physical
conductive to electricity - physical
high density - physical
rusting - chemical
What are the 4 signs of a chemical change?
Production of a gas
Change in color
Energy change
Production of a precipitate
What is a precipitate?
a solid that forms when mixing multiple liquids or gases