Pure Substance vs. Mechanical Mixture vs. Solution/ Elements vs. Compounds

Question 1

What is the definition of a Pure Substance?

Answer 1

A pure substance is only made up of ONE type of particle

Distilled water is pure because it only contains water particles, tap water isn’t cure because it contains fouride, chlorine, etc.

Question 2

What can pure substances be classified as?

Answer 2

Elements or compounds

Question 3

What is an element?

Answer 3

A pure substance that can’t be broken apart

EX: Oxygen is an element (O)

Question 4

What is a compound?

Answer 4

A pure substance that can be broken down. It’s made up of two or more types of atoms that are chemically combined. EX: H2O is made of hydrogen and oxygen

Question 5

What is an atom?

Answer 5

An the smallest particle in matter, also indivisible

Question 6

What is a molecule?

Answer 6

When atoms are combined they form molecules

Question 7

What is a Mechanical Mixture?

Answer 7

When two or more pure substances are mixed together, thus being made up of more than one type of particle.

You can also see the that it’s a mixture and that there’s more than one part. EX: Chocolate chip cookie

Question 8

What is a Solution?

Answer 8

Two or more pure substances but you can only see one phase, one particle is dissolved in another.

You can only see one part of it. EX: Sugar dissolves in tea

Question 9

Why and how do compounds form? Think back to Bohr-Rutherford diagrams

Answer 9

Compounds form when there is space in their “outer shell”. Elements like Helium which has a full outer shell w/ two electrons do not form compounds. But Hydrogen (one electron) and Florine (9 electrons) will. Hydrogen’s 1 electron will make a complete outer shell for Florine.

Question 10

How many atoms are in the chemical formula Na2CO3?

Answer 10

Na = 2 atoms Carbon = 1 atom Oxygen = 3 atoms

Question 11

How many atoms are in the chemical formula H2O?

Answer 11

H = 2 atoms Oxygen = 1 atom