Elements, compounds, mixtures & Moles

Question 1

What is relative atomic mass?

Answer 1

Ar = mass of element

Question 2

What is relative formula mass?

Answer 2

Mr = mass of substance

Question 3

How to calculate Mr?

Answer 3

Add all Ar from all elements in mixture.

Question 4

What is empirical formula?

Answer 4

Simplified chemical formula to smallest whole number ratio.

Question 5

What’s a balanced chemical equation?

Answer 5

Shows reaction, same number of atoms and mass in both sides.

Question 6

What’s a pure substance?

Answer 6

Substance that consist of only one element?

Question 7

How does melting point determine if it’s pure or not?

Answer 7

Melting point is lower, and melting in range of temperature means it’s IMPURE.

Question 8

What’s a solution?

Answer 8

A substance that has dissolved in another.

Question 9

Different components of the solution?

Answer 9

Solute: Substance which dissolves
Solvent: Where the solute dissolved in

Question 10

What’s filtration?

Answer 10

Separates, insoluble substance form solution.

Question 11

What’s simple distillation?

Answer 11

Boils lower melting point substance first, leaving other behind.

Question 12

How does fractional distillation work?

Answer 12

Separates 2 or more substances from mixture in liquid state (each substance has different boiling point).

Question 13

How does chromatography work?

Answer 13

Mobile phase moves through stationary phase, separates coloured substance.

Question 14

What’s a period (periodic table)?

Answer 14

Horizontal row

Question 15

What’s a group (periodic table)?

Answer 15

Vertical column

Question 16

What’s an ion?

Answer 16

A charged particle, molecule or atom.

Question 17

What’s ionic bonding?

Answer 17

One electron goes to other substance. Linking them ionically. (Non-metal = Metal)

Question 18

What’s covalent bonding?

Answer 18

Shared pair of electrons. (Non-Metal - Non-Metal)

Question 19

What’re polymers?

Answer 19

Group of smaller monomers (monomers) joined together (linked up).

Question 20

What’re metallic bonds?

Answer 20

Metals loose electrons forming sea of electrons which keep all metal ions together.

Question 21

Why some substances conduct electricity?

Answer 21

Because they have free electrons that can move.

Question 22

How big are nano particles?

Answer 22

1-100 nm (nanometers)

Question 23

How do you write the formulae of metal elements?

Answer 23

Always in the empirical formula, because they’re in giant latices.

Question 24

What is conservation of mass?

Answer 24

Mass is never gained or lost in a chemical reaction (closed system).

Question 25

What are state symbols?

Answer 25

They show the physical state of substances in chemical reactions.

Question 26

What’re half equations?

Answer 26

Half equations show the change of one reactant in a reaction (include charges).

Question 27

What’re ionic equations?

Answer 27

Shows ion presents in a reaction mixture.

Question 28

What’s a mole?

Answer 28

Is the unit for amount of substance.

Question 29

What is 1 mole?

Answer 29

1 mole = number of particles in 12g of Carbon-12. (6.02 x 10^23)

Question 30

What is 1 mole equal to?

Answer 30

1 mole = Ar (or Mr)

Question 31

What is the equation relating mass, Mr, and moles.

Answer 31

mass = Mr x mol