Topic 1 - Key Concepts

Question 1

Ammonia formula

Answer 1

NH3

Question 2

Ammonium ions formula

Answer 2

NH4+

Question 3

Nitrate formula

Answer 3

NO3-

Question 4

Sulfate formula

Answer 4

SO4 2-

Question 5

Hydroxide formula

Answer 5

OH-

Question 6

Carbonate formula

Answer 6

CO3 2-

Question 7

Ionic equation

Answer 7

If a substance is ionic and aq, then it can be split into its individual ions to get he equation.

Question 8

Atom models

Answer 8

Dalton model - solid spheres, JJ Thompson - Electrons inside sphere(plum pudding model), Rutherford - Positive nucleus, electrons float, Bohr - electron shells

Question 9

Nucleus size and mass

Answer 9

Tiny compared to rest of atom but most of the mass in the atom is inside it

Question 10

Mass number

Answer 10

Total number of protons and neutrons in an atom

Question 11

Atomic number

Answer 11

Proton amount. Amount of protons is unique to each atom.

Question 12

Isotope

Answer 12

An atom with the same number of protons but a differetn number of neutrons in the nucleus. There are different isotopes for some different elements, which leads to their mass numbers not being whole.

Question 13

Relative atomic mass calculation based on isotopic abundances

Answer 13

Multiply each isotope mass by its quantity. Then add all of them upp and divide by the sum of the quantities.

Question 14

How did mendeleev arrange his table

Answer 14

Based on atomic mass which put elements with similar properties in columns. Some were wrong due to isotopes, and gaps were left for undiscovered elements, which he predicted the properties of.

Question 15

Periodic table arrangement now

Answer 15

Ascending atomic number, rows called periods which represent shells on the atom, columns called groups which have elements with similar properties

Question 16

Ionic bonding

Answer 16

When a metal and non-metal bond by the metal losing electrons and giving them to the non-metal. The oppositely charged ions are strongly attracted to eachother by electrostatic forces.

Question 17

Ionic compounds properties

Answer 17

Lattice structure, high melting and boiling points, delocalised electrons so can carry electric charge

Question 18

Covalent bonding

Answer 18

When a pair of electrons is shared between two atoms. Leads to formation of molecules( around 10 power -10 m size)

Question 19

Giant covalent structures

Answer 19

Large molecules held by strong covalent bonds. High boiling and melting points. Dont conduct electricity. Eg diamonds, graphite, graphene(all forms of carbon)

Question 20

Metallic bonding

Answer 20

Giant structures held very strongly together by electrostatic attraction between positive metal ions and electrons.

Question 21

Graphite

Answer 21

Three covalent bonds creating sheets of carbon atoms
arranged in hexagons. The sheets slide over eachother meaning it is soft and slippery. Used for lubricants

Question 22

Diamond

Answer 22

Network of carbon atoms that from 4 covalent bonds. Rigid lattci structure leads to it being really hard. Used to strengthen cutting tools

Question 23

Fullerenes

Answer 23

Molecules of carbon in closed tubes or hollow balls.

Question 24

Buckminsterfullerene

Answer 24

C60. Forms a hollow sphere made of 20 hexagons and 12 pentagons. Stable molecule that forms soft crystals.

Question 25

Metal properties

Answer 25

Mostly very high melting and boiling points. In pure metals, layers of atoms can slide over eachother, making metals malleable. Good conductors.

Question 26

relative formula mass Mr =

Answer 26

All the atoms relative atomic masses in the formula

Question 27

What is empirical formula

Answer 27

The simplest ratio of atoms

Question 28

Law of consrvation of mass

Answer 28

No atoms are created or destroyed . In a closed system, the mass will stay the same

Question 29

What leads to the mass increasing during a reaction

Answer 29

The reactant is a gas in the air, so it is used by the reaction and more atoms are present in the product.

Question 30

What leads to mass decreasing during a reaction

Answer 30

When the product is a gas, it is released to the air and therefore the product has less atoms than the original reactants.

Question 31

Concentration unit

Answer 31

g dm-3

Question 32

Concentration =

Answer 32

Mass of solute / Volume of solution

Question 33

Avogadros constant shows

Answer 33

The amount of atoms in a mole

Question 34

Avogadros constant =

Answer 34

6.02 x 10^23

Question 35

Moles =

Answer 35

Mass(g) / Mr

Question 36

Particles of a substance =

Answer 36

Moles x 6.02 x 10^23

Question 37

How is the magnesium oxide experiment carried out to find empirical formula

Answer 37

Weight magnesium. Heat it in a crucible whilst letting oxygen in until it turns white Weigh the magnesium oxide Use the masses and Mr of magnesium and oxygen to find the empirical formula

Question 38

Reactions stop when

Answer 38

The limiting reactant is used up

Question 39

The amount of product formed is directionally proportional to

Answer 39

The amount of limiting reactant

Question 40

How to find the balanced symbol equation of a reaction using the masses of the substances

Answer 40

Find moles of each substance using mass/Mr. Divide each number of moles by the smallest number of moles in a single substance. Make all the numbers whole and write them before each substance.