Principles of Chemistry

Question 1

Define atom

Answer 1

the smallest particle of an element that can exist and still retain the properties of that element

Question 2

Define molecule

Answer 2

a group of two or more atoms bonded together

Question 3

What 3 subatomic particles make up the atom

Answer 3

Proton
Neutron
Electron

Question 4

What is the nucleus of an atom

Answer 4

the small, dense centre of an atom that contains protons and neutrons

Question 5

What is the atomic number (chem)

Answer 5

The number of protons in an atom

Question 6

What is the mass number (chem)

Answer 6

The total number of protons and neutrons in an atom

Question 7

What is an isotope

Answer 7

Isotopes are different atomic forms of the same element which have the same number of protons but different numbers of neutrons

Question 8

What is relative atomic mass (Aᵣ)

Answer 8

The weighted average mass of the isotopes of an element compared to 1/12 the mass of a carbon-12 atom

Question 9

How are elements arranged in the periodic table

Answer 9

Order of atomic number
Groups/Periods

Question 10

Do metals conduct electricity?

Answer 10

Yes
Delocalised electrons

Question 11

Do non-metals conduct electricity?

Answer 11

No
Lack free electrons (apart from graphite)

Question 12

What type of oxides do metals form?

Answer 12

Basic oxides

Question 13

What type of oxides do non-metals form?

Answer 13

Acidic oxides

Question 14

Covalent bonding definition

Answer 14

Strong electrostatic forces of attraction between common nuclei and a shared pair of electrons

Question 15

Why do substances with simple molecular structures have low melting and boiling points?

Answer 15

Intermolecular forces between molecules are weak
Little energy to overcome

Question 16

Intermolecular forces in simple molecular structures increase as what increases?

Answer 16

Mᵣ
Relative molecular mass

Question 17

What state are most molecular substances at RTP?

Answer 17

Liquid/Gas

Question 18

Why do intermolecular forces in simple molecular structures increase with Mᵣ?

Answer 18

As Mᵣ increases
Molecules are larger
Surface area increases
More points of contact between molecules

Question 19

Why do substances with giant covalent structures have high melting/boiling points?

Answer 19

It requires lots of energy to break the strong covalent bonds between atoms

Question 20

Describe the structure of diamond

Answer 20

Each carbon atom forms 4 covalent bonds

Question 21

Why is diamond so hard

Answer 21

The strong covalent bonds hold the atoms in a very rigid lattice structure

Question 22

Why doesn’t diamond conduct electricity?

Answer 22

No free electrons/ions

Question 23

Describe the structure of graphite

Answer 23

Each carbon atom forms 3 covalent bonds
Layers of carbon atoms held together weakly by intermolecular forces
Layers are free to slide over each other

Question 24

Why does graphite conduct electricity?

Answer 24

Each carbon atom has 1 delocalised electron

Question 25

Are giant covalent structures soluble in water?

Answer 25

No

Question 26

Describe the structure of C₆₀ Fullerene

Answer 26

Hollow spheres made up of 60 carbon atoms

Question 27

Is C₆₀ Fullerene giant covalent?

Answer 27

No

Question 28

Why is C₆₀ Fullerene soft?

Answer 28

C₆₀ molecules are only held together by intermolecular forces so they can slide over each other

Question 29

Why is C₆₀ Fullerene a poor conductor of electricity?

Answer 29

Each carbon atom in C₆₀ has 1 delocalised electron but they can't move between molecules

Question 30

Do covalent compounds usually conduct electricity?

Answer 30

No

Question 31

Definition of ionic bonding

Answer 31

Strong electrostatic forces of attraction between 2 oppositely charged ions

Question 32

Define ion

Answer 32

An electrically charged atom or group of atoms by the loss/gain of electrons

Question 33

What is a cation

Answer 33

Positive ion

Question 34

What is an anion

Answer 34

Negative ion

Question 35

What type of ions do metals form

Answer 35

Cation

Question 36

What type of ions do non-metals form?

Answer 36

Anion

Question 37

Why do compounds with giant ionic lattices have high melting/boiling points?

Answer 37

The strong electrostatic forces between oppositely charged ions in the giant lattice require a lot of energy to overcome and break apart

Question 38

Can ionic compounds conduct electricity when solid?

Answer 38

No

Question 39

When can ionic compounds conduct electricity and why?

Answer 39

Molten/Dissolved The ions are free to move and carry charge

Question 40

What is metallic bonding?

Answer 40

The strong electrostatic forces of attraction between positive metal ions and the sea of delocalised electrons

Question 41

What is a valence electron

Answer 41

The electrons in the outer shell of an atom

Question 42

Why do metals have high melting/boiling points?

Answer 42

Many strong metallic bonds in giant metallic structures Lots of energy required to overcome

Question 43

Why do metals conduct electricity?

Answer 43

Free electrons are able to move and carry charge

Question 44

Why are metals malleable and ductile

Answer 44

Layers of positive ions can slide over one another (regular structure) Bonding is not disrupted

Question 45

Why do metals conduct heat?

Answer 45

Delocalised electrons transfer heat energy Ions in the lattice vibrate in place, passing energy to neighbouring ions

Question 46

What is an alloy?

Answer 46

An alloy is a mixture of two or more elements, with at least one metal

Question 47

Why are most alloys harder than pure metals?

Answer 47

Regular lattice disrupted by different sized atoms Harder for layers to slide

Question 48

What is a mole (mol)

Answer 48

A mole is a unit used to measure the amount of substance. It represents 6.02 × 10²³ particles

Question 49

What is empirical formula?

Answer 49

The empirical formula is the simplest whole number ratio of atoms of each element in a compound

Question 50

What is molecular formula?

Answer 50

The molecular formula shows the actual number of atoms of each element in a molecule

Question 51

What is the formula n = c × V used for?

Answer 51

It’s used to calculate the number of moles (n) of a solute in a solution c is concentration (mol/dm³) V is volume (dm³)

Question 52

Mass = ? (chemistry moles calcs)

Answer 52

m = Mᵣ × Moles

Question 53

Percentage yield = ?

Answer 53

actual yield / theoretical yield

Question 54

v = ? (At RTP) (Chem)

Answer 54

v = 24n

Question 55

How do you convert between dm³ and cm³

Answer 55

1 dm³ = 1000 cm³