Unit 1 Part 1

Question 1

What is the difference between a physical and chemical change?

Answer 1

Physical changes are usually reversible (eg: changes of state).

Chemical changes are usually permanent and always produce a new substance.

Question 2

Define Exothermic

Define Endothermic

Answer 2

Exothermic : Releases heat

Endothermic : Takes in heat

Question 3

Define a catalyst

Answer 3

Catalysts are used to speed up a reaction rate which can be recovered unchanged.

Question 4

Equation to measure rate of reaction

Answer 4

change in property
——————————
change in time

Question 5

Describe the structure of an atom

Answer 5

Nucleus contains protons and neutrons. Electrons orbit around in different energy levels.

Question 6

What are ions?

Answer 6

A changed particle

Question 7

How are ions formed?

Answer 7

When an atom gains or loses electrons

Question 8

Why do atoms for ions?

Answer 8

to achieve a stable electron arrangement

Question 9

What can be said of the balance of protons and electrons in an atom compared to an ion?

Answer 9

atoms have equal amounts of protons to electrons

ions don’t have an equal amount for protons and electrons

Question 10

Why are atoms neutral?

Answer 10

the protons and electrons cancel out

Question 11

What’s the electron arrangement of any atom?

Answer 11

2
8
8
18

Question 12

In Nuclide notation where does the mass number go?

Answer 12

Top left

Question 13

How do you find the mass number?

Answer 13

Number of protons + number of electrons

Question 14

In nuclide notation where do you find the atomic number?

Answer 14

Bottom left

Question 15

How do you find the atomic number?

Answer 15

Number of protons

Question 16

What are isotopes?

Answer 16

Atoms of the same element which have different mass numbers

Isotopes have different numbers of neutrons

Question 17

On the periodic table, where do you find the atomic number

Answer 17

Above the letter

Question 18

What’s the valency equal to?

Answer 18

valency = charge

Question 19

What is RAM

Answer 19

Relative atomic mass

Question 20

Define RAM

Answer 20

the average mass of the isotopes present taking into account their relative proportions.

Question 21

What’s the most common isotope

Answer 21

Carbon

Question 22

Which atom is the atom against which all mass of all other atoms are compared to?

Answer 22

Carbon

6P , 6N, 6E

Question 23

How do you calculate RAM?

Answer 23

total mass of all atoms present
————————————————
number of atoms present

(% abundance X mass of isotope) + (same )
————————
100

Question 24

What is covalent bonding?

Answer 24

a chemical bond that involves the sharing of electron pairs between atoms

Question 25

What’s it called when’s. covalent bond shares 2 pairs of electrons?

Answer 25

Double covalent bond

Question 26

What are the different structures?

Answer 26

Linear Angular Pyramidal Tetrahedral

Question 27

What are discrete covalent molecules?

Answer 27

small and contain the number of atoms indicated in the formula, eg: CO2 has 3 atoms

Question 28

What is a covalent network?

Answer 28

giant structure with a huge number of atoms

Question 29

What is an intermolecular force?

Answer 29

weak forces of attraction

Question 30

Define ionic bond

Answer 30

when one element donates an electron (or electrons) to another so that both elements will have a full outer shell. a metal transfers an electron to a non metal

Question 31

Define metallic bonding

Answer 31

Metallic bond, force that holds atoms together in a metallic substance.

Question 32

How are atoms of a metallic bond arranged?

Answer 32

Metals consist of giant structures of atoms arranged in a regular pattern. The electrons from the outer shells of the metal atoms are delocalised , and are free to move through the whole structure.

Question 33

What’s special about electrons in metals?

Answer 33

They can move freely

Question 34

Covalent networks have a | _____ melting point

Answer 34

high

Question 35

What’s broken in covalent networks?

Answer 35

strong covalent bonds

Question 36

Do covalent bonds conduct electricity?

Answer 36

No, except graphite

Question 37

Covalent molecules have a ____ melting point?

Answer 37

low

Question 38

What’s broken in covalent molecules?

Answer 38

weak intermolecular forces

Question 39

Are covalent networks soluble in water?

Answer 39

no insoluble

Question 40

Do covalent molecules conduct electricity?

Answer 40

doesn’t conduct electricity in any state

Question 41

Are covalent molecules soluble in water?

Answer 41

they’re more likely to be soluble

Question 42

Ionic lattices have a ____ melting point

Answer 42

high

Question 43

What’s broken in an ionic lattice?

Answer 43

strong ionic bonds

Question 44

Do ionic lattices conduct electricity

Answer 44

only melted or in solution

Question 45

Are ionic lattices soluble in water?

Answer 45

more likely to be soluble