Basic Concepts

Question 1

what can elements consist of

Answer 1

separate atoms (e.g helium)
simple covalent molecules (oxygen)
giant stuctures (diamond)

Question 2

what is a compound

Answer 2

a substance that contains two or more substances chemically combined. the amounts of each element are in fixed proportions

Question 3

how can a compound be broke down

Answer 3

by chemical means and not by physical methods

Question 4

a compound may consist of

Answer 4

• simple molecules (h2o water)
• giant ionic structures (nacl)
• giant covalent structures (sio2)

Question 5

what is the atomic number

Answer 5

number of protons in the nucleus if an atom. it also tells you the number of electrons in the shells surrounding

Question 6

what is the mass number

Answer 6

sum of protons and neutrons in the nucleus

Question 7

what is a positive ion

Answer 7

cation

Question 8

what is a negative ion

Answer 8

anion

Question 9

what is the group number

Answer 9

number of outer shell electrons

Question 10

what is the electronic configuration

Answer 10

shows number of electrons in each shell

Question 11

typical acid reactions

Answer 11

acid + alkali -> salt and water
acid + base -> salt and water
acid + carbonate -> salt and co2 and water
acid + metal -> salt and hydrogen

Question 12

what is an acid solution

Answer 12

contains h+ ions. turns litmus red

Question 13

what are alkalines

Answer 13

contain OH- ions. turn litmus blue

Question 14

complete combustion

Answer 14

hydrocarbon + oxygen -> carbon dioxide and water

Question 15

what is fractional distillation used for

Answer 15

separating liquids with similar boiling points

Question 16

example of fractional distillation

Answer 16

separating water from ethanol

Question 17

what is using a separating funnel separate

Answer 17

immiscible liquids

Question 18

example for using a separating funnel

Answer 18

separating oil from water

Question 19

what does paper chromatography separate

Answer 19

separating the components in a mixture. mostly used to identify what is in a mixture

Question 20

example for paper chromatography

Answer 20

separating components of food colouring

Question 21

what is relative atomic mass

Answer 21

the ratio of average mass of one atom of an element to one twelfth of the mass of an atom carbon 12

Question 22

what are isotopes

Answer 22

atoms of the same number of protons but different numbers of neutrons

Question 23

what do isotopes have similar

Answer 23

chemical properties

Question 24

how to work out the relative atomic mass of something

Answer 24

percentage multiplied by the number of carbons added together and divided by 100

Question 25

what is an element

Answer 25

substance that cannot be separated into anything simpler. it contains only one type of atom