chem

Question 1

crystallisation

Answer 1

• place your solution into the evaporating dish
• heat gently using a water bath
• as it heats, crystals will start to form
• when they start to form, stop heating and let them cool
• as it cools, more crystals will form
• filter the crystals from the remaining solution
• let them dry by putting them somewhere warm

Question 2

how can ethanol be separated from water?

Answer 2

• ethanol has a lower boiling point than water so we use distillation
• first set up the distillation apparatus
• boil the mixture of ethanol and water
• ethanol will evaporate first
• then the ethanol vapour cools in the condenser
• it condenses back into a liquid and then is collected

Question 3

how do you separate an insoluble substance from a solution?

Answer 3

• we use filtration
• first place filter paper into the funnel
• pour the solution containing an insoluble substance through the funnel into the conical flask
• the solution will pass through the filter paper into the flask
• the insoluble substance will collect on the filter paper

Question 4

how could you separate salt from a mixture of salt and sand?

Answer 4

• salt is soluble and sand is insoluble
• you add water to the solution
• filter the solution to remove the insoluble sand
• the sand will collect on the filter paper
• evaporate the water to collect salt crystals

Question 5

what is a solute?

Answer 5

a solid that dissolves in a liquid

Question 6

what is a solvent?

Answer 6

the liquid that dissolves the solute.

Question 7

what are the three subatomic particles

Answer 7

electrons, neutrons and protons

Question 8

where are protons and neutrons located?

Answer 8

protons and neutrons are in the nucleus of an atom

Question 9

where are electrons located?

Answer 9

electrons are found in shells orbiting the nucleus

Question 10

what is the charge and mass of protons?

Answer 10

positive and a mass of 1

Question 11

what is the charge and mass of electrons?

Answer 11

negative and a mass of 0.005

Question 12

what is the charge and mass of neutrons?

Answer 12

no charge and mass of 1

Question 13

what are isotopes?

Answer 13

elements which have the same number of protons but a different number of neutrons

Question 14

what is the structure of elements?

Answer 14

on the 1st shell the maximum of electrons is 2
on the 2nd and 3rd shells the maximum is 8

Question 15

periods in the periodic table determine…

Answer 15

how much shells the element has, for example magnesium is in period 3 therefore it has 3 shells

Question 16

groups in the periodic table determine..

Answer 16

how much electrons are on the outershell of the element, for example group 1 element have 1 electron on their outer shell

Question 17

what is an element?

Answer 17

an element is a substance made from only one type of atom

Question 18

what is a compound?

Answer 18

a compound is made up of two or more elements chemically bonded together

Question 19

what is a molecule?

Answer 19

a molecule is made up of two or more atoms chemically bonded together

Question 20

what are the properties of a metal?

Answer 20

good conductors of heat and electricity, shiny, high melting point, ductile, sonorous, malleable, high density

Question 21

what are properties of non metals?

Answer 21

brittle, dull, poor conductors of heat and electricity

Question 22

what are mixtures?

Answer 22

a mixture contains 2 or more substances (elements or compounds) that are not chemically joined