Principals of Chemistry

Question 1

What are the properties of solids

Answer 1

• fixed shapes/volumes
• vibrate/ little movement of particles
• tightly packed
• less kinetic energy
• not compressible

Question 2

What are the properties of liquids

Answer 2

• loose shape/ fixed volume
• vibrate stronger/ more movement
• loosely packed
• more kinetic energy
• slightly compressible

Question 3

What are the properties of gases

Answer 3

• no fixed shape/ volume
• vibrate a lot/ move around much more
• particles are independent
• more kinetic energy
• highly compressible

Question 4

structure of a solid

Answer 4

• arranged in perfect rows
• every particle is joined
• can vibrate but not move

Question 5

structure of a liquid

Answer 5

• arranged irregularly
• some particles touch while other don’t
• particles move/slide past each other in random directions

Question 6

structure of a gas

Answer 6

• gases have no arrangement
• no particles are joined
• they move around and collide but do not stay together
• move in random directions
• they are free

Question 7

solid–>liquid

Answer 7

melting

Question 8

solid–>gas

Answer 8

sublimation

Question 9

liquid–>solid

Answer 9

freezing

Question 10

liquid–>gas

Answer 10

evaporation/boiling

Question 11

gas–>liquid

Answer 11

condensation

Question 12

gas–>solid

Answer 12

deposition

Question 13

what is the kinetic theory?

Answer 13

gases increase in temperature
– they gain kinetic energy and move faster
gases increase in pressure
– they loose space and therefore move less

Question 14

what happens when a solid melts

Answer 14

particles gain kinetic energy, vibrate faster, their bonds between the particles weakens, snd so they have more energy to break free of the bonds

Question 15

what happens when liquid evaporates

Answer 15

particles will gain more kinetic energy, making particles move around more, weakening their bonds until the boiling point, where they break freely of any bond

Question 16

what happens when a liquid freezes

Answer 16

the particles will not have enough energy, so more bonds begin to form, fixing the particles in place

Question 17

what is diffusion

Answer 17

the net movement of particles form an area of their high concentration, to an area of their low concentration until it is evenly spread

Question 18

elements

Answer 18

are pure and made up of only 1 type of atom (periodic table)

Question 19

compounds

Answer 19

are made of two or more elements chemically bonded

Question 20

mixtures

Answer 20

are two or more substances that are not chemically bonded

Question 21

properties of metals

Answer 21

• electrical and thermal conductors
• malleable
• ductile
• high melting/ boiling points

Question 22

properties of non-metals

Answer 22

• electrical and thermal insulators
• brittle
• low melting/ boiling points

Question 23

equiptments

Answer 23

time = stopwatch
temp = thermometer
mass = balance
volume = measuring cylinder/ burette/ pipette

Question 24

filtration

Answer 24

separation of insoluble solids and a solvent

Question 25

method for filtration

Answer 25

- set up the materials (filter paper, funnel, conical flask) - add solution in the set up - wait for the mixture to separate (the residue will remain in the funnel but the filtrate will drop to the conical flask) - leave the residue to dry

Question 26

evaporation/ crystallization

Answer 26

separation of the solvent and the soluble solid/solvent

Question 27

method for evaporation/ crystallization

Answer 27

- set up the materials (evaporating basin, bunsen burner, heat proof mat, gauze, stand) - put the mixture in the evaporating basin - heat the mixture until 2/3 of the water is gone and crystals form - leave it in a warm place until the saturated solution crystallizes

Question 28

distillation

Answer 28

separation of a solute and a solvent, from a mixture or separation of 2 different liquids with different boiling points

Question 29

methods for distillation

Answer 29

- mixture is put into a flask - the mixture is heated and forms steam - the steam gets in the condenser - cold water from outside the condenser cools down the steam - the steam condenses to its pure form of water - water runs down the beaker

Question 30

solvent

Answer 30

substance that dissolves a solute (liquid or gas)

Question 31

solute

Answer 31

substance that is dissolved in a solvent (solid)

Question 32

solution

Answer 32

mixture of one or more solutes dissolved in a solvent

Question 33

saturated solution

Answer 33

a solution containing the max concentration of a solute dissolved in the solvent at specific temperatures

Question 34

residue

Answer 34

the substance that remains after purification methods

Question 35

filtrate

Answer 35

the liquid or solution that has passed through a filter

Question 36

how to test the purity of substances

Answer 36

use their melting points, they will have sharp and definite melting points

Question 37

chromatography

Answer 37

is used to separate mixtures of soluble colored substances (inks) from water

Question 38

how to compare unknown substances

Answer 38

by comparing the color and placement of the dots (shapes in diagrams)

Question 39

how to compare pure and impure

Answer 39

by seeing which have 2 or more substances and which one have 1

Question 40

why do we use the Rf value

Answer 40

to identify unknown substances.

Question 41

Rf value =

Answer 41

total distance travelled by the substance/ total distance travelled by the solvent