Chemistry unit 1

Question 1

what is an example of a non metal

Answer 1

carbon, bromine, neon

Question 2

where are nonmetals found in the periodic table

Answer 2

the right side of the stair case

Question 3

what is an example of a semi metal

Answer 3

boron, silicon, arsenic

Question 4

what are semi metals

Answer 4

substances that display both non-metallic and metallic properties

Question 5

what is an example of a metal

Answer 5

silver, nickel, lead

Question 6

where are metals found in the periodic table

Answer 6

the left side of the stair case

Question 7

name 4 reasons most water not drinkable

Answer 7

because it contains
- dissolved salts
- microorganisms
- pollutants e.g sewage
- dissolved gases e.g co2

Question 8

what are the 3 main stages to purifying water

Answer 8

-sedimentation
-filtration
-chlorination

Question 9

what is sedimentation

Answer 9

allowing solids to sink to the bottom of the water in order to filter them out

Question 10

what is filtration

Answer 10

when water is passed through a filter bed

Question 11

what is a filter bed

Answer 11

a mixture of stones, gravel, coarse and fine sand that remove solids in water to allow only bacteria and viruses to remain

Question 12

what is chlorination

Answer 12

chlorine is added to water to kill bacteria

Question 13

why is sulfur dioxide bubbled through water

Answer 13

to remove excess chlorine

Question 14

how is drinking water transported

Answer 14

by underground sealed pipes

Question 15

name 3 advantages of fluoridation

Answer 15

-decreases enamel decay
-makes teeth stronger
-prevents cavities

Question 16

what is fluoridation

Answer 16

Fluoridation is the addition of fluoride to a water supply

Question 17

name 3 disadvantages of fluoridation

Answer 17

-more effective in toothpaste than in water
-too much fluoride can cause fluorosis
-can cause bone cancer in males

Question 18

name 2 people that may support the addition of fluoride to water

Answer 18

-dentists
-health workers

Question 19

what is desalination

Answer 19

obtaining pure drinking water from dirty or salty water

Question 20

how is desalination done

Answer 20

using reverse osmosis filters to filter the dirty water under pressure

Question 21

give 3 reasons why desalination is bad

Answer 21

-expensive
-uses lots of energy
-the by-product is very salty water and so must be disposed of carefully

Question 22

what is distillation

Answer 22

the process of separating liquids or dissolved solids from a liquid mixture by using boiling and condensation

Question 23

what is hard water

Answer 23

hard water is water that has a lot of calcium compounds dissolved in it

Question 24

why can water be hard

Answer 24

because sometimes water passes through calcium containing (gypsum) rocks that dissolve into the water making it hard

Question 25

how do you remove the hardness from temporary hard water

Answer 25

by boiling it

Question 26

name 3 advantages of hard water

Answer 26

-some people prefer the taste -calcium is good for bones -good for brewing beer

Question 27

name 3 disadvantages of hard water

Answer 27

-limescale build up can damage metal appliances -pipes can become blocked from limescale -scum forms in reaction with soap

Question 28

how is limescale formed

Answer 28

calcium ions + hydrogen carbonate ions --> calcium carbonate (limescale) + carbon dioxide + water

Question 29

how to make hard water not hard

Answer 29

using an ion exchange column

Question 30

how does an ion exchange column remove water hardness

Answer 30

the column is filled with a resin that holds sodium ions. as hard water passes through the calcium ions and sodium ions swap. the water that comes out contain no calcium ions so is no longer hard.

Question 31

what is solubility

Answer 31

a soluble particle is one that can dissolve into a substance

Question 32

draw a flow chart outlining the main steps of the purification of water

Answer 32

reservoir -> sedimentation tank -> filtration -> addition of chlorine ->clear water tank -> storage reservoir -> mains supply

Question 33

what is the inner core of the earth made of

Answer 33

solid iron and nickel due to the high pressure

Question 34

what is the outer core of the earth made of

Answer 34

liquid iron and nickel

Question 35

what is the mantle of the earth made of

Answer 35

semi-molten rock that can behave like a liquid

Question 36

what is the crust of the earth made of

Answer 36

solid outer layer floating on the mantel

Question 37

how thick is the crust of the earth

Answer 37

between 5 and 70 km thick

Question 38

where in the earth is the magnetic field produced

Answer 38

in the outer core

Question 39

who in 1915 first suggested the idea of continental drift

Answer 39

Alfred Wegener

Question 40

what is continental drift

Answer 40

the gradual movement of the continents across the earth's surface through time.

Question 41

why did Alfred Wegener think that all the continents were once all one piece?

Answer 41

- the jigsaw fit of the coastlines of africa and south america - similar rocks were found at both sites - fossil animals found only South America and Africa, could be found on many continents.

Question 42

give an example of a strong alkali

Answer 42

bleach pH 13

Question 43

give an example of a weak alkali

Answer 43

baking soda pH 9

Question 44

give an example of a weak acid

Answer 44

tomato juice pH 4

Question 45

give an example of a strong acid

Answer 45

gastric acid pH 1

Question 46

finish the equation acid + metal --> _________ + _______

Answer 46

salt and hydrogen

Question 47

finish the equation acid + metal hydroxide/ oxide --> _________ + _______

Answer 47

salt and water

Question 48

finish the equation acid + metal carbonate --> _________ + _______ + _________

Answer 48

salt and water and carbon dioxide

Question 49

what is the name of a salt created from hydrochloric acid

Answer 49

chloride

Question 50

what is the name of a salt created from sulfuric acid

Answer 50

sulfate

Question 51

what is the name of a salt created from nitric acid

Answer 51

nitrate

Question 52

what are titrations

Answer 52

controlled reactions between acids and alkalis

Question 53

what can titrations be used to calculate

Answer 53

unknown concentrations

Question 54

what is the gas test for hydrogen

Answer 54

burns with a squeaky pop

Question 55

what is the gas test for carbon dioxide

Answer 55

turns limewater cloudy

Question 56

what is the gas test for oxygen

Answer 56

re-lights a glowing splint

Question 57

what 4 factors can affect the rate of chemical reactions

Answer 57

- temperature (kinetic energy) - concentration - surface area - adding a catayst

Question 58

how does raising the temperature impact the rate of reaction

Answer 58

- makes particles collide more frequently as they have more kinetic energy - makes it more likely that collisions result in reactions as the particles collide with more energy

Question 59

how does increasing the concentration impact the rate of reaction

Answer 59

- a higher concentration means there are more particles in a given volume - this means more successful collisions so a faster rate

Question 60

how does adding a catalyst impact the rate of reaction

Answer 60

- speeds up reaction with being chemically changed - allow particles to collide in different ways - increases the rate of reaction

Question 61

why is there a gradual loss of mass in some chemical reactions

Answer 61

because gas is emitted over time