Chemistry 6-Chemical change

Question 1

What can irritants do?

Give an example

Answer 1

cause reddening / blistering of the skin

Bleach

Question 2

What do Alkali’s form when placed in water?

Answer 2

OH- ions

Question 3

What do Acids form when placed in water?

Answer 3

H+ ions

Question 4

Acid + Base=

Answer 4

Salt+water

Question 5

H+ + OH- =

Answer 5

H20

Question 6

What do acids do to produce hydrogen ions in water?

Answer 6

Ionise

Question 7

Give an example of a monoprotic acid

Answer 7

It gives off 1H+

HCl

Question 8

Give an example of a diprotic acid

Answer 8

It gives off 2H+

H2SO4

Question 9

Give an example of a triprotic acid

Answer 9

Phosphoric acid (H3PO4)

It gives off 3H+

Question 10

What do strong acids do that weak acids dont do?

Answer 10

Strong acids fully ionise

weak acids dont fully ionise

Question 11

Define ionising

Answer 11

Releasing of all H+

Question 12

Name 3 weak acids that dont fully ionise when placed in water

Answer 12

ethanoic

citric

carbonic

Question 13

Ionisation of weak acids are what type of reaction?

Answer 13

Reversible

Question 14

Which side of the equilibrium do weak acids lie

Answer 14

left hand side

Question 15

Acid strength shows what

Answer 15

What proportion of the acid molecules ionise in water

Question 16

Concentration of an acid measures what

Answer 16

how many moles of acid molecules are in 1 litre of water

Question 17

The more moles of acid molecules per dm3, the …

Answer 17

more concentrated the acid is

Question 18

You can have a dilute but. …

or a concentrated but ….

Answer 18

strong acid

weak acid

Question 19

Why does ethanoic acid have a much lower electrical conductivity than HCl?

Answer 19

HCl is a stronger acid with more H+ that are ionised

Ions carry charge

Question 20

Acid + Metal =

Answer 20

Salt + Hydrogen

Question 21

What sort of experiment can prove the acid+metal equation

Answer 21

Squeeky pop test with a burning splint

Question 22

Why doesnt copper react with dilute acids?

Answer 22

less reactive than hydrogen

Question 23

Nitric acid reacting with metals produce what instead of salt + Hydrogen?

Answer 23

Nitrogen oxides

Question 24

Some metal hydroxides / oxides are what?

Hence what equation can be applied

Answer 24

Bases

Acid + metal oxide = salt + Water

Question 25

Combination of a metal and its acid determines what

Answer 25

the name of the salt

Question 26

Acid + Metal carbonates =

Answer 26

Salt + Water + CO2

Question 27

Are common salts of Na / K / Ammonium soluble in water?

Answer 27

Yes

Question 28

Are nitrates soluble in water?

Answer 28

Yes

Question 29

Are common Chlorides soluble in water?

Answer 29

Yes Except Silver Chloride + lead Chloride

Question 30

Are common sulphates soluble in water?

Answer 30

Yes Except lead,barium,calcium sulphate

Question 31

Which carbonates / hydroxides are soluble in water?

Answer 31

sodium/potassium/ammonium The rest are insoluble

Question 32

How do you form insoluble salts

Answer 32

Using precipitation method Adding two soluble salts together Formation of an insoluble salt

Question 33

How do you form soluble salts? (Insoluble reactant)

Answer 33

Acid + Metal or an insoluble base (metal oxide/hydroxide)

Question 34

Give an example of the formation of a soluble salt equation

Answer 34

Copper oxide + hydrochloric acid =copper chloride

Question 35

How do we make soluble salts using an acid and a soluble reactant?

Answer 35

Titration of alkali is needed to neutralise the acid Then evaporate the water to form dry salt

Question 36

An oxidising agent does what with electrons

Answer 36

Accepts electrons and gets REDUCED

Question 37

a reducing agent does what with electrons

Answer 37

donates electrons and gets OXIDISED

Question 38

With Iron(2) salt and chlorine gas, what colour does the solution turn from into? What happens to the Iron?

Answer 38

Green to Yellow Loses an electron to form Fe3+

Question 39

With the iron(2)and chlorine, what is the reducing agent and why?

Answer 39

Iron is, as it donates an electron to the chlorine

Question 40

With the iron(2) and chlorine, what is the oxidising agent and why?

Answer 40

Chlorine, as it accepts the electron from iron

Question 41

Iron and a dilute acid, what gets oxidised and what gets reduced?

Answer 41

iron is the reducing agent and is being oxidised the dilute acid will be the oxidising agent and is being reduced

Question 42

Name the order of reactivity of metals

Answer 42

Magnesium Zinc Iron Tin

Question 43

WIth displacment reactions with metals, what is alwasy being oxidised?

Answer 43

Metal atom (the more reactive metal)

Question 44

with displacement reactions with metals, what is always being reduced?

Answer 44

Metal ion (the less reactive metal)

Question 45

the equation for rust is

Answer 45

iron + oxygen + water = hydrated Iron (3) oxide

Question 46

Rust is redox reaction thus what is being oxidised and what is being reduced? Whats the reducing agent/oxidising agent

Answer 46

Iron= oxidised and thus reducing agent oxygen=reduced and thus oxidising agent

Question 47

steels are alloys with what other things

Answer 47

iron carbon other metals

Question 48

stainless steel contains what 3 things

Answer 48

iron/carbon/chromium

Question 49

Tin plating to prevent rust can be found where

Answer 49

food cans

Question 50

Galvanising involves what?

Answer 50

adding a zinc which is a more reactive metal than iron this loses electrons to oxygen instead of iron steel buckets/corrugated iron roofing

Question 51

what can be also placed on ships/iron pipes as a sacrificial method?

Answer 51

Magnesium as its a more reactive metal