Chemistry 6-Chemical change Flashcards Preview

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Flashcards in Chemistry 6-Chemical change Deck (51)
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1
Q

What can irritants do?

Give an example

A

cause reddening / blistering of the skin

Bleach

2
Q

What do Alkali’s form when placed in water?

A

OH- ions

3
Q

What do Acids form when placed in water?

A

H+ ions

4
Q

Acid + Base=

A

Salt+water

5
Q

H+ + OH- =

A

H20

6
Q

What do acids do to produce hydrogen ions in water?

A

Ionise

7
Q

Give an example of a monoprotic acid

A

It gives off 1H+

HCl

8
Q

Give an example of a diprotic acid

A

It gives off 2H+

H2SO4

9
Q

Give an example of a triprotic acid

A

Phosphoric acid (H3PO4)

It gives off 3H+

10
Q

What do strong acids do that weak acids dont do?

A

Strong acids fully ionise

weak acids dont fully ionise

11
Q

Define ionising

A

Releasing of all H+

12
Q

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

A

ethanoic

citric

carbonic

13
Q

Ionisation of weak acids are what type of reaction?

A

Reversible

14
Q

Which side of the equilibrium do weak acids lie

A

left hand side

15
Q

Acid strength shows what

A

What proportion of the acid molecules ionise in water

16
Q

Concentration of an acid measures what

A

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

17
Q

The more moles of acid molecules per dm3, the …

A

more concentrated the acid is

18
Q

You can have a dilute but. …

or a concentrated but ….

A

strong acid

weak acid

19
Q

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

A

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

Ions carry charge

20
Q

Acid + Metal =

A

Salt + Hydrogen

21
Q

What sort of experiment can prove the acid+metal equation

A

Squeeky pop test with a burning splint

22
Q

Why doesnt copper react with dilute acids?

A

less reactive than hydrogen

23
Q

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

A

Nitrogen oxides

24
Q

Some metal hydroxides / oxides are what?

Hence what equation can be applied

A

Bases

Acid + metal oxide = salt + Water

25
Q

Combination of a metal and its acid determines what

A

the name of the salt

26
Q

Acid + Metal carbonates =

A

Salt + Water + CO2

27
Q

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

A

Yes

28
Q

Are nitrates soluble in water?

A

Yes

29
Q

Are common Chlorides soluble in water?

A

Yes

Except Silver Chloride + lead Chloride

30
Q

Are common sulphates soluble in water?

A

Yes

Except lead,barium,calcium sulphate

31
Q

Which carbonates / hydroxides are soluble in water?

A

sodium/potassium/ammonium

The rest are insoluble

32
Q

How do you form insoluble salts

A

Using precipitation method

Adding two soluble salts together

Formation of an insoluble salt

33
Q

How do you form soluble salts? (Insoluble reactant)

A

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

34
Q

Give an example of the formation of a soluble salt equation

A

Copper oxide + hydrochloric acid =copper chloride

35
Q

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

A

Titration of alkali is needed to neutralise the acid

Then evaporate the water to form dry salt

36
Q

An oxidising agent does what with electrons

A

Accepts electrons and gets REDUCED

37
Q

a reducing agent does what with electrons

A

donates electrons and gets OXIDISED

38
Q

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

What happens to the Iron?

A

Green to Yellow

Loses an electron to form Fe3+

39
Q

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

A

Iron is, as it donates an electron to the chlorine

40
Q

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

A

Chlorine, as it accepts the electron from iron

41
Q

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

A

iron is the reducing agent and is being oxidised

the dilute acid will be the oxidising agent and is being reduced

42
Q

Name the order of reactivity of metals

A

Magnesium

Zinc

Iron

Tin

43
Q

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

A

Metal atom (the more reactive metal)

44
Q

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

A

Metal ion (the less reactive metal)

45
Q

the equation for rust is

A

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

46
Q

Rust is redox reaction thus what is being oxidised and what is being reduced?

Whats the reducing agent/oxidising agent

A

Iron= oxidised and thus reducing agent

oxygen=reduced and thus oxidising agent

47
Q

steels are alloys with what other things

A

iron

carbon

other metals

48
Q

stainless steel contains what 3 things

A

iron/carbon/chromium

49
Q

Tin plating to prevent rust can be found where

A

food cans

50
Q

Galvanising involves what?

A

adding a zinc which is a more reactive metal than iron

this loses electrons to oxygen instead of iron

steel buckets/corrugated iron roofing

51
Q

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

A

Magnesium as its a more reactive metal