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chemistry gcse > chemical changes (paper 1) > Flashcards

chemical changes (paper 1) Flashcards

1
Q

sodium reacting with oxygen observation

A

bright yellow flame, explosive , really quick

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2
Q

iron reacting with oxygen observations

A

sparks, glowed yellow

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3
Q

copper reacting with oxygen observations

A

turns black

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4
Q

magnesium reacting with oxygen observations

A

bright white flame, strip turns to white powder

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5
Q

what is oxidation

A

when something gains oxygen

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6
Q

what does metal + oxygen make

A

a metal oxide

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7
Q

what does a metal and water make

A

metal hydroxide + hydrogen

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8
Q

lithium and water reaction observation

A

floated on the top of the water

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9
Q

sodium reacting with water observation

A

bit of sparks, reaction happened quicker, moved around the surface really fast, fizzed

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10
Q

potassium reacting with water observation

A

lilac flame, exploded, sparks

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11
Q

symbol for sulphuric acid

A

H SO
2. 4

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12
Q

symbol for nitric acid

A

HNO
3

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13
Q

what does a metal + acid make

A

salt + hydrogen

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14
Q

reactivity series

A

potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
tin
lead
hydrogen
copper
silver
gold
platinum

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15
Q

what is a displacement reaction

A

when a more reactive metal can displace a less reactive metal from a compound

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16
Q

what happens to electrons in oxidation

A

loses electrons

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17
Q

what happens to electrons during reduction

A

gains electrons

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18
Q

when writing half equations for oxidation where are the electrons

A

on the right hand side of the arrow

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19
Q

when writing half equations for reduction where are the electrons

A

left hand side of the arrow

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20
Q

what is a redox reaction

A

when a substance has been oxidised and a substance has been reduced at the same time

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21
Q

what are indicators and examples of them

A

substances that change colour to tell you if something is an acid or an alkali

such as litmus paper or universal indicator

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22
Q

what ions do acids form in a solution

A

H plus

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23
Q

what is a base

A

metal oxide or metal hydroxide that’s insoluble e.g copper oxide

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24
Q

what is an alkali

A

metal hydroxide that’s soluble eg sodium hydroxide solution

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25
Q

what ions do alkalis form when in a solution

A

OH minus ions

26
Q

what number on the ph scale are strong or weak acids

A

1 - 3 = strong acid

4 - 6 = weak acid

27
Q

what numbers on the periodic table are strong or weak alkalis

A

8 - 11 = weak alkali

12 - 14 = strong alkali

28
Q

base + acid

A

salt + water

29
Q

metal + acid

A

salt + hydrogen

30
Q

metal carbonate + acid

A

salt + water + carbon dioxide

31
Q

acid + alkali

A

salt + water

32
Q

method for base + acid

A

react

filter

evaporation

crystallise

33
Q

method for metal + acid

A

react

filter

evaporation

crystallise

34
Q

method for acids and metal carbonates

A

react

filter

evaporation

crystallise

35
Q

method for acid + alkali

A

acid + universal indicator

add alkali until neutral

evaporate

crystallise

36
Q

what is the test for carbon dioxide

A

lime water turns cloudy

37
Q

method for the preparation of a salt

A

measure out acid in put into beaker

set up bunsen burner, tripod, gauze and heatproof mat. Put the beaker on the gauze and heat the acid gently until it is almost boiling

turn off bunsen burner and remove the beaker from the tripod

use spatula to add a small amount of copper oxide powder to the hot acids and stir with glass rod

the copper oxide will disappear and the solution will turn clear blue

add more copper oxide and stir keep adding it until it is in excess

set up the filter funnel and paper over the conical flash and filter the contents of the beaker

pour the filtrate from the conical flask into the evaporating basin

set up water bath using the beaker on the tripod and gauze and evaporate gently using the water bath

leave the evaporating basin on a window sill for a couple of days until all the liquid has evaporated and only crystals remain

38
Q

steps for writing ionic equations

A
  1. rewrite the equation showing the seperate ions present in each substance
  2. remove any spectator ions (ions that don’t change state or charge)
  3. rewrite out the equation without the spectator ions
39
Q

solvent

A

a liquid that a solid can dissolve into

40
Q

solute

A

a solid that can dissolve into a liquid

41
Q

what are the units for concentration

A

decimetres cubed

dm^3

42
Q

how do you change cm^3 to dm^3

A

divide by a thousand

43
Q

equation for concentration

A

mass of solute
————————
volume of solvent

44
Q

describe how a change in mass of solute would affect the concentration

A

if we increase the mass, the concentration will increase

if we decrease the mass, the concentration will decrease

45
Q

describe how a change in volume of a solvent would affect the concentration

A

decreasing the volume , increases the concentration

increasing the volume, will decrease the concentration

46
Q

what do strong acids do in water

A

completely ionise (the ions split up)

means they have a high concentration of H plus ions means low ph

this is not reversible

47
Q

what do weak acids do in water

A

partially ionise in water ( only a small amount of acid molecules split up)

means they have a low concentration of H plus ions means higher pH

this reaction is reversible

48
Q

equation for pH

A

-log (H plus)

49
Q

equation for hydrogen ion

A

(H plus ) = 10 ^ pH

50
Q

method for titration

A

using a pipette and pipette filler fill the conical flask with 25 cx cubed if sodium hydroxide solution then add 5 drops of indicator and place under a white tile

add the dilute sulphuric acid to the burette and make sure the sulphuric acid starts at 0.00

slowly add sulphuric acid to the conical flask swirling all the time until you see the colour begin to change

then add drop wise until all the colour changes

record the volume of sulphuric acid in the burette added to 2 decimal place

read from the bottom of the meniscus

51
Q

what is a concordant result

A

the two titres that are within 0.1 cm cubed of each other

52
Q

steps for titration model answer

A
  1. write down the known and unknown for the substances, their concentrations and volumes
  2. workout the number of moles for the known
  3. workout the ratio using the equation
  4. work out the unknown concentration
  5. covert to g/ dm cubed if you have to
53
Q

equation for moles (titration question)

A

concentration x volume
——————————-
1000

54
Q

how do you convert mol/dm cubed to g/dm cubed

A

conc (mol/dm cubed) x Mr for the substance

55
Q

what colour does phenolphthalein indicator go in acids and alkalis

A

acids = colourless

alkalis = pink

56
Q

what colour does litmus indicator go in acids and alkalis

A

acids = red

alkalis = blue

57
Q

what colour does methyl orange indicator go in acids and alkalis

A

acids = red

alkalis = yellow

58
Q

how do you calculate the H+ ion concentration changes

A

10^-x

x = the difference in pH , found by subtracting the starting pH from the final pH

59
Q

metal + water

A

metal hydroxide + hydrogen

60
Q

what metals in the reactivity series are extracted by reduction with carbon

A

everything below carbon in the reactivity series

61
Q

what metals in the reactivity series are extracted by using electrolysis

A

everything above carbon in the reactivity series

chemistry gcse (11 decks)

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