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GCSE Chemistry > C5 - Chemical Change > Flashcards

C5 - Chemical Change Flashcards

1
Q

What is Titration?

A

where a solution of known concentration is used to determine the concentration of an unknown solution

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2
Q

What is the formula triangle for concentration, number of moles and volume?

A

Number of moles
—————————-
Concentration X Volume

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3
Q

What is the equation to convert a concentration in mol/dm°3 into g/dm°3?

A

Mass in grams = moles x relative formula mass

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4
Q

What does the pH scale go from?

A

0 to 14

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5
Q

What does a lower pH of a solution mean?

A

More acidic

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6
Q

What does a higher pH of a solution mean?

A

More alkaline

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7
Q

What pH does a neutral substance have?

A

7

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8
Q

What is an example of a nuetral substance with a pH of 7?

A

Pure water

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9
Q

What is an acid?

A

A substance that forms aqueous solutions with a pH of less than 7

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10
Q

What is a base?

A

A substance with a pH greater than 7

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11
Q

What is an alkali?

A

A base that dissolves in water to form a solution

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12
Q

What is neutralisation?

A

The reaction between acids and bases

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13
Q

What do alkalis form in water?

A

OH- ions

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14
Q

What does an acid + a base form?

A

Acid + base ——> salt + water

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15
Q

What is pH just a measure of?

A

How acidic or alkaline a solution is

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16
Q

What is pH just a measure of?

A

How acidic or alkaline a solution is

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17
Q

How can you measure pH?

A

Using Universal/Single indicators

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18
Q

What is the benefit of the pH probe compared to the indicators when meauring pH?

A

More accurate and precise as doesnt require human judgement

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19
Q

What is the benefit of the pH probe compared to the indicators when meauring pH?

A

More accurate and precise as doesnt require human judgement

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20
Q

What do neutralisation reactions always produce?

A

Salt and water

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21
Q

What pH would a neutralisation reaction produce?

A

A neutral pH of 7

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22
Q

What are the 3 common acids? And what are their formulas?

A

Hydrochloric acid (HCl)
Sulfuric acid (H2SO4)
Nitric acid (HNO3)

23
Q

What are the 2 common bases? And what are their formulas?

A

Sodium hydroxide (NaOH)
Calcium carbonate (CaCO3)

24
Q

What makes an acid strong?

A

If the ionise completely

25
Q

What does the term ‘ionise completely’ when talking about strong acids?

A

The reactants turn completely into products

26
Q

As the concentration of hydrogen ions gets higher, the pH gets _______

A

Lower

27
Q

Does a low pH have a high or low concentration of hydrogen ions?

A

High

28
Q

What is the product of an acid + a metal carbonate?

A

Salt + water + CO2

29
Q

Explain how you would carry out the making of soluble salts using an insoluble base experiment?

A

1.Place dilute HCL acid into a beaker and gently heat with a bunsen burner
2.Then keep adding an insoluble base a bit at a time until the base no longer disappears
3.Filter out excess base and put the solution in a water bath
4. Stop when you see crystals and leave it to cool

30
Q

Explain how you would carry out the making of soluble salts using an insoluble base experiment?

A

Place dilute HCL acid into a beaker and gently heat with a bunsen burner
Then keep adding an insoluble base a bit at a time until the base no longer disappears

31
Q

In the making soluble salts using an insoluble base experiment, what does it mean when the base is no longer dissapearing?

A

All of the acid has been neutralised

32
Q

When we talk about the reactivity of a metal, what does it mean in terms of ions?

A

How easily it forms positive ions (loses electrons)

33
Q

What is oxidation?

A

The process of gaining oxygen

34
Q

What is reduction?

A

The loss of oxygen

35
Q

What do relative reactions of metals with water produce?

A

A metal hydroxide and hydrogen gas

36
Q

What does OIL RIG stand for?

A

Oxidation is loss (of electrons)
Reduction is gain (of electrons)

37
Q

Metal oxides
Metal hydroxides
Metal carbonates.
What do they have in common?

A

They are all neutralisation reactions

38
Q

What are the products when a metal oxide and an acid react?

A

Salt + water

39
Q

What are the products when a metal hyroxide and an acid react?

A

Salt + water

40
Q

When we say a metal forms positive ions?

A

It loses its electron(s) and becomes positive

41
Q

“Pretty Silly Lions Catch Many Clever Zebras In Huge Cuages”

A

Potassium
Sodium
Lithium
Calcium
Magnesium
Carbon
Zinc
Iron
Hydrogen
Copper

42
Q

More reactive metals can _________ less reactive metals

A

Displace

43
Q

If you put magnesium into a solution of Iron Sulfate, what will the products be and why?

A

MAGNESIUM would displace the IRON to form MAGNESIUM SULFATE

because Mg is more reactive than Fe

44
Q

How do you extract metal from metal oxides?

A

React the metal oxide with carbon. The carbon will take the oxygen to form CO2
You will now have metal + CO2

45
Q

When you extract metal from metal oxides, using carbon, your products will be metal + CO2

What has reduced and what has become oxidised

A

The metal oxide has been reduced (to form metal)
The Carbon has been oxidised (to form CO2)

46
Q

What is the other way you could extract metal from metal oxides that is really expensive? (without using carbon)

A

Electrolysis

47
Q

Show the redox half equation for Ca.

A

Ca2+ + 2e- ——> Ca

48
Q

Explain how you would carry out a titration experiment.

A
  1. Use a pipette to transfer 25cm3 of sodium hydroxide into a clonical flask
  2. Add 5 drops of indicator like methyl orange
  3. Place onto a white tile to see the colour change clearly
  4. Fill a burette with sulfuric acid
  5. Slowly add the acid to the solution (while swirling) until it is neutralised
49
Q

What is the product of hydrogen + hydroxide?

A

Water

50
Q

Hydrogen reacts with hydroxide to produce water?
What is the symbol equation for this?

A

H+ + OH- —–» H2O

51
Q

What is the purpose of a Titration experiment?

A

To determine the concentration of an unknown solution

52
Q

Why are Universal Indicators used for titrations?

A

To estimate the pH of a solution by examining colour change

53
Q

Why would you use single indicators for titration?

A

You want to see a sudden colour change

GCSE Chemistry (15 decks)

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