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Flashcards in C3 Deck (30)
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1

What is hard water?

water that contains dissolved mg2+ or ca2+ ions. The ions enter the water when slightly acidic rain (formed by dissolved co2)flows over rocks containing magnesium/calcium carbonate or magnesium/calcium sulphate.

2

What are the different types of hardness?

Temporary and Permanent

3

What does temporary hard water contain?

Ca2+/mg2+ and HCO3- ions

4

How can the hardness be removed by heating the temporary hard water?

Ca2+ + HCO3- = CaCO3 + H2O + CO2
aq aq solid liquid gas

5

What does permanent hard water contain?

Ca2+/Mg2+ and SO42- ions

6

How can the hardness be removed by heating the permanent hard water?

By adding Na2CO3. Na+ ions replace Ca2+ ions in the solution forming insoluble precipitate calcium carbonate

7

In group 1 (alkali metals) describe the denseness?

Goes from most to least dense

8

What are the patterns of the group 7 elements (halogens)?

Increases in boiling point as you go down
Goes from lightest to darkest

9

What are transition metals like compared to group 1 and 2 metals?

unreactive
high melting points (apart from mercury)
strong and hard
high density
makes coloured compounds
are as useful as catalysts

10

In the chemical test when testing for aluminium, calcium and magnesium, what chemicals or conditions are required?

sodium hydroxide

11

In the chemical test when testing for aluminium, calcium and magnesium, what is the positive result?

if a white precipitate is formed, it means that it could be Al, Cl, or Mg but if when more is added it dissolves, its Al

12

In the chemical test when testing for chloride, bromide, iodide, what chemicals or conditions are required?

silver nitrate solution and dilute nitric acid

13

In the chemical test when testing for chloride, bromide, iodide, what is the positive result?

Cl- =white precipitate
Br-=cream precipitate
I-=yellow precipitate

14

In the chemical test when testing for carbonate ions what chemicals or conditions are required?

Dilute hydrochloric acid and bubble any gas produced through limewater

15

In the chemical test when testing for carbonate ions, what is the positive result?

limewater turns cloudy

16

In the chemical test when testing for iron (ii) iron (iii) and copper (ii), what chemicals or conditions are required?

add sodium hydroxide

17

In the chemical test when testing for iron (ii) iron (iii) and copper (ii), what is the positive result?

Fe2+ = green precipitate
Fe3+ = brown precipitate
Cu2+ = blue precipitate

18

In the chemical test when testing for lithium, sodium, barium, potassium and calcium what chemicals or conditions are required?

Add sample to roaring flame

19

In the chemical test when testing for lithium, sodium, barium, potassium and calcium what is the positive result?

lithium = crimson
sodium = yellow
barium = green
potassium = lilac
calcium = red

20

In the chemical test when testing for sulphate,what chemicals or conditions are required?

Add dilute hydrochloric acid and barium chloride

21

In the chemical test when testing for sulphate, what is the positive result?

White precipitate

22

What are the rules of equilibria: (le chatlier's principal)

1. high temperature favours endothermic reaction
2. low temperatures favours the exothermic reaction
3. increasing reactants favours forwards reaction
4. decreasing products favours forward reaction
5. high pressure favours side with fewest moles
6. low pressure favours side with most moles

23

How do you work out the overall enthalpy/energy change for the reaction?

Sum (bonds broken) - sum(bonds made) = energy change

24

What are the ideal conditions for the haber reaction?

Low temperature
High pressure
Constant supply of Ne and H2
Remove the products

25

So why are the conditions of the equilibria reaction 450 degrees and 200 atms?

450 is a compromise between the yield of the reaction and the rate of reaction
200 atms is used as extremely high pressures could explode

26

What is dynamic equilibrium?

Most reactions are reversible to some degree
If a system is in dynamic equilibrium then the rate of the forward reaction is the same as the rate of the reverse reaction
This means the concentrations of reactions and products do not change

27

How is ammonia made

Haber process

28

What is the molecular formula of methanoic acid?

HCOOH

29

What is the molecular formula of ethanoic acid?

CH3COOH

30

What is the molecular formula of propanoic acid?

CH3CH2COOH