Chapter 2b Flashcards Preview

Chemistry > Chapter 2b > Flashcards

Flashcards in Chapter 2b Deck (38)
Loading flashcards...
1

What is the formula for rate of a reaction?

Amount of reactant used/ amount of product formed
________________________________________________________
Time

2

State the different ways used to measure rates of reaction

Precipitation
Change in mass
Volume of gas given off

3

Explain collision theory with regards to increasing temperature

When the temperature is increased the particles all moe quicker, if they're moving quicker they're going. To collide more often

4

Explain collision theory with regards to higher concentration

If a solution is made more concentrated it means there are more particles of he reactant which makes collisions between important particles more likely

5

Explain collision theory with regards to larger surface area

If one of the reactants is a solid hen breaking it up into smaller pieces will increase the total surface area if the particles have more area to work on there will be more frequent collisions

6

Define activation energy

The minimum amount of energy needed for the particles to react (reactions only happen if the particles collide with enough energy

7

What is a catalyst?

A substance that speeds up a reaction without being changed or used up in the reaction

8

How are catalysts useful in industry?

- because the reaction is quicker it saves money
- allows the reaction to work at lower temperatures which reduces the energy used in a reaction
Can be used over and over again

9

State some disadvantages of catalysts

Expensive to buy
Different reactions use different catalysts
Catalysts can be 'poisoned' by impurities so they can stop working
Reaction must be kept clean

10

What happens in exothermic reactions?

Heat is given out to the surroundings they warm up
E.g combustion, hand warmers and self heating cans

11

What happens in endothermic reactions ?

Heat is taken in by the surroundings, they become cold
E.g thermal decomposition and sports injury packs

12

Define anhydrous

Without water

13

What pH do acids have?

What colour do they turn?

pH 0-6

Red-orange-yellow

14

What pH do alkalis have?

pH 8-14

Blue- purple

15

What pH is neutral?

pH 7

Green

16

Describe the properties of an acid

pH less than 7
Form h+ ions in water

17

Describe the properties of alkalis

A base that dissolves in water
Form OH- ions in water

18

Acid + base =
H+ + OH-

Acid + base ---->Salt + water
H+ + OH- ----> H2O

19

What is the state symbol of
a) a solid
b) a liquid
c) a gas
d) aqueous

s
l
g
aq

20

Acid + metal =

Metal salt + hydrogen

21

What kind of salts would hydrochloride acid produce

Chloride salts

22

What kind off salts would sulfuric acid produce?

Sulfate salts

23

Acid + metal oxide=

Salt + water

24

Acid + metal hydroxide =

Salt + water

25

Hydrochloric acid + copper oxide=

Copper chloride + water

26

Nitric acid + potassium hydroxide =

Potassium nitrate + water

27

What four things does the rate of reaction depend on?

Temperature
Concentration
Catalyst
Surface area

28

Define electrolysis?

Splitting up using electricity
(If you pass an electric current through an ionic substance that's molten or in a solution it breaks down into the element it's made of)

29

Describe electrolysis

- it requires a liquid (electrolyte) to conduct electricity
- electrolytes contain free ions which allows electricity
- flow of electrons is needed ( electrons taken away at the positive electrode and given at the negative electrode)

30

Describe electrolysis of lead bromide

-At the negative electrode one lead ion accepts two electrons to become one lead atom
-at the positive electrode two bromide ions loose one electron each and becomes one bromine molecules