Test 2 - rates of reaction and organic chemistry

Question 1

What is the rate of a reaction?

Answer 1

how fast the reactants are changed into products

Question 2

What is an example of a slow reaction?

Answer 2

rusting of iron

Question 3

Give an example of a moderate reaction?

Answer 3

metal magnesium reacting with an acid

Question 4

Give an example of a fast reaction?

Answer 4

burning, explosions

Question 5

How do you find speed of a reaction?

Answer 5

recording amount of product formed or amount of product used up

Question 6

What does a steep line on the graph show?

Answer 6

fast reaction

Question 7

What does the rate of a reaction depend on?

Answer 7

• collision frequency of particles (more collisions, faster reaction)
• energy transferred in reaction

Question 8

What is activation energy?

Answer 8

the minimum amount of energy that particles need to react

Question 9

Why do particles have to overcome activation energy?

Answer 9

break the bonds in the reactants and start the reaction

Question 10

What four things does the rate of reaction depend on?

Answer 10

• temperature
• concentration
• surface area
• catalyst

Question 11

Explain how increasing temp increases rate of reaction?

Answer 11

• temp increased and particles move faster, more collisions
• higher temp also means higher energy of collisions
• more succesfull collisions, more particles coliding with enough energy

Question 12

Explain why increasing surface area increases ROR?

Answer 12

• more particles will be exposed compared to volume
• particles around will have more area to work, frequency increases
• increase ROR

Question 13

Explain why increasing concentration increases ROR?

Answer 13

• more particles of reactant in same volume, collisions more likely - faster reaction

Question 14

What is an exothermic reaction?

Answer 14

gives out energy to the surroundings resulting in temperature rise of surroundings

Question 15

What is an endothermic reaction?

Answer 15

takes in energy from from surrroundings resulitng in temperature decrease in suroundings

Question 16

WHat is enthalpy change?

Answer 16

overall change in energy in a reaction

Question 17

Whta is a catalyst?

Answer 17

a substance which increases the rate of reaction without being chemically used up or changed in a reaction, usually finding an alternate pathway

Question 18

Why do catalysts work?

Answer 18

• lower the activation energy

- more particles have minimum amount of energy needed for reaction to occur when particles collide

Question 19

rate of reaction equation?

Answer 19

amount of reactant used or amount of product formed / time

Question 20

What are the names of the three rates of reaction experiments?

Answer 20

• precipitation
• change in mass
• volume of gas given off

Question 21

Describe the precipitation experiment?

Answer 21

• two see through solutions produce precipitate
• mix reactants in chronicle flask over cross on paper
• time how long it takes for cross to disappear

Question 22

Describe change in mass experiment?

Answer 22

• as gas released, mass decreases

- time how long for balance to stop changing

Question 23

Describe the volume of gas given off experiment?

Answer 23

• use gas syringe to collect gas

- time how long till gas syringe stops

Question 24

How can you measure how surface area effects rate?

Answer 24

look in book for experiment

Question 25

What is a reversible reaction?

Answer 25

where the products of the reaction can react with each other and convert back to the original reactants

Question 26

Give an example of a reversible reaction?

Answer 26

thermal decomposition of ammonium chloride

Question 27

Explain why thermal decomposition of ammonium chloride is a reversible reaction?

Answer 27

- ammonium chloride is a white solid so when heated it breaks down into ammonia and hydrogen chloride - of let cool the ammonia and hydrogen chloride react to re-form solid

Question 28

What is a general formula?

Answer 28

- algebraic formula that can describe any member of a family of compounds

Question 29

What is an empirical formula?

Answer 29

simplest whole number ratio of atoms in compound

Question 30

What is a molecular formula?

Answer 30

actual number of atoms of each element

Question 31

What is the displayed formula?

Answer 31

shows how atoms are arranged

Question 32

What is the structural formula?

Answer 32

shows arrangement of atoms carbon by carbon

Question 33

What is a homologous series?

Answer 33

a group of compounds that can be represented by the same general formula

Question 34

What is a functional group?

Answer 34

a group of atoms that determine how a compound typically reacts

Question 35

What are the stem words for number of carbons?

Answer 35

``` meth eth prop but pent hex ```

Question 36

What are isomers?

Answer 36

two or more molecules with the same molecular formulae but differant structural formula

Question 37

What do isomers have?

Answer 37

diffferant physical properties

Question 38

What is a hydrocarbon?

Answer 38

molecules only made of carbon and hydrogen

Question 39

What is crude oil?

Answer 39

mixuture of substances - mostly hydrocarbons

Question 40

How are compounds in crude oil seperated?

Answer 40

fractional distillation

Question 41

What is crude oil seperated in?

Answer 41

fractionating column

Question 42

Where is the hottest part of a fractionating column?

Answer 42

bottom

Question 43

What do longer hydrocarbons have?

Answer 43

high boiling points

Question 44

Where do longer hydrocarbons seperate out?

Answer 44

the bottom

Question 45

What do bubble caps do?

Answer 45

stop seperated liquid from running out down the column and remixing

Question 46

What are the two types of hydrocarbons?

Answer 46

saturated and unsaturated

Question 47

What are saturated hydrocarbons?

Answer 47

only contain single bonds between carbon atoms

Question 48

What are unsaturated hydrocarbons>

Answer 48

have double or triple bonds between carbon atoms

Question 49

What is the order fractions from top to bottom?

Answer 49

- refinery gases - gasoline - kerosene - diesel - fuel oil - bitumen

Question 50

What is cracking?

Answer 50

splitting up long chain hydrocarbons

Question 51

describe long hydrocarbons?

Answer 51

high boiling points and viscous

Question 52

describe shorter hydrocarbons?

Answer 52

lower boiling points are much thinner and paler

Question 53

What is the high demand for (long or short hydrocarbons?

Answer 53

short hydrocarbons

Question 54

What is diesel cracked into?

Answer 54

- petrol - paraffin - ethene for polymers

Question 55

What is cracking a form of?

Answer 55

thermal decomposition

Question 56

What does cracking also produce?

Answer 56

alkenes

Question 57

What are the conditions for cracking?

Answer 57

- passed over powdered catalyst at about 600-700 degrees. alkane is heated until vaporised then breaks down when comes into contact with catalyst producing short chain alkanes and alkenes

Question 58

Which catalysts can be used in cracking?

Answer 58

- silica | - alumina

Question 59

What happens when you burn a fuel?

Answer 59

releases energy in form of heat

Question 60

Why do hydrocarbons make great fuels?

Answer 60

combustion reaction that happens when you burn them in oxygen give out lots of energy

Question 61

hydrocarbon + oxygen = ?

Answer 61

carbon dioxide + water

Question 62

What type of reaction is hydrogen + oxygen?

Answer 62

complete combustion

Question 63

What does incomplete combustion produce?

Answer 63

carbon monoxide + soot + carbon

Question 64

Why does incomplete combustion occur?

Answer 64

not enough oxygen

Question 65

What is the problem with carbon monoxide?

Answer 65

combines to red blood cells and stops blood doing proper job

Question 66

Why is acid rain formed?

Answer 66

- sulfer dioxide | - nitrogen oxides

Question 67

How is sulfer dioxide and nitrogen oxides formed?

Answer 67

when fractions from crude oils are burned

Question 68

Why is sulfer dioxide formed?

Answer 68

comes from sulfer impurities in hydrocarbon fuel

Question 69

How is nitrogen oxides formed?

Answer 69

- when temp is high enough for nitrogen and oxygen react in the air

Question 70

What is made when sulfer dioxide and nitrogen oxides mix with water vapour?

Answer 70

- dilute sulfuric acid and nitric acid

Question 71

What is wrong with acid rain?

Answer 71

causes lakes to become acidic and many plants and animals die as a result

Question 72

What are alkanes?

Answer 72

saturated hydrocarbons

Question 73

What is alkane general formula?

Answer 73

CnH2n+2

Question 74

What are the names of the first five alkanes?

Answer 74

``` methane ethane propane butane pentane ```

Question 75

What do alkanes burn in?

Answer 75

complete combustion reactions

Question 76

What can react with alkanes? to form what?

Answer 76

halogens to form haloalkanes

Question 77

What is needed to make a haloalkane?

Answer 77

ultraviolet light

Question 78

What type of reaction is a haloalkane made?

Answer 78

substitution

Question 79

What is a substitution reaction?

Answer 79

hydrogen atom from alkane is substituted with chlorine or bromine

Question 80

What do alkenes have?

Answer 80

carbon to carbon double bond - unsaturated

Question 81

name the first three alkenes?

Answer 81

ethene propene butene

Question 82

What is the alkene general formula?

Answer 82

CnH2n

Question 83

What can alkenes react with?

Answer 83

halogens

Question 84

What does alkene + halogen make ?

Answer 84

haloalkanes

Question 85

What is the alkene + halogen reaction an example of?

Answer 85

addition reaction

Question 86

How do you test for a alkene?

Answer 86

shake alkene with orange bromine water - solution will become colourless