module 3 Flashcards

1
Q

what are the two types of changes

A
  • physical: does not result in the formation of new substances
  • chemical: involves the formation of new substances
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

indicators of a physical reaction

A
  • change in state
  • change in size/shape
    eg. synthesis and decomposition
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

indicators of a chemical change

A
  • production of bubbles that indicates the a gas has been formed
  • production of odour
  • change in temperature
  • formation of a precipitate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are the six types of reactions

A
  • synthesis
  • decomposition
  • combustion (+incomplete)
  • precipitation
  • acid + base
  • acid + carbonate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

synthesis reaction

A

reaction between two or more substances to form a new substance
- two metals –> ionic
- non-metal + metal –> covalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

decomposition

A

where one reactant is broken into two or more constituent substances and requires the input of energy to break bonds
- thermal decomposition
- electrolysis
- photolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

combustion

A
  • burning a substance in oxygen at high temperatures to form new products
  • exothermic
  • complete: fuel + oxygen –> water + carbon dioxide
  • incomplete: fuel + oxygen –> water = carbon dioxide + carbon monoxide + soot (C)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

precipitation

A

mixing two solutions together resulting in the formation of a insoluble solid –> precipitate
- predicted using solubility rules
- nagsag
- care bear stroller

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

acid base (neutralisation)

A
  • acid + base –> salt + water
  • exothermic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

acid carbonate

A
  • acid + carbonate –> salt + water + carbon dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

process of cycads

A
  • cut up fruit and place in mesh bags
  • soaked in water to leach out the toxins
  • heat the fruit which causes thermal decomposition of toxins
  • fruits in the mesh bags are places in a running stream of water to leach out the toxins
  • fermentation to leach out the toxins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

metal and steam

A

hydrogen gas and metal oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

metal and water

A

metal hydroxide and hydrogen gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

metal and oxygen

A

metal oxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

metal and dilute acid

A

salt and hydrogen gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

displacement reactions

A

the more reactive metal displaces the less reactive metal ions from the solution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

atomic radius

A
  • increases across the group and decreases down the period
  • larger atomic radius –> the zeff is lower –> easier to remove electrons –> more reactive
18
Q

ionisation energy

A

energy required to remove one valence electron from an element in the gaseous state
- increases across the period and decreases down the group
- lower first ionisation energy –> easier to remove valence electrons –> more reactive

19
Q

electronegativity

A

strength which atoms in a compound are able to attract shared electrons to itself
- increases across the period and decreases down the group
- lower electronegativity –> does not hold valence electrons well –> easier to remove valence electrons –> more reactive

20
Q

oxidation number/state

A

hypothetical charge of an atom if all bonding was ionic –> degree of oxidation

  1. neutral atoms/one element = 0
  2. overall oxidation state of a compound = 0
  3. ions or polyatomic ions = overall charge
  4. fluorine = -1
  5. hydrogen = +1 (covalent) [-1 in hydrides]
  6. oxygen = -2 in compounds (-1 peroxide)
21
Q

redox reaction

A
  • oxidation and reduction occur
  • oxidation of one or more species has changed
22
Q

oxidation

A
  • increase in oxidation state
  • loss of electrons
  • reducing agent
23
Q

reduction

A
  • decrease in oxidation state
  • gain of electrons
  • oxidising agent
24
Q

table of standard reduction potentials

A

-hardest (non-spontaneous) to reduce to easiest to reduce
- more reactive –> easier to be oxidised –> easier to lose electrons
- the least reactive –> easier to reduce –> don’t tend to lose electrons

25
Q

galvanic cells

A
  • spontaneous redox reaction to create an electrical current
  • transfer from anode to cathode
  • converts chemical energy to electrical energy
  • two half cells that are the site for oxidation and reduction

contains:
- electrode (anode, cathode)
- electrolyte (anolyte, catholyte)
- salt bridge
- electrical leads
- voltmeter

26
Q

electrode

A
  • site where oxidation and reduction occurs
  • made from metal –> electrically conductive
  • anode: oxidation half cell
  • cathode: reduction half cell
27
Q

electrolytes

A
  • facilitate electrical conductivity –> ions as it is aqueous that conducts ions
  • anolyte: oxidation half cell
  • catholyte: reduction half cell
28
Q

salt bridge

A
  • closes the electrical circuit
  • maintains electrical neutrality
29
Q

three types of galvanic cells

A
  • two reacting electrodes
  • non-reacting electrode
  • gaseous redox reaction (one s a gaseous reagent at least)
30
Q

inert electrodes

A
  • graphite
  • lead
31
Q

standard potential of a glavanic cell

A

amount of electricity that can be generated at a standard state
- oxidation (reverse sign) + reduction
- must be positive as it is spontaneous

32
Q

how is a reaction caused

A

successful collision
- sufficient kinetic energy
- successful orientation

33
Q

collision theory

A
  • all molecules move around and collide independently
  • chemical reaction only results from a successful collision

assumptions:
1. molecules are in a spherical shape
2. molecules travel through the air in a linear fashion
3. collision only occurs between two molecules
4. either a successful or unsuccessful collision

34
Q

rate of reaction

A

measure of how quickly the reactants are being consumed or products are being formed

  • change in concentration of products over time
    rate of reaction = frequency of collisions times success rate of collisions
35
Q

maxwell boltzmann distribution

A

describes the molecular distribution of kinetic energy in any sample of matter at a particular temperature
- y axis: number of particles
- x axis: kinetic energy (J)

36
Q

activation energy

A

minimum energy that a molecule must possess in order for it to undergo a successful collision (chemical reaction)
- difference in reactants and peak of curve (energy profile diagrams)

37
Q

surface area (maxwell boltzmann)

A
  • increases particles
  • increased collisions
  • increased rate of reaction (success rate does not change)
  • shifts up
38
Q

concentration (maxwell boltzmann)

A
  • only the concentration of aqueous or gaseous species can be increased
  • increased number of collisions
  • increased rate of reaction (success rate does not change)
  • shifts up
39
Q

temperature (maxwell boltzmann)

A
  • shifts peak to the right (average kinetic area has increased)
  • area under the curve must be constant (number of particles has not changed –> gets lower)
  • increases reaction rate and total frequency of collisions
40
Q

catalyst (maxwell boltzmann)

A
  • decreases activation energy
  • increases rate of reaction
  • increases success rate of collisions
41
Q

catalyst

A

non reagent that increases the reaction rate of a substance by providing and alternate pathway that lowers the activation energy

42
Q

energy profile diagrams

A

show the change in internal energy over the course of a reaction
- exo: reactants > products (energy is released)
- endo: reactants < products (energy is absorbed)
- activation energy –> difference in reaction and peak of curve
- only the catalysts changes the energy profile diagram –> decreases the activation energy as it provides an alternate pathway