Core inorganic and physical chemistry for forensic science Flashcards

1
Q

What does the state in which a substance exist depend upon?

A

The competition or balance between intermolecular forces and thermal energy

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

What is the equation for pressure?

A

Force/area

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

What is mechanical equilibrium?

A

Equality of pressure

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

Define diathermic

A

Thermally conducting

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

Define adiabatic

A

Thermally insulating

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

Define thermal equilibrium

A

No change of state occurs when two object are in contact through a diathermic boundary

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

Zeroth Law of Thermodynamics

A

If A is in thermal equilibrium with B, and A is in thermal equilibrium with C, then C is also in thermal equilibrium with B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Charles’ Law

A

At a constant pressure, the volume of a fixed mass of gas is proportional to its pressure

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

Boyle’s Law

A

Provided temperature is kept constant, the volume of a fixed mass of gas is inversely proportional to its pressure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Law of combining volumes (Gay-Lussac)

A

At any given p and T, the volumes of gases that react with one another are in the ratios of small whole numbers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Avogadro’s hypothesis

A

equal volumes of gases at the same p and T contain an equal number of molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Avogadro’s Law

A

volume of a gas maintained at a constant pressure and temperature is directly proportional to the number of moles in the gas

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

what assumptions were made about the ideal gas law

A

there are no intermolecular forces in the gas, and gas molecules have no volume

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

what is the critical point

A

a set of conditions under which a liquid and its vapour become identical

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

system

A

part of the world in which we have special interest

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

surroundings

A

region outside the system where we make our measurements

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

what is work defined as

A

motion over some distance against an opposing force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the equation for work when pressure is constant

A

-P x change in V

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Name the 3 ways the energy of a system may be changed other than work itself

A

heat (energy change results from a temperature difference between system and surroundings), exothermic process, endothermic process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the difference between endothermic and exothermic

A

exothermic is when energy is transferred as heat to the surroundings, endothermic is when energy is acquired from its environment as heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

define internal energy (U)

A

total energy of a system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

define the first law of thermodynamics

A

the change in energy of a system is equal to the sum of the work done on the system and heat put into the system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the equation for the change in U

A

q + w

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

define calorimerty

A

study of heat transfer during physical and chemical processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
define calorimeter
device for measuring energy transferred as heat
26
define adiabatic process
transfer of energy in the form of work only
27
define thermochemistry
the study of energy transferred as heat during the course of chemical reactions
28
what is the enthalpy change for an exothermic reaction
< 0, negative
29
define standard enthalpy change
the change in enthalpy for a process in which the initial and final substances are in their standard states
30
define standard enthalpy of transition
the standard enthalpy change that accompanies a change of physical state
31
define the standard enthalpy of sublimation
a change in enthalpy independent of the path between two states
32
define Hess's law
the overall enthalpy change of a reaction is independent regardless of the route taken
33
define standard enthalpy of formation
the enthalpy change to form a compound from its elements under standard conditions with all products and reactants in their standard states
34
define mean bond enthalpy
the average enthalpy change associated with the breaking of a specific bond
35
define Kirchoff's Law
standard reaction enthalpies at different temperatures can be calculated from the heat capacities at constant pressure
36
define spontaneous reactions
those that, once started, will continue without any outside intervention
37
define the second law of thermodynamics
the state of entropy of the entire universe, as an isolated system, will always increase over time
38
Define the third law of thermodynamics
the entropy of a pure crystalline substance at absolute zero is zero
39
If G<0...
the reaction is spontaneous in the forward direction
40
If G=0...
the reaction is at equilibrium
41
If G>0...
the reaction is non-spontaneous in the forward direction but the reverse direction is spontaneous
42
name the 4 factors which affect reaction states
physical state of reactions, reactant concentrations, reaction temperature, the presence of a catalyst
43
define chemical rate
the change in the concentration of reactants or products per unit of time
44
define reaction rate
either the rate of the disappearance of A or the rate of the appearance of B
45
equation for rate
concentration/time
46
what are the four 'rules' for collision theory
particles must collide before reaction, not all collisions lead to reactions, reactions must have an activation energy, for the reaction to occur the molecules must collide at a specific orientation
47
define steric hinderance
when molecules are large so it is harder for them to collide at the correct orientation
48
what are the 4 factors rate of reaction can be increased by
increasing surface area, increasing concentration, increasing temperature, using a catalyst
49
define first order
when the rate doubles, the concentration doubles
50
define second order
when the concentration doubles, the rate quadruples. It is the square of what happens to the concentration
51
define half-life
the time required for the concentration of a reactant to react half of its initial value
52
define heterolysis
one of the atoms gains both electrons and becomes negatively charged
53
define homolysis
each atom keeps one of the bonding pairs of electrons, forming free radicals
54
define rate determining step
slowest step which limits the overall reaction rate
55
define the effective nuclear charge (Zeff)
the amount of positive charge experienced by an electron from the nucleus
56
what is the equation for Zeff
Z-S, where Z is the nuclear charge and S is the shielding constant
57
describe the trends of effective nuclear charge
increases across a period as protons are added to the nucleus, and increases down a group as the increase in protons is offset by the increased number of shielding electrons
58
describe the trends in orbital energies
increase down a group as they increase with the value of n, and decrease across a period because n remains unchanged and Zeff dominates
59
describe the trends in atomic size
decreases across a period due to increasing Zeff, and increases down a group as orbitals with a higher n have larger radii
60
define ionisation energy
the energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions
61
describe the trends in ionisation energy
increases across a period due to increasing Zeff, and decreases down a group as there is lower nuclear attraction
62
define electron affinity
the energy required to add an electron to each atom in one mole of gaseous atoms to form one mole of 1- ions
63
describe the trends in electronegativity
decreases down a group as atomic radius and shielding are increasing, and increases across a period due to an increase in nuclear charge and a decrease in atomic radius
64
define electronegativity
measure of the tendency of an atom to attract a bonding pair of electrons
65
define redox reaction
process of electrons being transferred between species, both oxidation and reduction occur
66
define reducing agent
species which donates electrons, the species itself is oxidised
67