Reactivity 2 Flashcards

(47 cards)

1
Q

Stoichiometry

A

The fixed relationship between the number of reactant particles and the number of product particles

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2
Q

Formula to find out the number of moles of a gas

A

Volume (V)/molar volume (Vm)

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3
Q

Molar volume definition

A

The volume occupied by one mole of any gas

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4
Q

Limiting reactant/reagent

A

The reactant that is in excess, i.e runs out first

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5
Q

Theoretical yield definition

A

Maximum amount of product that could be formed according to the balanced equation

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6
Q

Experimental yield definition

A

Actual amount of product obtained when the experiment is performed

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7
Q

Percentage yield formula

A

Experimental yield/theoretical yield x 100

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8
Q

Factors that could cause the experimental yield to be lower than the theoretical yield

A
  • Side reactions occurring
  • Decomposition of reactants and/or products
  • Loss of product during purification
  • Reversible chemical reactions preventing process completion
  • Incomplete reaction
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9
Q

Factors that could cause the experimental yield to be higher than the theoretical yield

A
  • Impurities in a product
  • When a product hasn’t been fully dried
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10
Q

How to find atom economy (4 steps)

A
  • Write balanced equation
  • Calculate relative molar mass, and then total mass
  • Calculate relative molar mass of each desired product, and then total mass of each desired product formed
  • Find atom economy using atom economy formula
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11
Q

Atom economy formula

A

Total mass of desired products/total mass of products x 100

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12
Q

If a use for the products are found in atom economy, what is the atom economy?

A

100%

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13
Q

Units for rate of reaction

A

mol dm^-3 s^-1

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14
Q

Collision theory

A

Particles must collide at the right angle with sufficient energy

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15
Q

How does concentration increase rate of reaction?

A

More collisions will occur due to the greater number of particles in the acid

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16
Q

How does surface area increase rate of reaction?

A

Only the particles on the surface can collide, if it is in powdered form there is a much greater surface area; more collisions per second

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17
Q

How does temperature increase rate of reaction?

A

The particles are moving faster; there will be more collisions per second

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18
Q

How does a catalyst increase rate of reaction?

A

Bringing the reactive parts of the reactants into close contact with each other, lowering the activation energy; less energy will be needed to collide sufficiently

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19
Q

Formula for rate of reaction

A

increase in product concentration/time taken or (-)decrease in product concentration/time taken
rise over run

20
Q

Is rate positive or negative

21
Q

Systematic errors

A

Inaccurate measurements
When all measurements are higher or lower than expected values
Cannot be fixed

22
Q

Random errors

A

Imprecise data
Occur due to limitations in measurement equipment (uncertainties), misinterpreted measurements or not enough trials.
Can be fixed by repeating measurements and averaging results

23
Q

Equilibrium law

A

When the rate of the forward reaction is equal to that of the reverse reaction.

24
Q

Formula for K

A

[products]/[reactants]

25
If it were a reverse reaction, how would K be written?
K'
26
What is K dependent on?
Temperature
27
If K is big, what happened with the reaction and concentration?
The reaction is pretty much completed and the concentration of reactants is very small.
28
If K is small, what happened with the reaction and concentration?
The reaction has barely taken place and the concentration of the products is very small.
29
If K is around one, what happened with the equilibrium?
There will be a good amount of reactants and products in the equilibrium.
30
Units of K
K has no units
31
How to find K from K'
Reciprocal
32
If you add a catalyst to a reaction, what happens to the equilibrium?
Nothing
33
If the concentration of the products is increased, what happens to the equilibrium?
Shifts to the left
34
If the concentration of the reactants decreases, what happens to the equilibrium?
Shifts to the left
35
If the concentration of the products decreases, what happens to the equilibrium?
Shifts to the right
36
If the concentration of the reactants increases, what happens to the equilibrium?
Shifts to the right
37
If the number of mols (gas) on both sides are equal, what happens to the equilibrium?
Nothing
38
If there are more mols on the reactant side, what happens to the equilibrium?
Shifts to the right
39
If there are more mols on the product side, what happens to the equilibrium?
Shifts to the left
40
In exothermic reactions, lowering the temperature will do what to the equilibrium?
Shift to the right
41
In endothermic reactions, increasing the temperature will do what to the equilibrium?
Shift to the right
42
In exothermic reactions, the higher the temperature gets does what to the value of K?
It decreases the higher the temperature
43
In endothermic reactions, the higher the temperature gets does what to the value of K?
It increases the higher the temperature
44
What thing changes the K value?
Temperature
45
Heterogenous equilibria
When one or more of the reactants are in different phases.
46
How to calculate theoretical yield
Use mole ratios- perhaps with figures given in the question
47
If asked a question to calculate something measured at STP, how do you find it?
Multiply the 'n' value by 22.7 (STP value)