C6 - chemical reactions (changes, rate of reactions, redox) Flashcards

1
Q

what affects rates of reactions

A

-temp
-concentration
-pressure of gas
-Surface area of solids
-catalysts

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2
Q

define successful collision

A

-collisions with enough energy to react

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3
Q

ways to measure rate of reaction

A

-loss of mass
-volume of gas produced

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4
Q

things needed for a reaction

A

particles need to collide with enough energy to start a reaction

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5
Q

how to write a conclusion

A

-describe results
-explain - why

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6
Q

define anomaly

A

resultthat doesnt fit the pattern

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7
Q

conclusion for temp.

A

-more kinetic energy
-more movement
-more frequent
-more successful collision
-faster rate of reaction

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8
Q

why does rate of reaction decrease after 50%

A

-there are less reactant particles

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9
Q

formula for average rate of reaction

A

-total mass lost/ time

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10
Q

how to find rate of reaction on graph

A

-make a tangent
-draw lines extending from tangent - make a triangle
-find gradient
-ans can vary

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11
Q

sodium thiosulfate + hydrochloric acid ->

A

-sodium chloride + water + sulfur dioxide + sulfur
-sulfur is a precipitate which makes solution cloudy

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12
Q

does concentration affect activation energy

A

no

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13
Q

how to increase concentration

A

-increase no. particles
-decrease volume

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14
Q

conclusion for concentration/ pressure

A

-more concentration
-more particles per unit volume
-more frequent collisions
-increased rate of reaction
NO ENERGY CHANGE

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15
Q

define limiting reactant

A

reactant that is used up first in a reaction

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16
Q

relationship of Surface area & particle size

A

-more surface area
-smaller particle size

17
Q

conclusion of surface area

A

-smaller particle size
-more surface area exposed to react
-more frequent collisions
-increased rate of reactions
NO ENERGY CHANGE

18
Q

define activation energy

A

The minimum energy colliding particles require to react

19
Q

define catalyst

A

-substance that speeds up the rate of a reaction but is unchanged at the end of the reaction

20
Q

what does catalyst do to activation energy

A

-lower activation energy

21
Q

conclusion of catalysts

A

-increase rate of reaction
-by lowering activation energy
-by providing an alternative reaction pathway
-more successful collisions - greater proportion of particles with energy above the activation energy

22
Q

more successful collisions or more frequent collisions

A

-temp = more frequent & successful collisions
-concentration = more frequent collisions
-surface area = more frequent collisions
-catalyst = more successful collisions

23
Q

note: oxidation & reduction always go tgt

A
24
Q

diff. in numbering of oxidation state & ionic

A

oxidation state - +2
ionic - 2+

25
Q

reduction things

A

-loss of oxygen
-gain of electrons
-gain of hydrogen
-oxidising agent

26
Q

oxidation things

A

-gain of oxygen
-loss of electrons
-loss of hydrogen
-reducing agent

27
Q

define spectator ion

A

-ion that doesn’t change in a reaction

28
Q

OILRIG

A

-Oxidation Is Loss of electrons
-Reduction Is Gain of electrons

29
Q

ionic half equations

A

-find oxidising & reducing agents
Reactants -> Prodcuts
- _a__ -> ___ + ____e (a is oxidised)
- _a__ + ____e -> _____ (a is reduced)
-electrons in both are the same

30
Q

rules:

A

-all elements oxidation state = 0 - electrically neutral
-rmb charges for some compounds - eg, SO4 = -2
-H oxidation state = +1
-O2 oxidation state = -2
-a compound oxidation state total = 0

30
Q

ionic equations

A

-rewrite half equations
-cancel electrons from both sides