Chapter 16 - speed of reactions Flashcards

1
Q

what are the four factors that affect the speed of reactions

A
  • particle size
  • temperature
  • concentration
  • pressure
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2
Q

explanation for higher speed of reaction - particle size

A

smaller particle size means larger total surface area. Therefore reactants particles have increased frequency of effective collisions resulting in higher speed of reaction

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3
Q

explanation for higher speed of reaction - temperature

A

at higher temperature particles have more average kinetic energy and they move more vigorously. Therefore reactant particles have increased frequency of effective collisions resulting in higher speed of reaction

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4
Q

explanation for higher speed of reaction - concentration

A

at higher concentration reactants have more particles per unit volume . Therefore reactant particles have increased frequency of effective collisions , resulting in higher speed of reaction.

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5
Q

explanation for higher speed of reaction - pressure

A

at higher pressure there is decreased volume and cause particles to be forced closer together. therefore reactant particles have increased frequency of effective collisions resulting in higher speed of reaction

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6
Q

what are the two ways to measure speed of reaction

A
  • collecting volume of gas produced
  • measuring the mass of reactants after reaction
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7
Q

formula to calculate the speed of reaction in set up one (volume of gaseous product)

A

speed of reaction = increase in volume of gas produced divided by time taken

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8
Q

formula to calculate the speed of reaction in set up two (mass of reactants)

A

seed of reaction = decrease in mass of reactant mixture divided by the time taken

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9
Q

graph facts according to the gradient

A

steeper gradient faster speed of reaction

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10
Q

graph facts according to y axis

A

greater difference in y axis reading means increase in volume of gaseous product or increase in gaseous product lost

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11
Q

how to describe a graph for reaction of the first set up (volume of gaseous product)

A
  • as the reaction begins the gradient is steepest as it is the highest rate of reaction / highest speed of reaction
  • as reaction proceeds there is a less steep gradient and rate of reaction / speed of reaction decreases
  • as reaction s=comes to a stop there is no gradient and only flat line
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12
Q

how to describe a graph for reaction of the second set up (mass of reactants)

A
  • as reaction begins the amount of reactant particles are at the maximum causing the highest rate/ speed of reaction therefore there is the steepest gradient
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13
Q

explain using colliding particles why rate of reaction decreases as experiment slows

A

both reactant X and Y are being used up in reaction so there is lesser particles of reactant X and Y causing the reactant particles to have decreased frequency of effective collisions causing a lower rate/ speed of reaction

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14
Q

Zn reacts with sulfuric acid, why does the reaction stop

A

all the Zn have reacted with the sulfuric acid and is all used up

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15
Q

Zn reacts with excess sulfuric acid state one observation to indicate that he reaction has stopped

A

no more effervescence will be observed

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16
Q

Zn reacts with excess sulfuric acid, why is there a loss of mass after the reaction

A

hydrogen gas was produced and escaped to the surroundings

17
Q

given a volume-time graph explain the rate of change as the experiment progresses

A
  • steepest part is the highest rate of reaction because there are more particles available to react in the beginning
    -less steep gradient means the rate of reaction is getting slower as more reactant particles have been used up as reaction progresses. lesser particles left to react therefore slower rate of reaction
  • no gradient = no reaction = reaction complete