The rate and extent of chemical change-paper 2

Question 1

What is the rate of chemical reaction?
One slow and fast reaction?

Answer 1

1)how fast the reactants are changed into products.
2)slowest is the: rusting of iron, Burning=fast reaction

Question 2

1)Speed of reaction is?
2)Steeper the line means, when does the line become flat?
3)What does the quickest reaction mean?

Answer 2

1)recording the amount of product formed amount of reactant used up over time.
2)steeper the line= faster rate reaction. line less steep as reactants are used up.
3)quickest reactions=steepest lines, flat in the least time.

Question 3

The rate of a chemical reaction depends on WHAT AND WHY?
Explain the activation energy?

Answer 3

WHAT:
collision frequency of reacting particles more collision=faster the reaction is.
WHY:
energy transferred during a collision. Particles collide enough energy collision to be successful.
ACTIVATION ENERGY:
minimum amount of energy that particles need to react break bonds in the reactant

Question 4

The Rate of Reaction Depends on Four Things?

Answer 4

1) Temperature.
2) concentration solution/pressure of gas.
3) Surface area
4) presence of a catalyst.

Question 5

How does Increasing the Temperature Increases the Rate? 3

Answer 5

1)temperature is increased=particles all move faster.
2)collide more frequently= more energy collisions/sucessful ones
3)enough energy to make the reaction happen= activation energy

Question 6

How does Increasing the Concentration or Pressure Increases the Rate? 3

Answer 6

1)concentrated, more particles knocking about same volume.
2)pressure of a gas is increased=same number particles occupies smaller space.
3)collisions between the reactant particles more frequent.

Question 7

How does Increasing the Surface Area Increases the Rate?

Answer 7

1)reactants is a solid, breaking it up into smaller pieces increase SA:V
2)same volume of the solid, particles around it have more area=collisions more frequently.

Question 8

How does Using a Catalyst Increases the Rate?

Answer 8

1)speeds up a reaction, without being used up in the reaction itself.
2)decreasing activation energy needed reaction to occur. providing an alternative reaction pathway with a lower activation energy.

Question 9

1)Measure the Rate of a Reaction and the equation?
2)Units for gas, solid, time?
Equation for rate of reaction?

Answer 9

1)observed how quickly the reactants are used up, how quickly products formed:
2)product/ reactant gas measure amount in cm3 .solid= grams (g). Time seconds (s).

Question 10

What are the 2 ways to record Precipitation and Colour Change?
What are the 2 negative?

Answer 10

1)record the visual change in a reaction
2)observe a mark through the solution long it takes disappear

-subjective
-can’t plot a rate of reaction graph from the results.

Question 11

1 method Change in Mass (Usually Gas Given Off), a negative and a positive?

Answer 11

1) produces a gas mass balance. Gas released, mass disappearing measured on the balance.
2)quicker reading balance drops, faster reaction= measurements regular intervals, plot graph=find rate.

-accurate
-releasing gas into the room.

Question 12

1 method Volume of Gas Given Off, 1 negative 1 positive?

Answer 12

1) gas syringe measure volume gas given =more gas given off during a time faster
2)regular intervals, plot graph

.volumes accurate nearest cm
-reaction too vigorous, blow plunger out

Question 13

How to Magnesium and HCI React to Produce H, Gas METHOD 5 and RESULT 1?

Answer 13

1) 50cm3 dilute hydrochloric acid conical flask with a gas syringe and a plug
2) add magnesium ribbon to the acid start stopwatch
3) Every 10 seconds, record the volume of gas produced.
4) Plot the results in a table
5) Repeat more concentrated acid solutions.
higher conc=faster rate of reaction

Question 14

How to Sodium Thiosulfate and HCL Produce a Cloudy Precipitate METHOD? 5

Answer 14

1) temperature: 20
50 cm3 dilute sodium thiosulfate to a conical flask.
2) Place flask piece of paper black cross drawn on it.
3)Add 10 cm3 dilute HCI to flask, start stopwatch and record temperature
4) cross disappear through cloudy sulfur, time how long it takes to go.
5) repeated solutions reactant at different starting temperatures

Question 15

How to Calculate the Mean Reaction Rate from a Graph? 2

Answer 15

1) rate reaction graph= amount product formed amount reactant used y-axis, time on the x-axis.
2) mean rate whole reaction= overall change in the y-value divide total time taken for reaction.

Question 16

How to find Reaction Rate at a Particular Point? 2

Answer 16

1)draw a tangent to the curve - a straight line that touches the curve at one point and doesn’t cross it.
2) Gradient= change in y/change in x)

Question 17

Why will Reversible Reactions Reach Equilibrium+process? 5

Answer 17

1)reactants react, concentrations fall forward reaction slow down.
2)more products made concentrations rise, backward reaction will speed up.
3) forward reaction same rate as backward one =equilibrium
4)reversible reaction in a ‘closed system’. none escape and nothing can get in.

Question 18

What is a dynamic equilibrium? 2

Answer 18

1.both reactions still happening, no overall effect.
2.concentrations reactants and products reached balance won’t change.

Question 19

What does the position of equilibrium depend on? 3

Answer 19

.temperature
.pressure (only gases).
.concentration of the reactants and products

Question 20

Can Reversible Reactions Be Endothermic and Exothermic (thermal decomposition)? 2

Answer 20

1) reversible reactions=reaction endothermic one direction, exothermic other
2) energy transferred from surroundings endothermic reaction=energy transferred to surroundings in exothermic reaction= Thermal decomposition.

Question 21

What is le Chateliers principle?
What is it used for?

Answer 21

1) Le Chatelier’s Principle= change conditions reversible reaction at equilibrium, counteract that change.
2) used predict the effect of any changes you make to a reaction system.

Question 22

Changes to the Temperature and how does equilibrium respond? 2

Answer 22

1) decrease temperature=equilibrium move exothermic direction produce more heat + reactant or product
2) raise temperature=equilibrium move in endothermic direction to try to decrease it.

Question 23

Changes to the Pressure and how does equilibrium respond, how do you know which side has more? 3 (gases)

Answer 23

1) increase pressure, equilibrium reduce it move direction fewer molecules of gas.
2) decrease the pressure, equilibrium increase it move direction of more molecules of gas.

-balanced symbol equation see which side more molecules of gas

Question 24

Changes to Concentration and how does equilibrium respond? 3

Answer 24

1) change concentration= not equilibrium.
2) increase concentration reactants decrease it by making more products.
3) decrease the concentration of products increase it by reducing amount reactants.

Question 25

Why can the Position of Equilibrium Can be on the Right or the Left? 2

Answer 25

1)reaction’s equilibrium amounts of reactants and products not equal.
2) equilibrium lies to the right= concentration of products is greater than that of the reactants

Question 26

Temperature water boils at?

Answer 26

100c