Question

Reaction: H₂O + C₃H₇Br --- >  C₃H₇OH + HBr

Table 1.0

Reaction Trial	Grams of H2O	Grams of C3H7Br	Temperature of °C	Reaction speed
1	10	10	30	2.0
2	20	20	30	4.0
3	40	20	30	4.0
4	40	20	60	10.0

A. What is the relationship between grams of H₂O and reaction speed?

B. What is the relationship between grams of C₃H₇Br and reaction speed?

C. What is the relationship between temperature and reaction speed?

D. Write two hypotheses based on your answers in A and C.

Table 1.1

Reaction Number	Grams of H2O	Grams of C3H7Br	Temperature of °C	Reactions speed
5	40	20	15	?

E1. Refer to Table 1.1: If the amounts of H₂O, C₃H₇Br B remain unchanged but the temperature is decreased to 15°C, how would you expect the reactions speed to change?

E2. Based on the data in Table 1.0, explain your above answer. (Use a reasonable numerical value for the reactions speed)

Table 1.2

Reaction Number	Grams of H2O	Grams of C3H7Br	Temperature of °C	Reactions speed
6	80	20	30	?

F1. Refer to Table 1.2:  If the amount of H₂O increases to 80 grams but the amount of C₃H₇Br remains unchanged and the temperature is kept at 30°C, how would you expect the reactions speed to change?

F2. Based on the data in Table 1.0, explain your above answer. (Use a reasonable numerical value of the reactions speed)

RUBERIC

For question A: Make sure the answer contains reactions speed not related to grams of H₂O

For question B: Make sure answer contains reaction speed increases or decreases with grams of C₃H₇Br

For C: Answer contains reaction speed increases or decreases with Temperature of °C

For D1: Make sure hypothesis includes relationship between amount and reaction speed

For D2: Make sure hypothesis includes relationship between temperature and reaction speed

For E1: Answer has to include "speed decreases" with the use to hypothesis D2 to justify answer

For E2: Numerical value has to be less than 4

For F1: Make sure the answer include "no change" and hypothesis D1 was used to justify answer.

For F2: Is the numerical value 4?

Answer 1

A. The speed of reaction has no relationship with amount of water present in the reaction as we can see that the rate of reaction has not changed even though the no of grams of water read doubled in reaction 3.

B. The speed of reaction is proportional to the amount of C3H7Br present in the reaction as we can see from the reaction 2 that the rate of reaction has doubled with the amount of C3H7Br.

C. The rate of reaction has increased five fold as the temperature has been doubled. Therefore the speed of reaction is proportional to the temperature.

D. i) The rate of reaction is zero order with respect to H2O.

ii) The reaction must be endothermic as the reaction rate has increased five fold as the temperature got doubled.

E1. The speed of reaction would get decreased by five times or the speed of reaction becomes one fifth of the original speed( refer to the second hypothesis)

E2. The speed of reaction would be same as reaction 1 as the reaction is zero order with respect to H2O that is the speed of reaction would be 2.

F1. The rate of reaction is zero order with respect to H2O therefore the speed of reaction remains unchanged.

F2. As we have seen in reaction 3 that increasing the amount of H2O present would not effect the speed of reaction.