CHEM10007 Lecture Notes - Lecture 21: Acid Strength, Signify, Geis

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olivecaribou938

31 Jul 2018

School

University of Melbourne

Department

Chemistry

Course

CHEM10007

Professor

All

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Document Summary

Tells how fast or slow a reaction is, as not all reactions occur at the same speed. Measured by looking at the change in concentration of reactants/products over a period of time. (cid:1870)(cid:1853)(cid:1872)(cid:1857)=(cid:1856)[ ](cid:1856)(cid:1872) =[ ](cid:1872)(cid:2870) [ ](cid:1872)(cid:2869) (cid:1872)(cid:2870) (cid:1872)(cid:2869) Where d=delta=change, [ ] = concentration, and t = time. Average rate the rate measure over a particular time. A rate cannot be negative, but will sometimes have a negative sign out the front of it to. Instantaneous rate the rate at a specific time. Initial rate the rate at the very beginning of the reaction (t=0) signify that this is the rate of the reactants being consumed. If the rate is positive, this is the rate of the products being produced. Reaction rate is dependent on stoichiometric coefficients of the reactants and the products. Remember the rate of the consumption of the products equals the rate of the formation of the reactants.

Related Questions

What is the instantaneous rate of the reaction at t=800s?

The answer is rate= 6.8x10^-5 m/s but I need an explanation as to how to do the problem

An average reaction rate is calculated as the change in theconcentration of reactants or products over a period of time in thecourse of the reaction. An instantaneous reaction rate is the rateat a particular moment in the reaction and is usually determinedgraphically.

The reaction of compound A forming compound B was studied and thefollowing data were collected:

Time (s) [A](M)
0. 0.184
200. 0.129
500. 0.069
800. 0.031
1200. 0.019
1500. 0.016

a.) What is the average reaction rate between 0. and 1500. s?
b.) What is the average reaction rate between 200. s and 1200.s?
c.) What is the instantaneous rate of the reaction at t=800s?

Please show units of measure

byzantiumyellowjacket49

A student studies the kinetics of reaction 1 below using a clock reaction technique, reaction 2, and the procedures given in this experiment. For reaction mixture 1, he measures a time to color change of 121 seconds and for reaction mixture 2, he measures a time of 58 seconds. The temperatures of the reaction mixtures were the same for both experiments.

6Iâ (aq)+ BrO3â (aq) + 6H+(aq) --> 3I2 (aq) + Brâ (aq) + 3H2O(l) (Reaction1,slow)

I2 (aq) + 2 S2O32â (aq) --> 2 Iâ (aq) + S4O62â (aq) (Reaction 2, fast)

a. Determine the change in concentration of S2O32â that occurred during the time period measured. This should be the same for both the reaction mixtures. First, use M1V1=M2V2 to determine the initial concentration of the S2O32â after mixing the contents of the two flasks but before the reaction begins. Next, find the final concentration of S2O32â by remembering that all the S2O32â is consumed when the color change occurs. You can then find the change in the concentration of S2O32â.

[S2O32â]0 =

â[S2O32â] =

b. Use the stoichiometry of Reactions 1 and 2 to determine the change in concentration of BrO3â during

the same time period. â[BrO3â] =

c. Calculate the initial rate for each reaction mixture. Recall that Rate = â â[BrOâ ] / ât

Rate for mixture 1:

Rate for mixture 2:

d. Method of Initial Rates

Complete the table below using M1V1=M2V2 to find the initial concentration of each reactant after mixing the contents of flasks I and II for both reaction mixtures. Enter the initial rates computed above.

Rxn Mixture [Iâ]0(M) [BrO3â]0(M) [H+]0 (M) Rate (M/s)

Use the method of initial rates and the relevant data above to determine the order of reaction 1 with respect to the concentration of iodide ions.

Order with respect to [Iâ]:_________________________

e. It is critical for the success of this experiment that the concentrations of the reactants Iâ, BrO3â, and H+ do not change significantly over the time period measured.

Why is this important?

f. By what percent did the bromate ion concentration change during the time period considered for mixture 1 in this experiment?

PercentChange = (|â[BrO3â ]| / [BrO3â ]0 ) x 100%

CHEM10007 Lecture Notes - Lecture 21: Acid Strength, Signify, Geis

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