Topic 1

Rate of Reaction

Introduction

Mconcentration

mass g

mLLvolume

(s)

(g)

(aq)

UnitAmountState of Reactant

Δ means change

Δ in Time

Δ in Amount of Reactant or ProductReaction Rate =

Time Units

s

min

h

moles/s

M/min

mL/h

g/min

Rate Units

Measuring Reaction Rates

Reactants → Products

Decrease Increase as you measure them

CaCO3(s) + 2HCl(aq) → CO2(g) + CaCl2(aq) + H2O(l)

The water concentration does not change- like a drop in a bucket, as the solution is mostly water.

increaseM / minConcentration / time

increasemL / hVolume / time

Concentration / time M / s decrease

g / min decreaseMass / time

Property Measured Units Change

Two types of calculations

2. Measure rate of reaction of a substance from given information of other substance

Mg + 2HCl MgCl2 + H2

Given= 12 g Mg used in 30 secondFind Rate of formation (mole/s) of H2?

Two types of calculations

1.Measure rate of reaction of a single substance from given information of the substance Mg + 2HCl MgCl2 + H2

Given= 12 g Mg used in 30 secondFind Rate of Mg consumption per second

Discussion Time

A should tell B and B should rephrase I know how to 1. A .????? B. Do you mean --------- 2. A .????? B. Do you mean ---------3. A .????? B. Do you mean ---------4. A .????? B. Do you mean ---------5. A .????? B. Do you mean ---------

A Tell B and B rephrase 1. Rate of reaction formula2. units3. Increase and decrease of reactant and product amount4. Convert time units5. Convert mass to mole, volume to mole 6. How to draw graph, dependent and independent variables

Measurable Changes

Mass Volume

Size Pressure

Shape Colour

Time Temperature

1. Volume

Volume (mL) 4.0 5.1 5.9 6.8 7.6 8.3

Time (s) 0 15 30 45 60 75

Zn(s) + 2HCl(aq) → H2(g) + ZnCl2(aq)

 

 

 

Rate in mL H2 /s = 8.3 - 4.0 mL = 0.057 ml/s75 - 0 s

Rate in mole H2/min @ STP

0.057 mL s

x 1 L 1000 mL

x 1 mole 22.4 L

x 60 s1 min

= 1.5 x 10-4 mole/min

1.5 x 10-4 mole H2

minx 2 moles HCl

1 mole H2

x 36.5 g x 60 min = 0.67 g/h1 mole 1 h

Rate in g HCl/h

2. Mass of an open container 

Mass (g) 82.07 81.84 81.71 81.66 81.64 81.63

Time (s) 0 15 30 45 60 75

CaCO3(s) + 2HCl(aq) → CO2(g) + CaCl2(aq) + H2O(l)

CaCO3(s) + 2HCl(aq) → CO2(g) + CaCl2(aq) + H2O(l)

1. Calculate the rate in units of grams CO2/s.

Rate = (82.07 - 81.63) g = 0.0059 g/s75 s

x 1 mole x 1 mole CaCO3 x 100.1 g x 3600 s = 48 g/h0.0059 g CO2

s 44.0 g 1 mole CO2 1 mole 1 h

2. Calculate the rate in grams CaCO3/h

Keep all sig figs on calculator

Round final answer

3. Pressure in a closed container Ca(s) + 2HOH(l) → Ca(OH)2(aq) + H2(g)

 Diagram

4. Colour of Solution Cu(s) + 2AgNO3(aq) → 2Ag(s) + Cu(NO3)2(aq)

  clear blue

5. If 0.895 g of H2SO4 is neutralized with 0.50 M NaOH in

30.0 s, what is the reaction rate in moles NaOH /min.

H2SO4 + 2NaOH →

All 0.895 g is used up and some of the 0.50 M is consumed.

Rate =0.895 g H2SO4 x 1 mole x 2 moles NaOH

98.1 g 1 mole H2SO4

0.500 min

= 0.0365 moles NaOH/min

Workbook Questions

Page 2 Question 1-5

Part of hypothesis

A Tell B and B rephrase 1. Rate of reaction formula, rearrange formula 2. Units and prefix conversion3. Increase and decrease of reactant and product amount4. Convert time units5. Convert mass to mole, volume to mole 6. How to draw graph, dependent and independent variables7. Rate of reaction of single substance8. Rate of reaction of a substance from other substance9. Average and Instanteous reaction rate calculations