Unit 1

Kinetics

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

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