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Analysis and rates (including rp5 and 7) - Coggle Diagram
Analysis and rates (including rp5 and 7)
Flame test method (rp7)
Dip wire in hydrochloric acid, then put into flame
Repeat until wire is clean (no flame colour)
Must be done otherwise colour from an impurity could mask flame colour of sample
Dip wire in hydrochloric acid then into sample
Put wire with sample on in the flame and observe the colour of the flame
Testing for metal ions
Lithium - Li+
Crimson flame colour
Sodium - Na+
Yellow flame colour
Potassium - K+
Lilac flame colour
Calcium - Ca2+
Red flame colour
Copper (II) - Cu2+
Green flame colour
Magnesium, Aluminium, Iron (II) and (III) are all colourless flame colours
Testing for cations (NaOH test)
Mg2+, Al3+ and Ca2+ all have a white precipitate when NaOH is added
Mg2+ has no flame colour
Al3+ dissolves with excess NaOH
Ca2+ burns with a brick red colour
Disappearing cross
Measure 50cm3 of sodium thiosulfate using a measuring cylinder and transfer into a conical flask
Measure 5cm3 of hydrochloric acid using a measuring cylinder
Heat the conical flask full of sodium thiosulfate using a tripod and gauze until it reaches the desired temperature
Place the flask on the cross and pour in the dilute hydrochloric acid
Start the stopwatch and measure temperature of the mixture whilst gently swirling th flask
Stop the timer when the cross is no longer visible (look down through the flask)
Measure the final temperature and calculate mean temperature during the reaction
Collision Theory
For reactions to occur:
Collisions of particles
Energy > Activation Energy
Concentration
More crowded particles
More frequent collisions
Greater rate of reaction
Surface Area
Higher SA means more exposed Particles
More frequent collisions
Higher probability of successful collisions
Increasing temperature
Faster particles - More frequent collisions
more energy = more energetic collisions
A lot more successful collisions
Catalyst
Speeds up reactions
Not used up
lowers activation energy - more successful collisions