Advanced Information Flashcards
How changes in concentration affect the rates of reaction
1) Use measuring cylinder, add 50 cm3 of dilute sodium thiosulfate solution to a conical flask
2) Place the conical flask on a printed black cross
3) Add 10 cm3 of dilute hydrochloric acid to the conical flask
4) Swirl flask and start a stopwatch
4) Look down through the reaction mixture
5) When cross is no longer seen stop stopwatch
6) Repeat experiment with lower concentrations of sodium thiosulfate
7) Repeat whole experiment 3 times and calculate mean leaving out anomalies
Test for hydrogen
Lighted splint “pops”
Test for oxygen
Glowing splint relights
Test for carbon dioxide
Limewater turns milky
Test for chlorine
Damp blue litmus paper turns white
How to remember flame test colours?
Let’s / Corn Lithium. / Crimson
Call / OR Calcium. / Orange-red
Pigs / Lemons Potassium. / Lilac
Crazy / Give Copper. / Green
So / Yellow Sodium. / Yellow
Calculate the rate of reaction
Draw tangent
Up / Bottom = gradient
Methods to measure rate of reactions?
1) decreasing volume of gas given off = conical flask on balance with cotton wool at top, gas escapes through cotton wool, see mass decrease on scale
2) increasing volume of gas given = conical flask with mixture releasing gas, gas syringe fills gives you mass change
3) solution turns cloudy = x spot paper under flask, x spot disappears…
Equation to calculate mean rate of reaction
Quantity of reactant used / time
Quantity of product formed / tine
Rule with exothermic and endothermic in reversible reactions
Forward is exothermic, so reverse is endothermic
Forward is endothermic, so reverse is exothermic
La Chatelier’s Principle
Whatever you do to the forward reaction, the reverse reaction will do the opposite
Pressure in equilibrium
Equilibrium shifts to reduce pressure
Increase pressure = shifts to the side with fewer moles (shift to right in eg)
Decrease pressure = shifts to side with more moles (shift to left in eg)
E.g. 2NO <=> NO (only looking at big numbers)
Crude oil
Finite resource
Found in rocks
Liquid
Mixture of different hydrocarbons separated using fractional distillation by their different boiling points
Alkane general formula
CnH2n+2
Number of carbon atoms in prefixes
CH4 = meth C2H6 = eth C3H8 = prop C4H10 = but