Chem p2 Flashcards
How does the equilibrium change when there is more reactants than products?
The equilibrium shifts to favour the left
How does the equilibrium change when there are more products than reactants?
Equilibrium shifts to favour the right
What side does equilbrium favour when a reaction is cooled?
When a reaction is cooled, equilibrium favours the left / the endothermic reaction in a reversible reaction to take in heat energy
What side does equilibrium favour when a reaction is heated?
When a reaction is heated, equilibrium favours the right / the exothermic reaction in a reversible reaction to release energy
What side does equilbrium favour when pressure of a reaction increases?
When the pressure of a reaction increases, the equilibrium favours the side with the fewer molecules of gas
What side does equilibrium favour when pressure of a reaction decreases?
When the pressure of a reaction decreases, the equlibrium favours the side with more molecules of gas
How does a system respond when the amount of reactants increase?
When the amount of reactants increase, the system makes more products
How does a system respond when the amount of reactants decrease?
When reactants decrease, the system will make more reactants
What is the test for alkenes?
The test for alkenes is the bromine test = orange solution becomes colourless if alkenes are present
What are the properties of alcohol?
The properties of alcohol include: flammable, soluble in water (they give neutral solutions), reacts with sodium to form hydrogen gas, oxidised by oxidising agents to form carboxylic acids
What are the key uses of alcohol?
Key uses of alcohol include fuels and solvents
What is fermentation?
Fermentation is when an enzyme in yeast is used to convert sugar solutions to aqueous solutions of ethanol
What is the reaction to fermentation?
Sugar > Ethanol + CO2
What are the properties of carboxylic acids?
Properties of carboxylic acids: weak acids, higher pH than strong acids
What are esters?
Esters are molecules formed when an alcohol reacts with a carboxylic acid
What is the reaction for producing esters?
Alcohol + carboxylic acid > ester + water
What is a pure substance in chemistry?
Pure substance is a substance containing only one element or compound
What will a pure substance do?
A pure substance will melt at a specific temperature and boil at a specific temperature
What will an impure substance do?
An impurity will lower melting point + increase melting range, increase boiling point + may increase boiling range
What is a formulation?
A formulation is a useful mixture with a precise purpose eg alloys, medicines, food, fuels
What is the test for hydrogen gas?
Hydrogen burns quickly with a pop
What is the test for oxygen gas?
Oxygen relights a glowing splint
What is the test for chlorine?
Damp litmus paper will turn white if chlorine is present
What is the test for carbon dioxide?
Carbon dioxide turns limewater cloudy
What are anions?
Anions are ions with a negative charge
What are cations?
Cations are ions with a positive charge
How do we test for sulfates?
Test for sulfates by adding dilute hydrochloric acid to barium chloride solution. If sulfates are present, a white precipitate will form
How do we test for carbonates?
Test for carbonates by adding dilute acid and connecting it to a tube of limewater. Carbonate ions will react to form co2 > cloudiness
How do we test for halides?
Halids include adding dilute nitric acid to silver nitrate solution.
Chloride - white precipitate
Bromide - cream precipitate
Iodide - yellow precipitate
What are the results of the cations in the flame test?
Lithium = red Sodium = yellow Potassium = lilac Calcium = orange Copper = green
What is the disadvantage of flame tests?
In flame tests, if the sample contains a mix of metal ions, flame colours may be hidden by other flame
What are the advantages of instrumental analysis?
Sensitive (Detects tiny amounts), fast, accurate are advantages of instrumental analysis
What can the light spectra in flame emission spectroscopy do?
The lights can help identify ions in solution and determine the concentration of the ions - intensity of the line
What happens in flame emission spectroscopy?
In FES, the sample is heated in flame > light analysed in spectrum > line spectrum of different wavelengths of light is produced
How has the atmosphere developed over time?
Intense volcanic activity > nitrogen and carbon dioxide mostly in the atmosphere> water vapour condensed to form oceans, layers of sediment formed from carbonate precipitates
What is crude oil and natural gas formed from?
Crude oil and natural gas is formed from compressed plankton deposits
What is coal formed from?
Coal is formed from compressed plant deposits
What is limestone formed from?
Limestone is formed from compressed calcium carbonate deposits from shells and marine skeletons
What is the composition of the current atmosphere?
80% = nitrogen, 19% = oxygen, 1% = other gases eg h20 vapour, co2, ch4
What is carbon monoxide formed from and what can it cause?
Carbon monoxide is formed from incomplete combustion and can cause comas and death
What is carbon particulates formed from and what can it cause?
Carbon particulates are formed from incomplete combustion and can cause global dimming
What is sulfur dioxide formed from and what can it cause?
Sulfur dioxide is caused by oxidation of sulfur impurities and can cause acidic rain
What is oxides of nitrogen formed from and what can it cause?
Oxides of nitrogen are caused by heat of fossil fuels can causes acid rain
What is the process of phytomining?
Phytomining is when plants are planted in soil containing copper > copper builds up in leaves > plants are burnt > ash contains copper ions
What is the process of bioleaching?
Bioleaching involves bacteria mixing with low grade ore > makes copper compounds soluble > leachate solution is electrolysed
What are the two processes involved in desalination?
Distillation (boiling water to separate out from dissolved salts), Reverse Osmosis (passing water through membranes that only water molecules are allowed to pass through)
How is sewage water treated?
Sewage water:
1) screening
2) sedimentation
effluent > aerobic digestion of organic matter > back into the environment
sludge > anaerobic digestion of organic matter > natural gas or fertiliser
