Gr.11 T4 Chemistry Flashcards
What is an acid according to the Arrhenius model?
Won’t need to spell
Ionises in water to produce the hydrogen ion
What is a base according to the Arrhenius model?
Ionises in water to produce the hydroxide ion
What is an acid according to the Bronsted-Lowry model?
A proton donor
What is an a base according to the Bronsted-Lowry model?
A proton acceptor
Ampholytes
A substance that can act as an acid or base
Learn common acids and bases on p.242
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What are the 4 types of reactions of acids and bases?
Acid+metal ➡️ salt+hydrogen (electron transfer - redox rection)
Acid+metal hydroxide ➡️ salt+water (neutralisation)
Acid+metal oxide ➡️ salt+water
Acid+metal carbonate ➡️ salt+water+carbon dioxide
What are the properties of acids and bases?
Acids:
Taste sour.
Their aqueous solutions conduct electricity (called electrolytes)
React with certain metals to produce hydrogen gas
CO2 produced when acids react with limestone
Bases:
Taste bitter
Solutions of alkalis, bases that are soluble in water, conduct electricity (called electrolytes)
Generally feel slippery/ soapy
What is the colour of red litmus in an acid, base and neutral substance?
Acid: red
Base: blue
Neutral: red
What is the colour of blue litmus in an acid, base and neutral substance?
Acid: red
Base: blue
Neutral: blue
What is the colour of phenolphthalein in an acid, base and neutral substance?
Acid: colourless
Base: pink
Neutral: colourless
What is the colour of bromothymol blue in an acid, base and neutral substance?
Acid: yellow
Base: blue
Neutral: light green
What is the colour of methyl orange in an acid, base and neutral substance?
Acid: red
Base: orange
Neutral: orange
Indicators
Organic substances that change colour in acids and bases.
What is universal indicator?
A mixture of dyes that can change into many different colours. (Shows the full range of pH colours)
Titation
A process used to neutralise an acid or base and to determine the concentration of an unknown solution.
Oxidation
A loss in electrons
Reduction
A gain in electrons
Oxidation number/ oxidation state
A number assigned to each atom to keep track of electrons during a reaction
Give one exception to oxygen having an oxidation state of -2 (the only one I need to know)
H O
2 2
Oxygen has an oxidation state of -1
What is a reducing agent?
A substance that causes reduction but it itself is oxidised
What is an oxidising agent?
A substance that causes oxidation but it itself is reduced
What is a redox reaction?
The transfer of electrons
When does a hydrogen ion have an oxidation state of +1 and when does it have an oxidation state of -1?
+1 when bonded to non-metals
-1 when bonded to metals
What are the 3 classifications of redox reactions?
- Displacement reaction
- Synthesis reaction (2+ reactants, 1 product)
- Decomposition reaction (1 reactant, 2+ products)
What are the tests for oxygen gas and hydrogen gas?
Oxygen gas: glowing splint relights
Hydrogen gas: burning split ignites gas with popping sound
Electrochemical reaction
Oxidation and reduction take place in separate compartments
What energy transformation happens in an electrochemical reaction?
Chemical energy becomes electrical energy
Electrochemical cell
Energy from the redox reaction is used as a source of electric current
What happens at the anode and the cathode (oxidation/ reduction)? Does this cause the electrode to increase or decrease in mass?
Anode: oxidation (electrode decreases in mass)
Cathode: reduction (electrode increases in mass)
What are the two functions of the salt bridge in an electrochemical cell?
It completes the circuit and it ensures that the electrolytes remain neutral
Give the formula for the dichromate ion
-2
Cr O
2 7
In electrochemical cells, electrons flow through the wire and ions flow through the salt bridge and electrolytes
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What is an electrochemical cell called if it has:
1) a spontaneous chemical reaction between chemicals
2) a non-spontaneous chemical reaction driven by chemical energy
1) galvanic cell (or voltaic cell)
2) electrolytic cell
What is the name of the process that occurs in an electrolytic cell?
Electrolysis
Cell potential
The potential difference between the cathode and anode
What is a standard electrode potential?
The voltage measured under standard conditions when the half-cell is connected to a standard hydrogen electrode to form an electrochemical cell. (Measured in V)
What are standard conditions?
p = 1 atm
-3
c = 1 mol.dm
temp.= 25*C
Why is a platinum electrode used in a hydrogen half-cell?
It is chemically inert and a good electrical conductor.
Look at how to write equations using table 4A
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