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98 Cards in this Set
- Front
- Back
During electrolysis of Aqueous NaCl, what is produced at each electrode? |
Reduction at cathode producing oxygen: 2H2O > 4H+ + O2 + 4e-
Oxidation at anode producing halide: 2Cl- > 2Cl + 2e- |
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What does the cathode attract? |
Positive cations as it's negative |
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What does the anode attract? |
Anions as they are positive |
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What is the half equation for hydrogen formed at the cathode? And when does hydrogen form at the cathode? |
2H+ + 2e- > H2
Formed when acids are in solution |
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What is the half equation for hydrogen formed at the cathode? And when does hydrogen form at the cathode? |
2H+ + 2e- > H2
Formed when acids are in solution |
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When is oxygen formed at the cathode during electrolysis of an aqueous ionic compound? What is the equation? |
Oxygen formed when a group 1, 2 or aluminium metal is in the ionic compound.
2H2O > 4H+ + O2 + 4e- |
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When are hydroxides produced at the anode during the electrolysis of aqueous ionic compounds? What is the equation? |
Produced if the salt is a sulfate or nitrate
2H2O + 2e- > H2 + 2OH- |
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When is oxygen produced at the anode during the electrolysis of aqueous ionic compounds? Give the half equation |
When there are hydroxides present in the compound. 4OH- > O2 + 2H2O + 2e- |
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In an aqueous ionic compound (CaCl2) undergoing electrolysis; what is produced at the anode and what is produced at the cathode? |
Chloride a halide so a halogen produced at the anode: 2Cl- > Cl2 + 2e- At the cathode oxygen will be produced as calcium is a group 2 metal. So, 2H2O > 4e- + O2 + 4H+ |
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How do you calculate atom economy? |
Total relative formula mass of useful products / total relative formula mass of all products x 100 |
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How do you calculate atom economy? |
Total relative formula mass of useful products / total relative formula mass of all products x 100 |
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Why is 100% atom economy desirable? |
It produces only intended products. An excess of waste products increase pollution and cost to dispose of. |
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How do you calculate atom economy? |
Total relative formula mass of useful products / total relative formula mass of all products x 100 |
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Why is 100% atom economy desirable? |
It produces only intended products. An excess of waste products increase pollution and cost to dispose of. |
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If the oxidation state of an element has increased (become more positive), what has happened? |
It has been oxidised |
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What is the trend in volatility of group 7 (halogens)? |
It decreases as you go down the group. So fluorine most volatile so has lowest boiling point |
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What is the trend in volatility of group 7 (halogens)? |
It decreases as you go down the group. So fluorine most volatile so has lowest boiling point |
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Definition of volatility |
An elements susceptibility to change quickly from liquid or solid to a gas |
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What does chlorine look like at RTP? |
Pale green gas |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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Appearance of iodine at RTP |
Grey solid which turns to purple has of heated |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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Appearance of iodine at RTP |
Grey solid which turns to purple has of heated |
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Compare the solubility of halogens in organic solvents and water |
Very soluble in non polar solvents. Much less soluble in water. |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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Appearance of iodine at RTP |
Grey solid which turns to purple has of heated |
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Compare the solubility of halogens in organic solvents and water |
Very soluble in non polar solvents. Much less soluble in water. |
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Appearance of chlorine, bromine and iodine in when aqueous |
Chlorine: pale yellow Bromine: orange Iodine: brown |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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Appearance of iodine at RTP |
Grey solid which turns to purple has of heated |
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Compare the solubility of halogens in organic solvents and water |
Very soluble in non polar solvents. Much less soluble in water. |
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Appearance of chlorine, bromine and iodine in when aqueous |
Chlorine: pale yellow Bromine: orange Iodine: brown |
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When aqueous chloride ions are added to silver nitrate what colour precipitate of formed? |
White - it will dissolve in dilute ammonia |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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Appearance of iodine at RTP |
Grey solid which turns to purple has of heated |
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Compare the solubility of halogens in organic solvents and water |
Very soluble in non polar solvents. Much less soluble in water. |
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Appearance of chlorine, bromine and iodine in when aqueous |
Chlorine: pale yellow Bromine: orange Iodine: brown |
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When aqueous chloride ions are added to silver nitrate what colour precipitate of formed? |
White - it will dissolve in dilute ammonia |
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What colour precipitate will form when silver bromide comes out of solution? |
Cream - this will dissolve in excess conc. ammonia |
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What does chlorine look like at RTP? |
Pale green gas |
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Appearance of bromine at RTP |
Red-brown liquid |
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What colour vapour would bromine give off? |
Orange vapour |
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Appearance of iodine at RTP |
Grey solid which turns to purple has of heated |
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Compare the solubility of halogens in organic solvents and water |
Very soluble in non polar solvents. Much less soluble in water. |
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Appearance of chlorine, bromine and iodine in when aqueous |
Chlorine: pale yellow Bromine: orange Iodine: brown |
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When aqueous chloride ions are added to silver nitrate what colour precipitate of formed? |
White - it will dissolve in dilute ammonia |
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What colour precipitate will form when silver bromide comes out of solution? |
Cream - this will dissolve in excess conc. ammonia |
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What colour will silver bromide compounds go when filtered out of solution? |
Yellow - won't dissolve in ammonia |
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How can you tell Cl-, Br- and I- ions apart? |
Add silver nitrate. They all give different colour precipitates: Cl- (white), Br- (cream) and I- (yellow). If doesn't dissolve in ammonia then iodide. If dissolves in diluted ammonia then chloride. If dissolves in excess of conc. ammonia then bromide. |
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If hydrogen halides are exposed to moist air what is observed? |
Steamy fumes |
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If hydrogen halides are exposed to moist air what is observed? |
Steamy fumes |
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If ammonia and hydrogen halides react what is observed? |
Copious amounts of white steamy fumes |
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If hydrogen halides are exposed to moist air what is observed? |
Steamy fumes |
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If ammonia and hydrogen halides react what is observed? |
Copious amounts of white steamy fumes |
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H-F + NH3 > NH4F What acts as the base and what acts as the acid here? |
Ammonia- base Hydrogen ion - acid |
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Definition of dynamic equilibrium |
The state where the forward reaction is happening at the same rate of as the reverse reaction. The results showing that the conc. of the reactants and products are constant within a closed system |
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Definition of dynamic equilibrium |
The state where the forward reaction is happening at the same rate of as the reverse reaction. The results showing that the conc. of the reactants and products are constant within a closed system |
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Definition of closed system |
A situation where no substances can enter or leave the system. e.g. Sealed tank |
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Where would the position of equilibrium lie if there concentration of products was higher than that of reactants? |
To the right |
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What factors out of these can affect: pressure, concentration, catalysts and temperature |
Only temperature |
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What factors out of these can affect: pressure, concentration, catalysts and temperature |
Only temperature |
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What is the effect on Kc when the pressure of the closed system is increased? |
The position moves to the side of the reaction with less miles of gas |
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What factors out of these can affect: pressure, concentration, catalysts and temperature |
Only temperature |
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What is the effect on Kc when the pressure of the closed system is increased? |
The position moves to the side of the reaction with less miles of gas |
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What happens to the position of equilibrium when the pressure is decreased? |
It will move to the side of the reaction with more moles of gas |
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What factors out of these can affect: pressure, concentration, catalysts and temperature |
Only temperature |
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What is the effect on Kc when the pressure of the closed system is increased? |
The position moves to the side of the reaction with less miles of gas |
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What happens to the position of equilibrium when the pressure is decreased? |
It will move to the side of the reaction with more moles of gas |
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What happens to the position of equilibrium when the temperature is increased? |
Will move in the direction which involves an endothermic change. To decrease temperature as much a possible. |
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What happens to the position of equilibrium when the temperature is decreased? |
Position will move to which ever direction has an exothermic change. Increasing energy. |
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What happens to the position of equilibrium when the temperature is decreased? |
Position will move to which ever direction has an exothermic change. Increasing energy. |
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What is the effect of a catalyst on equilibrium? |
No effects. It simply speeds up reaction. |
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What is the effect of increasing the rate of reaction by increasing concentration? |
More particles per unit volume. So a higher frequency of collisions per second. So higher rate of reaction. |
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What is the effect of increasing the rate of reaction by increasing concentration? |
More particles per unit volume. So a higher frequency of collisions per second. So higher rate of reaction. |
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Effect on increasing pressure on rate of reaction |
More particles per unit volume. Higher frequency of collisions with combined kinetic energy exceeding the activation enthalpy per second. Increased rate of reaction. |
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Effect of increased surface area in rate of reaction |
Greater proportion of particles exposed for collision with combined kinetic energy exceeding the activation enthalpy. More collision per second. Increased rate of reaction. |
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Effect of temperature on rate of reaction |
Average kinetic energy of the reactant particles increased. So combined kinetic energy of collisions will involve a combined kinetic energy that's equal too or greater than the activation enthalpy. Increased rate of reaction. Also more collisions per second as higher kinetic energy induced higher velocity. |
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Effect of temperature on rate of reaction |
Average kinetic energy of the reactant particles increased. So combined kinetic energy of collisions will involve a combined kinetic energy that's equal too or greater than the activation enthalpy. Increased rate of reaction. Also more collisions per second as higher kinetic energy induced higher velocity. |
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Effect of a catalyst on rate of reaction |
Provides and alternative pathway with a lower activation enthalpy. A higher proportion of collisions will involve a combined kinetic energy that is equal to or greater than the activation enthalpy so a higher rate of reaction |
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Write the rate equation |
Rate = change in concentration / time taken |
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What is rate measured in? |
mol dm-3 s-1 |
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What is rate measured in? |
mol dm-3 s-1 |
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How can colorimetry be used to measure the rate of reaction by measuring concentration change? Give the procedure |
Using a sustainable filter find the complimentary colour to the coloured substance in the equation. Zero the colour colorimeter using distilled water then calibrate it. Make up some solutions of the substance with known concentrations. measure the absorbance of the coloured substance at certain time intervals. Then plot a calibration graph, which is absorbance over concentration. After this plot a progress graph of time over concentration then draw a tangent at X equals zero and measure the gradient. |