C1 2012 Flashcards
Write an equation for a reaction between NO and CO that occurs in a catalytic converter when these gases are removed
2NO + 2CO -> 2CO2 + N2
Identify one substance that could be used to remove this gas
Suggest one reason other than cost why this substance is used
CaO
Neutralises the gas
SO2 is acidic
Suggest one reason why the yield of nitrogen dioxide formed during this reaction is often less than expected
Decomposition not complete
Suggest one reason why it is difficult to obtain a pure sample of nitrogen dioxide from this reaction
Hard to separate
Explain why a catalyst has no effect on the position of an equilibrium
Catalyst increase rate of forward and backward reaction
Rate is the same
State why industry uses a pressure lower than 35mPa
Expensive equipment required
State why industry uses a temperature higher than 600K
Higher rate of reaction
Suggest why it is not possible to measure the enthalpy change directly for the following combustion reaction
(CO not only product)
State Hess’ Law
Enthalpy change at constant pressure is independent of the route
State meaning of standard enthalpy of combustion
The enthalpy change at constant pressure when 1 mole of a compound completely reacts with oxygen with all reactants and products under standard conditions
State why the value quoted in part c for the standard enthalpy of formation of CO2 is the same as the value for the standard enthalpy of combustion of carbon
Same no and same type of bonds broken
In terms of the forces acting on particles suggest one reason why the first electron affinity of oxygen is an exothermic process
Attractive force between the nucleus of O atom and on external e-
The freezing of water is an exothermic process. give one reason why the temp of a sample of water can stay at constant value of 0oC when it freezes
Heat given out escapes
By considering the properties of the reactants and products, state why it is possible to use a spectrometer to measure the conc of the manganate ions in this reaction mixture
Manganate ions are coloured.
All other reactants are not coloured
By considering the properties of the reactants and products, state why it is possible to use a spectrometer to measure the conc of the manganate ions in this reaction mixture
Manganate ions are coloured.
All other reactants are not coloured
