Chapter 7 Flashcards

Question

Supplying electricity

Answer 1

- electricity is transmitted along power cables made from copper because of its properties: good conductor - over head power cables are made from aluminum because of ; good conductor, low density, resistance to corrosion - domestic cables are covered in plastic for safety - leakage of power from overhead cables is prevented by using ceramic materials between the cables and the plums

Answer 2

Instead of dipping some materials to be tested into liquid circuit, graphite rods are dipped into the test liquid l. Liquids compounds, solutions are molten material can be tested in this way - •electrolytes : liquids that conduct electricity by movement of ions are called electrolyes - •liquids that do not conduct electricity in this way are called non-electrolytes

Answer 3

The conductivity of ionic compounds is explained by the fact that ions move in a particular direction an electric field -electrodes are rods (graphite) that carry current into and out of the solution

Answer 4

The apparatus in which electrolysis is carried out is known as an electrolytic cell - the direct current (DC) is supplied by a battery or power pack - graphite electrodes Garry that current into and out of the liquid electrolyte. Graphite is chosen because it is quite un-reactive - electrons flow from negative terminal to positive terminal around the circuit - in the electrolyte is the ions that move to carry the current

Answer 5

The more reactive a metal, the more it tends to stay as ions and not be discharged. The H*+ ions will accept electrons instead and hydrogen molecules will be formed, leaving the ion at the reactive ions eg: not ions in solution ( compare between CU*2+ (less reacted) and (H*+)

Answer 6

- Na*+ and H*+ flow to the cathode. But It is H*+ that affects electrons as sodium is made reactive than hydrogen - then the 2 hydrogen the atoms combine liquid to form a hydrogen molecule - so the overall, hydrogen gas bubble off at the cathode - Cl- and OH- travel to the anode. CL- ions are discussed more readily than OH-

Answer 7

Pure water (bad conductor) + acid - an example of electrolytic cell use for electrolysis Of brine - it is the safest for the environment and uses the least electricity - other types of cell use either a flaming mercury cathode or a discharged (partition ) made from asbestos - titanium’s chosen for the anode as it is not affected by chlorine - a membrane separated the anode and cathode components. This membrane is selective because it only allows Ana ions and water to flow through but no other ions - this means product are kept separate and cannot react with each other - the Na*+ and OH- ions collect in the cathode compartment - the NAOH solution is removed and purified

Answer 8

- can being def to coast one metal with another - cathode is the object to be played and the anode is made from the metal being used to plate it - the electrolyte is a salt of the same metal-as the process proceeds, the anode dissolved away into the solution replacing the metal plated onto the object - and the concentration of solution remains the same - most commentary used metals use for electroplating are copper, chromium, silver and tin - electroplating give a protective coating to the metal underneath - also attractive appearance - nickel silver is an alloy of copper, zinc and nickel. It contains no silver at all. (EPNS) meaning electroplated nickel silver :33’ on cutlery and other objects

Answer 9

Under same conditions in a closed system, the products can interact to reverse the reaction Used in industry for the reaction between niytogen and hydrogen to produce ammonia N2 + 3H2 2NH3 is that

Answer 10

Was the first to show this reaction could be controlled to make useful amounts of ammonia.now known as the Haber Process

Answer 11

Thermal decomposition of salts such as hydrated copper 2 sulfate results in the dehydration of the salt CuSO4.5H2O —-> CuSO4 + 5H2O (Some reactions for example dehydration or hydrate salts can be reversed if the conditions are changed)

Answer 12

Making ammonia Forward reaction: n2 + 3H2 -> 2NH3 Reverse reaction: 2NH3 -> N2 + 3H2

Answer 13

Dynamic equilibrium- a state of balance between continuing processes. It also states: when a change is made to the conditions of a system when a change is made to the conditions or a system in dynamic equilibrium, the system moves so as to oppose that change

Answer 14

- the rates of the forwards and reverse reactions are equal - the concentrations of reactants and products do not change - concentrations for a particular reaction depend on the conditions used. Changing temp alters the equilibrium position. Changing the working pressure can also alter the equilibrium position for some reactions involving gasses - a catalyst does not alter the equilibrium concentrations of reactants and products, it does increase the rate at which equilibrium is reached

Answer 15

* N2 and H2 are mixed in a ratio of 3:1 * an optimum temp of 450 is chosen * A pressure of 200 atm * catalyst final divided iron is used * the ammonia is condensed out of the reaction mixture and the remaining N2 and H2 is recycled

Answer 16

* catalyst -does not affect the position of equilibrium but at rate * temp - increasing makes reaction move in the direction that takes in heat (endothermic direction * concentration -increasing makes equilibrium move in the direction of that produces less of that substance * pressure -only affects reactions with gas, increasing shifts the equilibrium in the direction that produces fewer gas molecules

Answer 17

Manufacturing of sulfuric acid, converts sulfur dioxide(SO2) to sulfur trioxide (SO3) is reversible Exothermic and is favored by low * optimum temp of 450 * a catalysis or vanadium (v) oxide * operating pressure of about 1atm