C5: Seperate Chemistry 1 Flashcards

Question

What is the atom economy of a reaction?

Answer 1

Atom economy is a measure of the efficiency of the reaction. It looks at the amount of reactants that get turned into useful products.

Answer 2

- Higher atom economy. - Higher yield. - Faster rate. - Equilibrium position favours products more. - By-products are more useful / less harmful.

Answer 3

At the same temperature and pressure, equal amounts of gas will occupy the same volume.

Answer 4

The volume occupied by one mole of molecules of any gas at room temperature and pressure.

Answer 5

Room temperature and pressure: - 20°C - 1 atmosphere

Answer 6

A higher temperature means equilibrium is reached quicker. This is because the reacting particles have more kinetic energy so there are more frequent successful collisions.

Answer 7

Equilibrium is reached faster when a catalyst is used because the catalyst provides an alternative reaction pathway with a lower activation energy.

Answer 8

Equilibrium is reached faster with a higher pressure. This is because there are more particles in the same volume (or the same number of particles in a smaller volume) so more collisions between reacting particles.

Answer 9

Equilibrium is reached faster at a higher concentration. This is because there are more particles in the same volume so more collisions between the reacting particles.

Answer 10

- Availability and cost of raw materials. - Energy requirements. - Optimum temperature and pressure for high yield and fast rate of reaction. - Need for a catalyst.

Answer 11

To promote plant growth.

Answer 12

Nitrogen, phosphorus and potassium compounds.

Answer 13

A combination of all three fertiliser compounds: nitrogen, phosphorus and potassium compounds.

Answer 14

Nitrogen: Healthy leaves. Phosphorus: Healthy roots. Potassium: Growth and healthy fruit / flowers.

Answer 15

Ammonium nitrate

Answer 16

Titration between ammonia and sulfuric acid: - Exact volume of NH added to a conical flask using a pipette. - Add a few drops of indicator. - Add H,SO, from the burette drop by drop. Stop when the indicator changes colour. - Repeat, adding the exact volumes of reactants without the indicator (as it is an impurity). - Remove the water by evaporation and crystallisation, leaving pure crystals.

Answer 17

Raw materials obtained from the Haber process (ammonia) and the contact process (sulfuric acid). A large reactor chamber is filled with ammonia gas. Sulfuric acid is sprayed into the chamber from above. Ammonium sulfate crystals are produced.

Answer 18

Laboratory method Faster rate of reaction. Small reactant quantities can easily be bought. Room temperature and pressure Simple equipment required. Very small yield. Industrial process Very expensive and complex. Continuous process so continuous yield. Large volumes of product. Slow rate of reaction. High energy requirement. Other industrial processes required to obtain the reactants.

Answer 19

Two metals of different reactivities are placed in an electrolyte. The more reactive metal releases electrons, becoming positively charged. The electrons flow to the other electrode which becomes negatively charged. The difference in the ability of each electrode to release electrons causes a voltage to be produced.

Answer 20

When one of the reactants has been used up.

Answer 21

A cell that continually produces a voltage as long as it is supplied with oxygen and a fuel (like hydrogen).

Answer 22

Hydrogen and oxygen are pumped through porous electrodes. The electrolyte is often an acid such as phosphoric acid. Hydrogen and oxygen react, producing electricity and water.

Answer 23

- No pollution produced. - Produce more energy than an alternative fuel like petrol. - Continuous process as long as fuel is supplied.

Answer 24

- Materials used to make them are expensive. - High pressure tanks required to store oxygen and fuels like hydrogen. - Hydrogen is expensive and hard to store. - Efficiency is affected by temperature.