C6: Chemical Synthesis Flashcards
Name two chemicals you might come across in everday life
Cleaning products, paints, dyes, fertillisers, food additives, drugs.
Give an example of a chemical made on a small scale
Pharmaceticals are produced on a smaller scale.
Give an example of chemicals made on a large scale
Sulfuric acid
State whether the following are acid, alkali or neutral. pH 2 pH 13 pH 0 pH 7
ACID
ALKALI
ACID
NEUTRAL
Give an example of a pure acidic compound that is a liquid
Nitric acid, sulfuric acid, ethanoic acid
Give two ways of measuring the pH of a substance
Litmus paper, Universal indicator with a pH scale & pH meters
What types of ions are always present in a) acid b) alkalis dissolved in water
a) H+
b) OH-
Write the equation for the ions in acids and alkalis
H+ + OH- —-> H2O
When designing a chemical process what is involved in carrying out a risk assesment?
Identifying hazards, assesing who could be harmed & deciding what action should be taken to reduce risk
What does calculating the yield tell you about a reaction?
Tells you the overall sucess of the process
How would you seperate an insouble product from a liquid reaction mixture?
Filtration
Name two stages in synthesis of a chemical where evaporation can be useful
Isolating the product and purification
Give two methods used to dry a product
Dried in a drying oven or a desiccator
What is the formula for percentage yield?
Actual yield divided by theoretical yield x 100
Why is purifciation of a product important?
Important in production of pharmaceuticals, impurities could do more harm than good. Also in petrochemicals impurites could cause damage to the cars engine.
DEFINE: Endothermic
A reaction which takes in energy from the surroundings, usually in the form of heat and shown by a fall in temperature
DEFINE: Exothermic
A reaction which gives out energy to the surrondings, usually shown by a rise in temperature
Give two reasons why it is important to control the rate of reaction in industry
If the reaction mixture gets too hot, the reactants or product could become gasees, which could increase pressure and cause an explosion.
If the reaction is endothermic heats needs to be supplied otherwise it will be to cold for the reaction to take place& equipment could be damaged by freezing
What four things affect rate of reaction?
Temperature
Concentration
Surface Area
Use of enzyme/Catalyst
Give three ways you could mesure rate of reaction
1) Precipitation and colour change
2) Change in Mass
3) Volume of gas given off
Give an advantage and disavantage of the Preciptation and Colour change method
Works for reactions where the inital solution is see-through
Results are very subjective, different people might not agree on the exact point where the mark disappears of the solution changes colour
Give an advantage and disadvantage of the Change in Mass method
Rate of reatciongraphs are easy to plot using results from this data and is the most accurate.
Disadvantage is it releases the gas straight into the room
Give an advantage and disadvantage of the Volume of gas method
Gas syringes will give a fairly accurate result to nearest cm3.
Disadvantage if the reaction is too vigorous the plunger could easily blow of the end.
