C6

HideShow resource information
  • Created by: Faith16
  • Created on: 13-12-15 16:17
what is the chemical synthesis?
The process of making complex chemical compounds into simpler ones.
1 of 35
What types of chemicals do we use in day to day life?
Food additives(preservatives,colouring and flavouring), cleaning and decorating products (paints contain pigments and dyes, bleach,oven cleaner, washing-up liquid) , drugs, fertilisers (ammonia)
2 of 35
What are the pH levels for acids and alkalis?
Acids are pH0 to pH6 and alkalis are pH8 to pH14 (pH7 is neutral)
3 of 35
Give different types of acids.
Solids- citric acid is used as a food additive. Liquids- sulphuric acid, nitric acid. Gases- hydrogen chloride.
4 of 35
Give different types of alkalis.
Sodium hydroxide (used in bleach), potassium hydroxide (used in alkaline batteries) and calcium hydroxide (neutralise acidic soils).
5 of 35
How can you measure pH levels?
Litmus paper- red acidic, blue alkaline. Universal indicator- useful for estimating pH level. pH Metre- probe which is dipped into substance and gives the reading of the pH.
6 of 35
What do acids and alkalis always produce?
Acidic compounds produce aqueous hydrogen ions in water. Alkaline compounds produce aqueous hydroxide ions in water.
7 of 35
What is the neutralising symbol equation?
H+ (aq) + OH- (aq) = H2(small)O (l)
8 of 35
Acid+ Metal = ?
Salt + Hydrogen
9 of 35
Hydrochloric acid will always produce?
Chloride salts e.g. magnesium chloride, aluminium chloride, zinc chloride.
10 of 35
Sulphuric acid will always produce?
Sulfate salts e.g. magnesium sulfate, aluminium sulfate, zinc sulfate
11 of 35
Acid + Metal Oxide = ?
Salt + Water
12 of 35
Acid + Metal Hydroxide = ?
Salt + Water
13 of 35
Acid + Metal Carbonate = ?
Salt + Water + Carbon Dioxide
14 of 35
What are the seven stages involved in chemical synthesis? (see page 64 for more detail)
1. Choosing the reaction 2. Risk assessment 3.Calculating the quantities of reactants 4. Choosing the apparatus and conditions 5.Isolating the product 6. Purification 7. Measuring yield and purity
15 of 35
How is filtration used when isolating a product and purification?
Can be used if the product is insoluble solid that needs to be separated from liquid reaction mixture. It can be used for purification as well- solid impurities in the mixture can be separated using filtration.
16 of 35
How is evaporation and crystallisation used when isolating and product and purification?
Heating up the solution causes evaporation leaving behind solid crystals. The crystals have a regular structure that the impurities can't fit into.
17 of 35
How is drying used to isolate and purify?
The products can be dried in an drying oven or simply heat the sample by blowing hot, dry air over the product. Also dried using desiccators- contain chemicals like silicon gel that remove water.
18 of 35
What is actual, theoretical and percentage yield?
Actual- mass of the pure, dry product, calculated by weighing produces. Theoretical- maximum possible mass. Percentage- actual yield of the product as a percentage of the theoretical yield.
19 of 35
How do you work out the percentage yield?
Actual yield/ theoretical yield x 100
20 of 35
What is titration?
Used to check the purity of acidic or alkaline products. They work using neutralisation reactions.
21 of 35
Explain how titration works.
Add alkali to titration flask with few drops of indication.Fill burette with acid. Using burette add acid to alkali a bit at a time giving the conical flask a regular swirl to mix completely. When colourless all the alkali has been neutralised.
22 of 35
How do you use titration with solids?
Solid lump is crushed into powder. Put titration flask onto balance. Weight powder into flask. Add solvent to dissolve powder. Swirl titration flask until solid is dissolved.
23 of 35
Why is purification important?
Pharmaceuticals- Ensure drugs are for human consumption are free from impurities. Petrochemicals-Impurities or contaminants in petrol products they could cause damage to a car's engine.
24 of 35
How do you work out purity of a product`/
1. Work out concentration of solution. 2. Work out mass (mass=concentration x volume) 3. Purity= calculated mass of substance/ mass of impure substance at start x 100
25 of 35
What is an exothermic reaction?
Gives out energy to the surroundings, usually in the form if heat and usually shown by a temp rise.
26 of 35
What is an endothermic reaction?
Takes in energy from the surroundings, usually in the form of heat and usually shown by a fall in temp.
27 of 35
Why is energy management important to control?
Exothermic-heat produced needs to be removed (temp increase), rate of reaction increase if temp increase (hotter reaction), could become gases-increase pressure- explosion. Endothermic- slow down rate of reaction- mixture freeze (damage equipment)
28 of 35
What are some slow rates of reaction and fast rates of reactions?
Slow-iron rusting, chemical weathering e.g. acid rain to limestone buildings. Fast-metal reacting to acid, burning (explosions)
29 of 35
What does the rate of reaction depend on?
Temperature, catalyst, concentration, surface area
30 of 35
How does temperature increase the rate of reaction?
As all the particles move faster. The faster they move the more energy they will have so more of the collisions will have enough energy to make the reaction happen
31 of 35
How does concentration increase the rate of reaction?
If the solution is more concentrated their are more particles of the reactant going around in the same volume of water. Therefore the collisions between the reactant particles are more likely.
32 of 35
How does surface area increase the rate of reaction?
If you use a powder it has more surface area than a solid as the particles around it will have more area to work on so their will be more collisions more frequently.
33 of 35
How does using a catalyst increase the rate of reaction?
A catalyst works by giving the reacting particles a surface to stick to where they can bump into each other. This increases the number of successful collisons.
34 of 35
What are the three different ways to measure the speed of a reaction?
1) Precipitation and colour change. Time how long it takes for the paper to disappear under the glass. 2) Change in mass-spped of reaction producing gas loss in mass 3) Volume of gas given off- gas syringe (more gas in certain time faster reaction)
35 of 35

Other cards in this set

Card 2

Front

What types of chemicals do we use in day to day life?

Back

Food additives(preservatives,colouring and flavouring), cleaning and decorating products (paints contain pigments and dyes, bleach,oven cleaner, washing-up liquid) , drugs, fertilisers (ammonia)

Card 3

Front

What are the pH levels for acids and alkalis?

Back

Preview of the front of card 3

Card 4

Front

Give different types of acids.

Back

Preview of the front of card 4

Card 5

Front

Give different types of alkalis.

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all C6 resources »