# C3 Spaced Learning

C3 Spaced Learning Either measure: How fast the reactant is used up Or How fast a product is formed Units of rate depend on what you measured g/s or g/min cm3/s or cm3/min Measuring Reaction Rate The steeper the line, the faster the reaction. Horizontal = reaction has stopped. To find the rate of the reaction from the graph, 1. Find the gradient of the line. 2. Use the axis labels to work out the units. C3 The limiting reactant is the one that is all used up in the reaction. If you double the amount of limiting reactant, you double the number of particles available to make the product so,

you double the amount of product. When you increase the concentration, there are more particles in the same volume of liquid, so the particles collide more often, and so the reaction is faster. When you increase the pressure, there are more particles in the same volume of gas, so the particles collide more often, and so the reaction is faster. When you increase the temperature, the particles move faster, so the particles collide more often, And so the reaction is faster. When you increase the temperature The particles have more energy So a higher proportion of collisions are successful And so the reaction is faster. Temperature, concentration and pressure (spot the difference one answer = many questions!) Reaction rate depends on How often the reactant particles collide How much energy is transferred during the collision (whether is it successful or not.) The red line shows the most

concentrated, highest pressure or highest temperature reaction. Possible catalyst Appearance at the start Volume of gas produced in 60 seconds. (cm3) Appearance at the end None - 45 - Copper Orange/brown 80 Orange/brown Copper sulfate

Blue 98 orange/brown Magnesium sulfate White 46 white A catalyst is a substance which speeds up a chemical reaction and is unchanged at the end of the reaction. Only a small amount of catalyst is needed. Catalysts are specific to a reaction which means that a catalyst that works for one reaction might not work for another reaction. Copper is the catalyst because it speeds up the reaction and remains the same at the end. Explosions are very fast reactions that produce lots of gas. Fine combustible powders are dangerous in factories because they can cause an explosion. The red line is powdered reactant because it is

steeper = faster reaction. Surface area and catalysts When you cut a solid up into smaller pieces, you increase the surface area, so the particles collide more often, and so the reaction is faster. Find the relative formula mass of the following. The relative atomic mass, Ar of C=12, O=16, Mg=24, H=1 and Zn=65 CO2 = 12 + 16 +16 = 44 MgCO3 = 24 + 12 + 16 +16 + 16 = 84 Mg(OH)2 = 2x(16+1) +24 = 2 x 17 + 24 = 58 When you see these in a question, start by doing the adding up the formula sum. Mass is conserved in a chemical reaction. The particles that are there at the start are there at the end just rearranged. You cannot make new particles. CaCO3 CaO + CO2 Show, by calculation, that mass is conserved in this reaction. And calculate the mass of CaO produced if you start with 5g of CaCO3 The relative atomic mass, Ar of Ca = 40, C=12, O=16. Finding the relative formula masses of the reactants and products: CaCO3 = 40 + 12 + 16+16+16 = 100 CaO = 40 + 16 = 56 CO2 = 12 + 16+ 16 = 44 So products should = reactants: 100 = 56 + 44

5/100 = ?/56 ? = (5 x 56)/100 ? = 2.8g Reacting Masses Percentage yield 100% = no product lost 0% = no product made You must know the formula: % yield = actual yield x 100 predicted yield In industry As high a % yield as possible Reduces the reactants wasted Reduces cost % yield and atom economy little number big number x 100 In industry As high an atom economy as possible Reduces the production of unwanted products Makes the process more sustainable Atom economy 100% = all the atoms in the reactants are in the desired product High atom economy = greener. You must know the other formula:

Atom economy = relative formula mass of desired products x 100 sum of the relative formula masses of all products Exothermic = energy given out = temperature increases = bond making Endothermic = energy taken in = temperature decreases = bond breaking Energy In a reaction bonds are broken and made. If a reaction is exothermic, the energy needed to break the bonds is less than the energy which is given out when the new bonds are made. To compare the energy transferred per gram of different fuels. Use a spirit burner Heat a known mass of water in a copper calorimeter Measure the mass of fuel burnt Measure the temperature change Making it fair and valid Use the same volume of water, same temperature change, same height above the flame, The exam paper wont say this part, but you must stir to heat evenly. remember to use the water mass, not the fuel mass. Energy transferred (J) = mass of the water x specific heat capacity x change in temperature Energy per gram = energy transferred (J) _ mass of fuel burnt (g) You need to be able to rearrange this to find the mass or the change in temperature.

Extracting chemicals from plants: Crush Boil to dissolve in a solvent Chromatography to separate The purer the chemical, the closer the melting/boiling point will be to the pure substance. Cost of equipment Rate of production Shut down and start up times Workforce Batch Low Low Short easy to do Many people need to be trained. Ease of automation Difficult Type of product High quality chemicals, seasonal Why it is expensive to make, test and develop new pharmaceutical drugs. Research Testing to make sure they are not toxic and will do as they should. Labour costs Energy costs Raw materials Time taken for development

Marketing Continuous High High Take a long time, hard to do. Few people, no special training Easy Chemicals needed in large quantities Diamond, graphite and fullerenes are allotropes of carbon because they are all made of carbon atoms, but the atoms are arranged differently which gives them different properties Allotropes Diamond and graphite both have giant molecular structures because all of the atoms are covalently bonded together. Other giant molecular structures will have similar properties. Nanotubes are used in new drug delivery systems because the drug can be placed inside the nanotube cage to stop it damaging other parts of the body while it is delivered to a tumour. Nanotubes can be used as catalysts as they have a huge surface area for the reactants to collide with. Diamond Jewellery shiny and attractive

Cutting tools hard Does not conduct electricity All the electrons are involved in C-C bonds Is hard and has a high melting point Because the covalent bonds are all strong So they take lots of energy to break. Graphite Pencil leads slips easily off the pencil, black, Lubricants slippery High melting point because the covalent bonds are strong and take lots of energy to break. Slippery the layers slide over each other easily Conducts electricity because only three of the carbons four electrons are involved in covalent bonds so there are free electrons which can move and conduct. Either measure: Or One way we could collect the gas. Units of rate depend on what you measured Another way we could measure the reaction rate. To find the rate of the reaction from the graph, 1 2

Another way we could collect the gas Measuring Reaction Rate How do you know which is fastest? The limiting reactant is.. If you double the amount of limiting reactant. Either measure: How fast the reactant is used up Or How fast a product is formed Units of rate depend on what you measured g/s or g/min cm3/s or cm3/min To find the rate of the reaction from the graph, 1. Find the gradient of the line. 2. Use the axis labels to work out the units. Measuring Reaction Rate The steeper the

line, the faster the reaction. Horizontal = reaction has stopped. The limiting reactant is the one that is all used up in the reaction. If you double the amount of limiting reactant, you double the number of particles available to make the product so, you double the amount of product. Temperature, concentration and pressure When you increase the concentration, (spot the difference one answer = many questions!) When you increase the pressure, Reaction rate depends on 1.. 2. When you increase the temperature, When you increase the temperature The red line shows When you increase the concentration,

there are more particles in the same volume of liquid, so the particles collide more often, and so the reaction is faster. When you increase the pressure, there are more particles in the same volume of gas, so the particles collide more often, and so the reaction is faster. When you increase the temperature, the particles move faster, so the particles collide more often, And so the reaction is faster. When you increase the temperature The particles have more energy So a higher proportion of collisions are successful And so the reaction is faster. Temperature, concentration and pressure (spot the difference one answer = many questions!) Reaction rate depends on How often the reactant particles collide How much energy is transferred during the collision (whether is it successful or not.) The red line shows the most concentrated, highest pressure or highest

temperature reaction. Possible catalyst Appearance at the start Volume of gas produced in 60 seconds. (cm3) Appearance at the end None - 45 - Copper Orange/brown 80 Orange/brown Copper sulfate Blue 98

orange/brown Magnesium sulfate White 46 white A catalyst is a substance Only Catalysts are specific to a reaction which means Explain which substance is the catalyst Explosions are Fine powders are dangerous because The red line is When you cut a solid up into smaller pieces, Surface area and catalysts Possible catalyst Appearance at the start Volume of gas produced in

60 seconds. (cm3) Appearance at the end None - 45 - Copper Orange/brown 80 Orange/brown Copper sulfate Blue 98 orange/brown Magnesium sulfate White 46

white A catalyst is a substance which speeds up a chemical reaction and is unchanged at the end of the reaction. Only a small amount of catalyst is needed. Catalysts are specific to a reaction which means that a catalyst that works for one reaction might not work for another reaction. Copper is the catalyst because it speeds up the reaction and remains the same at the end. Explosions are very fast reactions that produce lots of gas. Fine combustible powders are dangerous in factories because they can cause an explosion. The red line is powdered reactant because it is steeper = faster reaction. Surface area and catalysts When you cut a solid up into smaller pieces, you increase the surface area, so the particles collide more often, and so the reaction is faster. Find the relative formula mass of the following. The relative atomic mass, Ar of C=12, O=16, Mg=24, H=1 and Zn=65

CO2 MgCO3 Mg(OH)2 When you see these in a question, start by doing the adding up the formula sum. Mass is conserved in a chemical reaction because CaCO3 CaO + CO2 Show, by calculation, that mass is conserved in this reaction. And calculate the mass of CaO produced if you start with 5g of CaCO3 The relative atomic mass, Ar of Ca = 40, C=12, O=16. Reacting Masses Find the relative formula mass of the following. The relative atomic mass, Ar of C=12, O=16, Mg=24, H=1 and Zn=65 CO2 = 12 + 16 +16 = 44 MgCO3 = 24 + 12 + 16 +16 + 16 = 84 Mg(OH)2 = 2x(16+1) +24 = 2 x 17 + 24 = 58 When you see these in a question, start by doing the adding up the formula sum. Mass is conserved in a chemical reaction. The particles that are there at the start are there at the end just rearranged. You cannot make new particles. CaCO3 CaO + CO2 Show, by calculation, that mass is conserved in this reaction. And calculate

the mass of CaO produced if you start with 5g of CaCO3 The relative atomic mass, Ar of Ca = 40, C=12, O=16. Finding the relative formula masses of the reactants and products: CaCO3 = 40 + 12 + 16+16+16 = 100 CaO = 40 + 16 = 56 CO2 = 12 + 16+ 16 = 44 So products should = reactants: 100 = 56 + 44 5/100 = ?/56 ? = (5 x 56)/100 ? = 2.8g Reacting Masses Percentage yield You must know the formula: In industry As high a % yield as possible because % yield and atom economy Atom economy 100% = High = You must know the other formula: In industry As high an atom economy as possible Percentage yield 100% = no product lost

0% = no product made You must know the formula: % yield = actual yield x 100 predicted yield In industry As high a % yield as possible Reduces the reactants wasted Reduces cost % yield and atom economy little number big number x 100 In industry As high an atom economy as possible Reduces the production of unwanted products Makes the process more sustainable Atom economy 100% = all the atoms in the reactants are in the desired product High atom economy = greener. You must know the other formula: Atom economy = relative formula mass of desired products x 100 sum of the relative formula masses of all products Exothermic = Endothermic = Energy

Explain why a reaction is exothermic overall. To compare the energy transferred per gram of different fuels. Making it fair and valid The exam paper wont say this part, but you must remember to use the water mass, not the fuel mass. Energy transferred (J) = mass of the water x specific heat capacity x change in temperature Energy per gram = energy transferred (J) _ mass of fuel burnt (g) You need to be able to rearrange this to find the mass or the change in temperature. Exothermic = energy given out = temperature increases = bond making Endothermic = energy taken in = temperature decreases = bond breaking Energy In a reaction bonds are broken and made. If a reaction is exothermic, the energy needed to break the bonds is less than the energy which is given out when the new bonds are made. To compare the energy transferred per gram of different fuels. Use a spirit burner Heat a known mass of water in a copper calorimeter Measure the mass of fuel burnt Measure the temperature change Making it fair and valid Use the same volume of water,

same temperature change, same height above the flame, The exam paper wont say this part, but you must stir to heat evenly. remember to use the water mass, not the fuel mass. Energy transferred (J) = mass of the water x specific heat capacity x change in temperature Energy per gram = energy transferred (J) _ mass of fuel burnt (g) You need to be able to rearrange this to find the mass or the change in temperature. Extracting chemicals from plants: 1. 2. 3 The purer the chemical, Batch Cost of equipment Rate of production Shut down and start up times Workforce Ease of automation Type of product Why it is expensive to make, test and develop new pharmaceutical drugs. . . . . .

. Continuous Extracting chemicals from plants: Crush Boil to dissolve in a solvent Chromatography to separate The purer the chemical, the closer the melting/boiling point will be to the pure substance. Cost of equipment Rate of production Shut down and start up times Workforce Batch Low Low Short easy to do Many people need to be trained. Ease of automation Difficult Type of product High quality chemicals, seasonal Why it is expensive to make, test and develop new pharmaceutical drugs. Research Testing to make sure they are not toxic and will do as they should.

Labour costs Energy costs Raw materials Time taken for development Marketing Continuous High High Take a long time, hard to do. Few people, no special training Easy Chemicals needed in large quantities Diamond, graphite and fullerenes are allotropes of carbon because 1. 2. 3. Allotropes Diamond and graphite both have giant molecular structures because Diamond Jewellery utting tools Does not conduct electricity Because Is hard and has a high melting point because Graphite

Pencil leads Lubricants Nanotubes are used in new drug delivery systems because Nanotubes can be used as catalysts as High melting point because Slippery Conducts electricity Diamond, graphite and fullerenes are allotropes of carbon because they are all made of carbon atoms, but the atoms are arranged differently which gives them different properties Allotropes Diamond and graphite both have giant molecular structures because all of the atoms are covalently bonded together. Other giant molecular structures will have similar properties. Nanotubes are used in new drug delivery systems because the drug can be placed inside the nanotube cage to stop it damaging other parts of the body while it is delivered to a tumour. Nanotubes can be used as catalysts as they have a huge surface area for the reactants to collide with. Diamond Jewellery shiny and attractive Cutting tools hard Does not conduct electricity

All the electrons are involved in C-C bonds Is hard and has a high melting point Because the covalent bonds are all strong So they take lots of energy to break. Graphite Pencil leads slips easily off the pencil, black, Lubricants slippery High melting point because the covalent bonds are strong and take lots of energy to break. Slippery the layers slide over each other easily Conducts electricity because only three of the carbons four electrons are involved in covalent bonds so there are free electrons which can move and conduct.

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