Presentation on theme: "C1 Revision. Food additives. Make food look and taste better, and last longer. Anti-oxidants stop the food from reacting with oxygen. Emulsifiers help."— Presentation transcript:
Food additives. Make food look and taste better, and last longer. Anti-oxidants stop the food from reacting with oxygen. Emulsifiers help oil and water mix. –Hydrophobic and hydrophilic. The E means it has passed a safety test, the number tells you what it does.
Cooking. Proteins denature. –Heat changes their shape permanently. Starch grains burst. Cooking is an irreversible chemical change. NaHCO 3 → Na 2 CO 3 + CO 2 + H 2 O
Perfume. Acid + Alcohol → Ester and Water. –Easily evaporates. –Non toxic. –Doesn't react with water. –Doesn't irritate your skin. –Insoluble in water.
Solutions. A solute dissolves in a solvent making a solution. Its all about attraction. –The solvent needs to be able to break the bonds of the solute and make stronger bonds with them.
What is oil made of??? Oil is a Mixture of Hydrocarbons They are called: Alkanes and Alkenes
Chemicals Name chemical formula display formula 3d shape. methane, CH 4 C H H H H
An example of an alkane Methane All single bonds Saturated
an example of an alkene Ethene Contains a double bond unsaturated
Alkanes and alkenes. Alkanes: –C-C –‘saturated‘ –C n H 2n+2 –Can’t make polymers. –Very unreactive. –Does nothing to bromine water. Alkenes: –C=C –'unsaturated' –C n H 2n –Used to make polymers. –Very reactive. –Turns bromine colourless.
Fractional distillation. Hydrocarbon molecules contain only carbon and hydrogen atoms. Crude oil can be separated by fractional distillation, –because they have different boiling and condensation points. The crude oil is heated to vapourise it (evaporated or boiled). The most volatile fraction, i.e. the molecules with the lowest boiling points, boil or evaporate off first and go to the top of the column.
How do we separate this mixture?? Fractional Distillation As you go up the column to the: –Boiling point decreases –Intermolecular forces decrease –Volatility/ignition increases
Hydrocarbon Bonds. Down the pic above the molecule gets...... bigger as the carbon atom number in the molecule increases.... more viscous as the intermolecular forces between molecules increases.... higher melting point as more energy is needed to overcome the intermolecular forces holding the molecules together.... higher boiling point as more energy is needed to overcome the increasing intermolecular forces between the liquid molecules.... less flammable as they become less volatile, again due to increasing intermolecular forces.
How do we make the fractions more useful?? What process is used to break long carbon molecules (like tar) into smaller, more useful molecules (like petrol)? Cracking Need a catalyst High pressure
Cracking. In the catalytic cracker long chain molecules are split apart or ‘cracked’. This is another example of thermal decomposition. C 8 H 18 C 6 H 14 + C 2 H 4 + ethene Octane hexane Ethene is used to make plastics Heat pressure catalyst Used as a fuel
Polymers. Monomers stick together and make polymers. Unsaturated monomers have a double bond between 2 carbons. HH CC H HH HH C C HH HH CC HH HH CC HH HH CC HH And lots more.. addition polymerisation This is called addition polymerisation and is written as: Pressure high temperature catalyst n n ethene poly(e)thene 1 2 3 4 5 thousands CC H H H H CC H H H H C C HH HH
Making Polymers What do we start with??? An AlKENE
Making Polymers The DOUBLE bond is broken leaving:
Polypropene polymerisedEthene is only one alkene. Other unsaturated molecules such as propene, vinyl chloride and styrene can also be polymerised to produce a range of plastics. E.g. propene Poly(propene) n n propene
pvc CC HH H Cl n n Vinyl chloride CC Cl H HH PVC
Fuels. Oil is running out, and is none renewable. Oil slicks, acid rain, and green house problems. Things that are important about choosing fuels are: –How much energy it gives out. –How much it costs. –How easy it is to store. –How poisonous it is. –How much pollution it gives off.
Burning fuels. Burning hydrocarbons always gives off water vapour. Enough oxygen allows complete combustion giving off carbon dioxide as well. Too little oxygen gives off carbon monoxide instead (and less oxygen). Cobalt blue goes pink for water Lime water goes cloudy for carbon dioxide.
Burning hydrocarbons The apparatus below is used to test the products of combustion of a hydrocarbon. any hydrocarbon + oxygen water + carbon dioxide Suction pump Candle wax is the hydrocarbon here ice- water Liquid collected can be tested with anhydrous cobalt chloride paper (blue pink). Lime water
Incomplete Combustion of Alkanes In the absence of an adequate supply of air, alkanes may react to form carbon monoxide and water. Carbon monoxide is highly poisonous and this is one reason why gas boilers must be serviced regularly. Methane + oxygen water + carbon monoxide 2CH 4 + 3O 2 4H 2 O + 2CO A carbon monoxide detector
Energy. Exothermic –Gives out energy –More bonds are made than broken Endothermic –Takes in energy. –More bonds are broken than made. It takes 4.2 Joules of energy to increase the temp of 1g of water by 1C Energy transferred (J) = mass of water (g) x 4.2 x temp change (C) Energy of fuel (J/g) = energy transferred (J) / mass of fuel burnt (g)
Energy for the Home Module P1 Revision The thermal energy in a mass is the total energy of all the particles in the mass Thermal energy (heat) is measured in joules (J) The temperature is a measure of how hot something is (how fast the average particle is moving) Temperature is measured in degrees Celsius (°C)
Like water flowing downhill, from higher places to lower places Thermal energy transfers from high temperature places to low temperature places The bigger the temperature difference the quicker the heat energy transfers
The Thermogram Temperature is shown by the colour Hot = red/yellow Cold = blue
Heating and Cooling To raise the temperature of an object energy must be added (by heating it) To lower the temperature of an object energy must be taken away (by cooling it)
Specific Heat Capacity, SHC The amount of energy added or subtracted to change the temperature of a substance depends on: Its mass The material The temperature change
Specific Heat Capacity, SHC The Specific Heat Capacity of a substance is the energy needed to change the temperature 1 kg of the substance by 1 o The greater the SHC the more heat energy it can store
Specific Latent Heat, SLH When a solid melts or a liquid boils it requires energy, even though its temperature does not change The energy is needed to break the bonds between the molecules
Specific Latent Heat, SLH When a liquid solidifies or a gas condenses energy is released even though the temperature does not change The energy is released as the atoms or molecules join together and slow down
Specific Latent Heat, SLH The Specific Latent Heat, SLH, is the energy required or released by 1 kg of a substance when it melts or freezes, evaporates or condenses
Insulation Air is a good insulator, (all gases are good insulators) Any material that traps pockets of air is a good insulating material Eg: Expanded polystyrene, fibreglass wool, Double glazing, feathers, fur
Insulating the house Loft insulation Cavity Wall insulation Double glazing Carpets Draught excluders
Payback time Payback time = Original cost ÷ annual saving
Efficiency The more efficient a machine or device is, the more of its INPUT energy is transferred into a USEFUL energy OUTPUT 100 J Electrical Energy INPUT 90 J Light Energy USEFUL OUTPUT 10 J Heat Energy WASTED OUTPUT Efficiency = 90/100 = 0.9 = 90%
Payback time Money spent on insulating your home is money well spent – but some methods are better than others: Loft insulation may cost £500 to buy, and save £250 each year in heating costs So it would take 2 years to save the original cost: Payback time is 2 Years
Heat Energy Transfer (1) CONDUCTION:- Transfer of Thermal Energy via particle to particle, atom to atom –Mainly occurs in solids –“Hotter” Particles/atoms vibrate faster, taking up more space so the solid expands –Best conductors are metals, due to free electrons enabling rapid transfer of energy
Heat Energy Transfer (2) CONVECTION:- transfer of heat energy through liquids and gases –“Hotter” particles/atoms move faster, so they take up more space and the gas or liquid expands and becomes less dense –“Hotter,” less dense, masses of water or air will rise –“Colder”, more dense, masses of water or air will sink CONVECTION CURRENTS will develop, transferring energy everywhere else
Heat Energy Transfer (3) RADIATION:- EVERY object that is HOTTER than its surroundings will emit heat energy as INFRARED RADIATION until it is the same temperature as its surroundings This can be seen by infrared cameras and sometimes felt by the skin
INFRARED (1) Black surfaces absorb infrared best –Black cars get hot in the sun, white ones stay cool Black surfaces emit infrared best –Radiators should be black – but who wants black radiators? White/silver surfaces reflect infrared –NEWS FLASH! Space tourists travel to the sun behind a giant mirror and survive! White/silver surfaces emit least –So why is my radiator white?!
INFRARED (2) USED FOR: –Burglar alarms: “heat sensors” detect infrared –Cooking: infrared heats the surface of food, cooking it –Control: Remote controls for TVs, videos, DVDs –Information: transfer of data to/from computer mouse
MICROWAVES Have longer wavelength (lower frequency) than infrared, so transfer less energy. Are reflected by metals, but go through plastics and glass Used by mobile phones, satellites and radar One particular wavelength used for cooking because it is absorbed by water molecules which then move more quickly (ie they get “hotter”) – this then cooks the food
ANALOGUE SIGNALS These are waves that continuously vary They can have many different values Any interference can not be removed: signal quality can only get worse
DIGITAL SIGNALS These are waves that only have two values: –High/Low 1 or 0 On/Off Interference or distortion can be removed or is not recognised by the receiver Signals can be boosted or amplified without increasing interference
DIGITAL SIGNALS Surface of DVD disc Digital signal Computer Binary Code
WAVES in general Wavelength Amplitude Frequency = number of cycles (0scilations) per second (Hertz) Speed of wave (m/s) = wavelength (m) x frequency (Hz)
Wave Characteristics There are two main types of wave –Longitudinal, e.g. Sound, P-waves –Transverse, e.g. Light, S-waves Energy flow Vibrational direction Transverse WaveLongitudinalWave
Wave Characteristics All waves can be REFLECTED The angle of reflection = the angle of incidence
TOTAL INTERNAL REFLECTION Optical fibres can carry signals without losing as much energy Signals are more secure: more difficult to listen in
Wave Characteristics All waves can be REFRACTED Because light SLOWS down in more dense materials like glass
Wave Characteristics All waves can be DIFFRACTED When a gap or obstacle is the same width as the wavelength the waves spread out through it, or around it When the wavelength is smaller the spreading is less obvious
ELECTROMAGNETIC WAVES Electromagnetic waves are transverse At the lowest energy, lowest frequency and longest wavelength are radiowaves Next come microwaves, infrared, visible, ultraviolet, x-rays At the highest energy, highest frequency and shortest wavelength are gamma rays
LASERS Laser light consists of lightwaves that are all in phase with each other This makes a tight beam with great intensity Can be used to cut wood, steel and flesh with great accuracy Reflects precisely off CD and DVD discs
Wireless Technology Transmitter and receiver do not need to be physically connected Available 24/7 Radio waves can be reflected around the world through the IONOSPHERE (a layer of ionised air high in the atmosphere)
Wireless Technology Microwaves can be sent around the world by being RECEIVED and RE-TRANSMITTED from geostationary satellites Microwaves can be transmitted from phone mast to phone mast if in line of sight NOT TO SCALE
INTERFERENCE Different TV and radio channels use different frequencies to broadcast their programs If these frequencies are nearly the same the receiving TV or radio will get both programs – this is INTERFERENCE
SEISMIC WAVES : P-WAVES P-Waves = Primary waves = “Pressure” waves = longitudinal waves Are transmitted through solids, liquids and gasses The denser the substance the quicker they travel Sound travels at –330m/s in air1500m/s in water5000m/s in steel
SEISMIC WAVES : S-WAVES S-waves = Secondary waves = “sideways” waves = transverse waves Only travel through solids or semi solid material Travel more slowly through the Earth than P- Waves
Structure of the Earth This is what the interior looks like – we think! But how do we know?
Structure of the Earth If the Earth was simply solid all the way through –Then the waves from an earthquake would be felt everywhere around the world
STRUCTURE OF THE EARTH What the S-Waves tell us Observation: The S-Waves are not detected over nearly half of the Earth Explanation: The waves are blocked by a Liquid Core
STRUCTURE OF THE EARTH What P-Waves tell us Observation: There is a shadow zone where P-Waves are not detected Explanation: A liquid core causes refraction of the waves
ULTRAVIOLET RADIATION UV radiation can damage DNA in skin cells Small amounts cause tanning Large amounts may cause skin cancer Dark skin absorbs some UV reducing the amount reaching the deeper layers of skin The OZONE layer absorbs some UV reducing the amount reaching the Earth’s surface CFCs reduce OZONE, CFCS have been banned from current use
CLIMATE CHANGE The Earth’s climate changes naturally as the sun changes Volcanic dust and ash and man- made pollution can reflect sunlight away – cooling the planet Greenhouse gases “trap” heat in – warming the planet Greenhouse gases include CO 2, Methane and Nitrous Oxides (NOXs)
That’s all folks Remember –Read the question at least twice, or until you understand what it is asking you –If the question asks you to “Describe...” or “Explain…” then write a complete sentence for each mark that can be given –Read through your answers to make sure that they make sense –Nonsense award Examiners marks cannot for!
FATIGUE When we do hard exercise, we respire ANAEROBICALLY and LACTIC ACID builds up in our muscles.
ANAEROBIC RESPIRATION Respiration without oxygen! Glucose lactic acid + energy MUCH LESS ENERGY RELEASED IN ANAEROBIC RESPIRATION
BALANCED DIETS Vary depending on age, gender and amount of activity Carbohydrate – The body’s energy resource Fat – An insulator and an energy resource Protein – For growth and repair Vitamins – Keep the body functioning Minerals – Keep the body functioning Fibre – Keeps food moving along the gut
Can you remember the food types and what they are needed for? Carbohydrate – The body’s energy resource Fat – An insulator and an energy resource Protein – For growth and repair Vitamins – Keep the body functioning Minerals – Keep the body functioning Fibre – Keeps food moving along the gut
CARBOHYDRATES Are made from… SIMPLE SUGARS (E.G. GLUCOSE)
Animal proteins are known as ‘first class’ proteins… …because they contain all the essential amino acids the body needs. Lack of protein causes KWASHIORKOR
BMI (body mass index) = mass (g) (height (m)) 2 BMI can be used to help us understand whether a person is underweight, normal, overweight or obese
A desire for perfection, low self-esteem and poor self image can lead to a poor diet and increased risks of poor health.
DIGESTION Chemical digestion is the break down of large insoluble food molecules into smaller more soluble ones by enzymes for absorption into the blood plasma or lymph. CAN YOU MEMORISE IT? Chemical digestion is the break down of large insoluble food molecules into smaller more soluble ones by enzymes for absorption into the blood plasma or lymph.
FOOD MOLECULES ARE BROKEN DOWN BY SPECIFIC ENZYMES.
Diseases and disorders can be caused by: Infectious microbes Genetic inheritance Vitamin deficiency Mineral deficiency
DEFICIENCIES No vitamin C Scurvy No iron Anaemia BODY DISORDERS Inability to control blood sugar level diabetes GENETIC DISORDERS Red – green colour blindness
Diseases like MALARIA are caused by PARASITES. MALARIA is spread when the parasite is carried from person to person by a mosquito (the vector). How can knowledge of how vectors spread disease help to control infection
Immunity to disease Active: –The body remembers a pathogen invasion and white blood cells can respond quickly next time it happens! Passive: –Injecting a person with antibodies (e.g. Protection from a snake bite)
The immune response The body’ white blood cells produce antibody, specific to the pathogen
What are the effects of the following types of drug? Depressants Hallucinogens Painkillers Performance enhancers Stimulants
Depressants – slow down brain function Hallucinogens- change what a person sees/hears Painkillers – Stop nerve impulses so no pain is felt Performance enhancers – develop muscles Stimulants – speed up brain function
The effects of drinking alcohol Do silly things Easily lose balance Find it hard to talk clearly Liver cirrhosis Drink driving
The effects of smoking tobacco Nicotine is addictive Carbon monoxide reduces oxygen absorption Particulates collect and block lungs Tar causes lung cancer
TOO HOT – HYPERTHERMIA (NORMAL BODY TEMPERATURE IS 37 DEGREES CELCIUS) TOO COLD - HYPOTHERMIA
Female sex hormones, progesterone and oestrogen, are produced in the ________ The male sex hormone, testosterone, is produced in the ________ The pancreas produces the hormone _______, which controls blood sugar level ovaries testes insulin
The genetic code is a set of instructions that provide each organism with its characteristics
DNA is a double helix It looks like a twisted ladder The rungs of the ladder are made up of 4 bases.