B3, C3, P3

1. History of the Periodic Table

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   • In the early 1800's scientists didn't know about the physical properties of elements, so the periodic table was ordered by atomic mass.
   1. Newland

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      • Newland noticed that every 8th element had similar properties so he arranged them in rows of 7, however this was widely ignored as his groups didn't all have similar properties and he didn't leave gaps for undiscovered elements.
   2. Mendeleev
2. The Modern Periodic Table

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   • The modern periodic table is arranged in order of atomic number; the number of protons or electrons in the element; therefore from the atomic number of an element you can work out the cell structure and the properties of the element. the more shields, the more shielding meaning as the period number increases electrons are easier lost and harder gained.

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• As you go down the group, increase periods, the elements become more reactive, as they are trying to lose electrons, they also have a lower melting and boiling point, the more shells they have. the Alkali metals also have a very low density and 1 outer electron, they are reactive metals and form ionic compounds with non metals and produce hydrogen when they react with water 

1. Group 1

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• The halogens are group 7 non metals, as you go down the group they get less reactive and have higher melting and boiling points. all of the halogens have coloured vapoursand exist as molecules, a pair of atoms. they produce ionic compounds with metals.

1. Group 7

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• Transition metals are good conductors, dense, strong, shiny, unreactive and have high melting points. They often have more than 1 ion, eg. FE2+(green compounds) and FE3+(red/brown compounds). They all make colourful compounds and are great catalysts.

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• Hard water is caused by calcium and magnesium ions, it causes scum and scale as the ions react with the soap to produce scum, heated hard water causes scale which reduces the efficiency. Although hard water has some benefits; the minerals in it mean that people drinking hard water have a reduced risk of heart disease. the source of the minerals is water flowing through rocks and dissolving the compounds in them.

1. Softening water

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   • there are two types of hard water; temporary, caused by hydrogen carbonate in calcium and permanant, caused by calcium sulphate. temporary hardness can be removed by boiling; boiling decomposes the hydrogen carbonate producing calcium carbonate, lime scale. Both can be softened using sodium carbonate which reacts with the calcium and magnesium to produce calcium carbonate and magnesium carbonate which is a solid. Another method of removing hardness is ion exchange columns which contain sodium ions on resin, when the calcium and magnesium move through the columns they exchange for sodium meaning that the solution has sodium in it rather than calcium and magnesium.
2. Titration

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   • Titration can be used to compare the hardness of water supplies, by slowly adding soap to samples you can see the hardness by knowing that the more soap needed, the harder the water. by then boiling the water you can see if the hardness was temopary or permanent.(more on titration node <<<<<<<<)

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• Drinking water must be good quality, untreated water can contain poisonous salts and harmful microbes. there are 4 stages of treatment; Screening which removes large items such as twigs, chemicals which make solids and microbes stick together and fall to the bottom, filtering which removes all remaining solids and finally chlorination which removes microbes.

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• A reversible reaction is a reaction in which the products can react to produce the reactants.

1. Equilibrium

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   • Reversible reactions reach an equilibrium when the amounts of reactants and products reach a point where they don't change, this is because the rate of each reaction which is dependant on temperature and pressure is exactly the same therefore they cancel each other out and their is no affect.
   1. The affect of temperature and pressure

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      • Changing the temp or pressure will change the point of equilibrium so that there is more reactant or product. Temperature affects the equilibrium as one direction is exothermic and the other endothermic, therefore the higher the temperature the more the endothermic direction will react. Pressure affects the equilibrium as one of the sides has a greater volume, therefore increasing the pressure will increase the reaction to produce the lower volume.

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• The Haber process is the process of producing ammonia for fertilizer, as the reaction of nitrogen and hydrogen to produce ammnonia is reversible, conditions must be kept so that the equilibrium is producing mostly ammonia, this is done by increasing the pressure as the ammonia has a smaller volume, the desired reaction is exothermic but the temperature is kept high to increase the rate of reaction, the reactants are recycled so rate of reaction is more important.

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• The first 3 alcohols in the homologous series are Methanol, Ethanol and Propanol, all of these are in the "OH" group and follow the general formula C(n)H(2n+1)OH. These 3 alcohols have similar properties; they are flammable and they all dissolve in water to produce a neutral solution. Alcohols can be used as fuels, ethanol is widely useda s it dosent pollute and is a renewable source.

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• carboxylic acids are acids made by oxidising alcohols so they have C,O,OH instead of C,H,H,OH. they react like any other acids and dissolve in water to produce weak acids.

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• Esters are formed from an alcohol and a carboxylic acid

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• 1 mole is the number of atoms of an element required for this element to way the same as its atomic mass in grams, for instance 1 mole of carbon-12 weighs 12 grams.

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• Energy transfer can be measured by taking the temperature of reactants before and after a reaction has taken place.

1. Fuels

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   • Fuel energy is measured by calorimetry, the process of heating water with a specific fuel in order to measure the energy released.
2. Bond Energies

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   • In order to calculate the bond energies of reactions you can work out the energy required and the energy released to see if it releases more energy than it requires (exothermic) or releases less than required (endothermic).
   1. Exothermic

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      • Exothermic reactions are reactions in which bonds are broken, this reaction gives out heat. On an energy level diagram the energy level increases initially, this rise represents the activation energy required to break bonds.
   2. Endothermic

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      • Endothermic reactions are reactions in which bonds are formed, this type of reaction takes in heat.
3. Getting Energy From Hydrogen

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   • Hydrogen and oxygen react exothermically to create water, this means energy can be produced without any pollutants, hydrogen gas can also be burnt to produce energy.
   1. Fuel Cells In Cars

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      • The car industry is developing fuel cells to be used in cars, unlike conventional fuels they don't produce harmful pollutants, only water. Although, using hydrogen in fuel cells takes up more space to store as its very explosive so cant be compressed much also producing hydrogen cannot be done in a convenient way.

1. Tests for Negative Ions

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   • Testing for negative ions such as carbonates, halides and sulphates require different tests. to test for carbonates a limewater test can be used; if the water turns cloudy then there is co2 present, this same test can be used to test for carbonates by reacting them with dilute acids in order to see if they produce co2. Halides are identified through the precipitates they form, chlorine produces white precip, bromide cream and iodine yellow. sulphates are recognised by reacting the solution with HCL and barium chloride, if this gos white then a sulphate is present.
2. Tests for Positive Ions

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   • Flame tests identify metal ions, for instance sodium gives a yellow flame and barium a green one. When mixed with sodium hydroxide metals form a coloured precipitate which can be used to identify the metal.

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• Titration can be used to work out the concentration of a solution (moles per dm^3)

1. Titration Calculations

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   • In order to work out the concentration there are 4 main staeps, firstly working out the moles of the known substance using the equation C x V, next write out the balanced equation for the reaction and then work out the moles of the known substance, and finally the concentration from the values worked out previously.

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• Osmosis is the net movement of water particles through a partially permeable membrane, this process occurs along a concentration gradient. Osmosis is the process which allows water to move into and out of cells; the tissue fluid that cells are surrounded by contains all of the stuff a cell could need, things like glucose diffuse through the cell membrane and water moves through via osmosis.

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• For all life processes to take place reactants need to be able to make it to the cells where they are needed. In photosynthesis carbon dioxide and water need to get into plant cells; the carbon dioxide diffuses into the cell whilst the water moves into the cell by osmosis.

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• When somebody breathes in, or ventilates air travel down the trachea, the bronchi and is then fed into alveoli by the bronchioles. In the alveoli oxygen diffuses into the bloodstream. when somebody breathes in the intercostal muscles and diaphragm contract meaning the volume of the thorax increases and the pressure decreases drawing air in, when you breath out this process reverses.

1. Gas Exchange

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   • Gas exchange- the job of gas exchange and the lungs is to transfer oxygen into the blood and remove carbon dioxide, this is done by millions of little air sacs called alveoli. oxygen diffuses through the thin wall of the alveoli into capillaries and carbon dioxide diffuses through the same thin wall from the capillaries.
2. Digestion

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   • Villi in the small intestine are responsible for digestion, millions of small finger like villi, each containing a network of capillaries, digest food. nutrients diffuse through 1 cell thick wall of the villi and into the network of capillaries when food travels through the small intestine.

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• Active transport is the movement of particles against a concentration gradient; root hairs are specialised to absorb water and minerals using active transport, they are long and thin cells on the surface of the plants roots, giving the plant a large surface area for absorbing water and mineral ions. active transport requires respiration and therefore energy.

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• Xylem transport water In plants; they are made up of dead cells and transport water up the plant.

1. Transpiration

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   • Transpiration is the loss of water from the plant, this is a result of evaporation of water from within the leaves, this creates a shortage of water in certain areas which has to be replaced, water is drawn up through the xylem vessels to replace it.

1. The Heart

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   • The function of the heart is to pump oxygenated blood around the body and take deoxygenated blood from the body. the two sides of the heart work independently; the right side dealing with deoxygenated blood and the left side with oxygenated. the right side of the heart pumps deoxygenated blood down the pulmonary artery to the lungs too get oxygenated, the right side also takes in deoxygenated blood from around the body from the vena cava and then pumps it out as described above. the left side of the heart deals with oxygenated blood, firstly taking blood from the lungs and to the heart through the pulmonary vein, this oxygenated blood is then pumped around the body through the aorta.
2. Blood Vessels
   1. Arteries

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      • Arteries carry blood Away from the heart, they have very thick walls compared to the hole; the lumen. they have a thick layer of muscle surrounding the lumen to make them strong and eleastic so they can stretch and maintain their shape.
   2. Veins

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      • Veins take blood back to the heart; in order to ensure the blood is moving in the correct direction they have valves. veins also have a layer of muscle but the wall is a lot thinner.
      1. Example- gas exchange in the lungs

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         • From the heart deoxygenated blood is carried by the pulmonary artery which then branches off into a network of capillaries which lead into the alveoli in the lungs, oxygen diffuses through the wall of the alveoli and the 1 cell thing wall of the capillaries, oxygenating the blood, these capillaries join into the pulmonary vein which carries the blood back to the heart.
   3. Capillaries

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      • arteries branch into capillaries and capillaries branch into veins; substances diffuse through the 1 cell thick wall of the capillaries and are then either used by cells of taken away by veins.
3. Blood
   1. Red blood cells

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      • Red blood cells carry oxygen, their large doughnut shape eans they have a large surface area and can carry more oxygen. in the lungs oxygen diffuses into the blood and mixes with the haemoglobin to become oxy-haemoglobin, in tissue this oxy-haemoglobin splits up into haemoglobin and oxygen which is released into the cells.
   2. White blood cells

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      • white blood cells consume pathogens in order to identify the antigen of the specific pathogen, when the white blood cell has identified the pathogen it produces antibodies to neutralise the pathogens and antitoxins to neutralise toxins produced by the micro-organisms.
   3. Platelets

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      • Platelets are fragments of cells, they help blood clot at wounds so that blood dosent pour out and pathogens cant get in.
   4. Plasma

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      • plasma is the liquid that all of the red blood cells, white blood cells, platelets, nutrients, carbon dioxide, urea, hormones, antibodies and antitoxins are in.

1. Saline- artificial blood

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   • Artificial blood is a blood substitute used to replace blood when somebody loses large amounts of blood, if somebody loses up to 2 thirds of their blood saline cam be used so that the remaining  red blood cells and blood can be pumped around the body giving the person enough time to produce more cells
2. Artificial hearts

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   • Artificial hearts are mechanical devices that pump blood around the body, an advantage of artificial hearts over donor hearts is that their is no chance of the body recognising it as a foreign organ and attack it. Although their are many disadvantages as parts of the device could wear out, the motor could stop and as its mechanical the blood dosent flow through it smoothly which can cause clots and therefore strokes.
3. Stents

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   • If somebody has coronary heart disease then the lumen, the hole, can be blocked by fat, this narrows the hole and can lead to heart attacks. Stents are tubes that keep the hole clear.

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• Homeostasis is the maintenance of a constant internal environment; temperature, water levels, ion content and blood sugar all need to be maintained, carbon dioxide and urea also need to be disposed of. Temperature must be controlled in order to keep enzymes working optimally, if you're too hot you will sweat to remove heat and blood will flow closer to the surface of the skin as its easier for heat to transfer to the environment. when you're cold you shiver, this requires respiration which produces heat, hairs also stand up on end to trap a layer of insulating air, blood also flows deeper and no sweat is produced. 

1. Homeostasis in the Kidneys

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   • The kidneys control ion and water content as well as removing urea, having too many ions in the blood can lead to cell damage therefore the kidneys filter out excess ions. Excess water also causes cell damage and is filtered out of the blood by the kidneys to be released in urine and sweat.

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• The kidneys filter out all of the water, ions, sugar and the urea produced by the liver from blood that flows through the kidneys, they are pushed into the bowmans capsule then the correct amount of each is diffused back into the capillary and all excess is released as urine.

1. Kidney Failure

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   • if kidneys cannot filter properly then waste substances can build up, this can be treated with dialysis machines or a kidney transplant.
   1. Dialysis

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      • Dialysis machines do the same job as the kidneys; blood flows alongside a partially permeable membrane, surrounded by dialysis fluid, this dialysis fluid has the perfectconcentration of the substances in blood , therefore because of diffusion excess of thesubstances will diffuse through the membrane until its at a healthy level, as this fluid is constantly eing pumped out it stays at the healthy concentration.
   2. Transplant

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      • a donor with a similar tissue type donates a working kidney which is either accepted by the body and the person can live healthily or it is rejected and attacked.

1. Controlling Blood Glucose

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   • Insulin and glucagon are the hormones that control glucose levels. When there is too much glucose in the blood, the pancreas releases insulin, the insulin hormone then triggers the liver to take in excess insulin and store it as glycogen. when there is not enough insulin (when the GLUCose is All GONe) glucagon is released by the pancreas which triggers the liver to turn some of the stored glycogen and release it as glucose.

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• Increasing population means that humans are taking more and more resources which we need and want from the environment. humans are also polluting the water, land and air through sewage, toxic chemicals, nuclear waste, household waste, smoke and gases. Humans are also taking up massive amounts of land from plants and animals for buildings, farming, dumping waste and quarrying for resources.

1. Climate Change

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   • climate change is the affects of human impact on the environment, it includes rising sea levels, abnormal weather patterns, specie distribution and reduced biodiversity.
2. Carbon Dioxide and the Greenhouse Effect

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   • Carbon dioxide causes the greenhouse effect if there is too much in the atmosphere. carbon dioxide and methane trap heat from the sun; this is the greenhouse effect
3. Deforestation

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   • Deforestation is the cutting down of trees and forests, this is done for many reasons, including timber, land and paper, but this also has some bad side effects, including more methane from the cattle or rice paddies now on the land, carbon dioxide released from the removal of the trees and less carbon dioxide removed from the environment by these trees, it also leads to less biodiversity meaning a lack of habitats for animal and organisms.

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• Fuels can be made from the fermentation of many natural bi-products, ethanol can be made by fermenting sugar, glucose makes ethanol carbon dioxide and energy

1. Biogas generators

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   • Biogas is made by the anaerobic fermentation of waste materials, biogas is around 70% methane and 30% carbon dioxide, in order to keep the microorganisms repiring and fermeting the waste the generators must be kept at a constant temperature. All generators have an inlet for waste, an outlet for digested material and an outlet for biogas.
   1. Batch generators

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      • Batch generators are manually loaded and used on a small scale in batches.
   2. Continuous generators

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      • Continuous generators make biogas all the time and is constantly fed with waste at a steady rate on a larger scale.
      1. Factors

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         • Cost; the continuous generator costs more as it has to be mechanically waste and material has to mechanically fed and removed constantly. Convenience; Batch generators are less convenient as Tahy have to be manually fed and cleaned. Efficiency; Gas is produced quickest at about 35 degrees C so other temperatures are less efficient. 

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• ;pThe efficiency of food production can be improved by reducing the number stages in the food chain, for instance using land to grow crops will produce a lot more biomass than feeding cattle to eat on that same crop as only 10% of the biomass eaten by cattle become useful meat. another way is to reduce the energy lost by animals, this is because this reduced the biomass used to provide enrgy for moving and heating, meaning they grow faster making it cheaper for the farmer. Another way that efficiency can also be increased is by developing new food sources, things like mycoprotein are produced artificially, they are used as a meat substitute.

1. Problems with Food Production

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   • Efficient food production involves compromises and conflict, distribution also causes problems. Overfishing is decreasing fish stocks affecting food chains, in order to control this fish quotas and net size limitations are in place to allow breeding to continue.

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• X-rays are very high frequency ionising waves, they can be used as they have the same affect on photogenic paper as light and as they are absorbed by dense material like bones, the image they project on the negative paper will only be areas without bone.

1. CT Scans

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   • CT scans use X-rays to produce images which show the density of tissue, as more denser tissue absorbs more rays the lighter areas on the photogenic paper are the denser areas of tissue.
2. Cancer Treatment

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   • As X-rays are highly ionising they destroy living cells, therefore they can be aimed at cancer cells in order to kill them. In order to minimise the damage done to normal cells the X-ray emitting source is rotated around the body so that the normal cells are not subjected to it for long, but the cancerous area which is always aimed at is damaged.
3. Precautions

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   • People who work with X-rays have to minimise the dosage of X-rays they are subjected to, in order to do this they wear lead aprons and stand behind lead screens as lead absorbs all type of radiation.

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• Ultrasound is any sound with a higher frequency than humans can hear. When ultrasound hits a change in medium it is reflected off, partial reflection, as well as moving through slightly refracted. Ultrasound imaging using partial reflection to measure the time it takes for the waves to bounce back to a detector in order to find out how far away things are.

1. Uses for Ultrasound

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   • Ultrasound can be used to diagnose heart problems, scanning fetus' and breaking kidney stones.
2. Ultrasound VS X-ray

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   • Ultrasound is safer than X-rays as ultrasound is not ionising unlike X-rays which are highly ionising. X-rays however produce much clearer images, sometimes 3D renderings whilst ultrasound typically produces fuzzy images.

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• Refraction occurs when light hits a change in density, as well as changing direction it also slows down and some of the light reflects. The refractive index of an object is the ratio of the speed of light in a vacuum to the speed of light in that object.

1. = sini/sinr

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   • "i" is the incident ray and "r" is the refracted ray, therefore in calculations you can use these to work out the refractive index of materials. 

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• There are two types of lenses; converging and diverging, they both work oppositely.

1. Convex Lens

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   • A convex lens is a lens characterised by its oval shape, as shown above it causes parallel rays of light to converge at a focal point, as shown above. 
2. Concave Lens
3. Images

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   • Concave images produce virtual images and convex images produce can produce real and virtual images, depending if the object is further than the focal length or not.

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• The eye focuses on things using the cornea and lens which are both convex lens', the eye can only focus on things between the far and near point of human vision, the closer something being focused on is, the more powerful the lens has to be to focus on it.

1. Correcting vision

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   • Short sightedness is where the light focusses before the retina therefore the light needs to be diverged more therefore a concave lens is used to correct the vision. Long sightedness is where the light focusses after the retina, to fix this a convex lens is used to focus the light earlier; on the retina. A laser can also be used to change the shape of the lens to change its power, increasing its power corrects long sightedness and decreasing its power corrects short sightedness.

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• A moment is the turning force of an object, calculated by Force x Distance, therefore using a longer spanner for example would increase the turning effect on the nut.

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• The centre of mass is always directly below the point at which the object is suspended, this is because the centre of mass is the point at which all mass is equal in every direction.

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• In order for an item to balance, the two moments that act either side of a pivot must be equal. Force multipliers increase the distance in order to decrease the force required to increase the moment

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• A moment is force X distance, if moments are not equal then an object is not stable. low and wide objects are more stable as the centre of mass is more likely to be over the base.

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• Hydraulics is about the properties of liquids; liquids are very difficult to compress, they spread pressure abut a body of water meaning that if pressure is applied in one place it is exerted equally everywhere.Hydraulic systems work by putting force on one piston and having that force be displaced onto another through water. As Force = pressure X area so increasing the area of one piston, increases the force exerted onto the other.

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• Circular motion occurs when an object is moving in a circle, in this case the objects velocity is constantly changing as velocity is speed in a certain direction. The object is constantly accelerating towards the centre of the circle, this acceleration is caused by a centripetal force, from tension, friction or gravity.

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• A magnetic field is the area around a magnetic object that experiences a force, wires carrying current also have a magnetic field. Electromagnets are magnets which can be turned on and off by removing the current,

1. The simple Electric Motor

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• Convex lens' are used to magnify, if an object is closer to the convex lens than the focal length then it will create a virtual image that's larger than the object. The formula for the magnification of an object is image height/ object height.

1. Power

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   • The more powerful a lens the more it will converge light and the smaller the focal length