#### "Finding out how much acid there is in a solution"

Anna Galloway As Level Investigation "Finding out how much acid there is in a solution" PLAN I will carryout an acid-base titration to determine the concentration of hydrochloric acid (HCl); I will do this by making up a solution of sodium carbonate (Na2CO3) of known molarity. I will then citrate the unknown molarity of acid into the sodium carbonate; from these results it will enable me to calculate the molarity of the unknown acid. The reaction: Sodium carbonate + hydrochloric acid sodium chloride +water + carbon dioxide Na2CO3(aq) + 2HCl(aq) NaCl(aq) + H2O(l) + CO2 Planning to make the sodium carbonate solution: I already know that the approximate concentration of the hydrochloric acid is around 0.2mol/dm, from the above balanced chemical equation I know that 2 moles of hydrochloric acid react with 1 mole of sodium carbonate; therefore I will make a solution of sodium carbonate of 0.1 mol/dm^3. Half that of the approximate molarity of the hydrochloric acid, I have made it 0.1 mol/dm^3 so to keep the volumes of solutions being titrated of a sensible amount as regard to the size of glass wear available. Calculations: Sodium carbonate salts relative formula mass: Na2CO3 . 10H2O = 106 . 180 = 286 N.B there is 1 mole of sodium carbonate crystallised with 10 moles of water in this Salt Volume of sodium carbonate required per

• Word count: 1777
• Level: GCSE
• Subject: Science

#### "Making an Electromagnet"

Project in Physics Technical Paper "Making an Electromagnet" Submitted by: Group 10 Audrey Mae Selda Ednard La Rosa Easter Cindy Mutia Ken Bjanli Te Year 4- Diamond Submitted to: Ms. Shella Mae Cascaro Physics Teacher Date of Submission: December 14, 2005 Wednesday A. Statement of the Problem/ Objectives: The following are some objectives or what the proponents would like to carry out in the progress of this project: To be able to make an electromagnet in the simplest way. To be able to relate the number of turns of wire with the strength of the electromagnet To be able to attract as many paper clips as possible. To be able to explain and recognize the principles and concepts behind electromagnetism. B. Materials and Methods: I. Materials: These are some of the materials used by the proponents in making the electromagnet: One iron nail Stranded copper wire One or more D-cell batteries Scissors Paper clips II. Methods: These are what the proponents did in making the electromagnet: The proponents first gathered all the materials needed for the making of the electromagnet. The next thing that the proponents did was to remove some insulation. So a pair of scissor or a cutter was used in order to remove the insulating rubber starting from each end of the wire to expose the copper wire. The wire was wrapped around the nail in a spiral manner.

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• Word count: 1186
• Level: GCSE
• Subject: Science

#### The topic of which I have been studying is energy transfers, how energy can not be destroyed but only changed into another such as potential into kinetic, this the energy transfer which shall take place in my investigation.

Science Course Work Introduction The topic of which I have been studying is energy transfers, how energy can not be destroyed but only changed into another such as potential into kinetic, this the energy transfer which shall take place in my investigation. The aim of this investigation it to find out how the height of the ramp affects the speed the ball travels. Plan I am going to investigate how the height of a ramp affects the speed of which a ball travels. To make sure my test is correct I will need to keep several things the same these are: The distance the ball has to role, to get the speed. The length of the ramp. The ball, so that is the same mass and the surface so that the texture of it will be the same. The thing I will be changing is the height of the ramp. To do this I will use a ramp, a bouncy ball, a meter ruler, a stop watch and a clamp. All these will be provide by school. I will start by raising the ramp at 0.20 meters intervals using the clamp, starting at 0.20 meters and finishing at 1 meter. First I will mark a meter on the bench from where I will hold the ramp. After I have measured the 0.20 meters height I will roll the bouncy ball down the ramp and time it once it has reach the foot of the ramp and stop the stopwatch once the ball has reached the meter mark. I will do this three times so that my results are accurate and then find my

• Word count: 1813
• Level: GCSE
• Subject: Science

#### "The Biological Perspective"

"The Biological Perspective" The relationship between mind and body, and the influence of heredity on human behaviour are two main objectives of the biological approach to psychology. Before the concept of the brain being the seat of the soul was introduced, the vital organs of the human body were considered to be the heart and the liver,a point of view widely accepted amongst the inhabitant of incient Egypt. The theory of the brain being the seat of the soul was introduced by Alcmacon and later confirmed by Plato. Hippocrates emphasized that the brain was organ of intellect and controlled senses and movement, he suggested that a mental or behavioral disorder could be caused by physical dysfuntion and not possesed by evil spirits. Dualism was an assumption put forward by Descartes, it was a rather radical idea. The theory dualism implied the distinction of mind and body, and that the two of them could interact(via the pineal gland in the brain). But dualism was rejected by today's researchers in the biological approach because of another theory called Materialsm. The assumption that all behaviour has a physical basis. In 1745 a French phisician wrote a book called "The Natural History of the Soul" which was based on the fact that body is not just a machine, the soul is not different from the mind and that the mind was part of the body. Evantually In 1981, the view of

• Word count: 962
• Level: GCSE
• Subject: Science

#### I chose to do my sensors project about sliding potentiometers because they are very common in every day life, and I thought it may be interesting to discover how they work.

Physics coursework Introduction I chose to do my sensors project about sliding potentiometers because they are very common in every day life, and I thought it may be interesting to discover how they work. There are potentiometers on lots of everyday household appliances, sliding and rotary potentiometer on hi-fis to change the volume or tuning, washing machines and dishwashers to change settings and other electrical equipment and machine. As the world becomes more computer reliant sensors will be used more often, especially potentiometers as they are easy to operate. Rotary and sliding potentiometers both work in a similar fashion. As the slider gets moved along, the voltage increases as the potential difference changes. A rotary potentiometer works the same way, but is twisted round, so rather than measuring displacement, degrees are considered. I will take this simple idea and look into true values and patterns. Plan Fig 1. Circuit diagram of the circuit to be built.(Not to scale) I am going to build the diagram as shown above and slide the potentiometer along and see what the different readings of the voltmeter are. The equipment I shall be using is: * Wires x 4 * A 59mm sliding potentiometer (5kB) * A digital voltmeter, Rapid 212 DMM. Reading error: 0.005V * 30cm Ruler. Accuracy: 0.5mm * Stopwatch, Unilab Accuracy: 0.005 secs * Power Pack (1kWIN L.V power

• Word count: 1616
• Level: GCSE
• Subject: Science

#### I chose to investigate the behaviour of woodlice in a wet or dry environment.

David Bennett 1DSM Coursework: Behaviour of Wood Lice When Offered a choice Between Wet and Dry In the experiment I was offered the choice to investigate the behaviour of woodlice in a wet or dry environment or a light or dark environment. I chose to investigate the behaviour of woodlice in a wet or dry environment. Woodlice belong to the biological class crustacea. Most of the animals in this class are aquatic, and though the terrestrial species can breathe with the aid of primitive 'lungs' they lack the features found in most other land-dwelling arthropods. They have no waterproof waxy cuticle on their exo-skeleton and are therefore more likely to suffer from dessication compared with other arthropods such as insects which have a well developed waxy layer. These animals excrete their nitrogenous waste as ammonia gas directly thorough their exo-skeleton (rather than as urea or uric acid).This means that their exo-skeleton needs to be permeable to ammonia and is therefore also permeable to water vapour. In my experiment I am testing whether the woodlice prefer the environment to be wet or dry. I predict that they will prefer it wet rather than dry. I think this because when you find them in the wild, they are in dark damp places like under big rocks or a log. Method First of all in my experiment I will set up a 'choice chamber' with wet cotton wool under one side

• Word count: 917
• Level: GCSE
• Subject: Science

#### Characteristics of Different Soil Types

Characteristics of Different Soil Types Sand, Loamy sand, Sandy loam These are well drained and aerated and workable for most of the year. They are very light to handle and quick to warm up in spring. Unless they have a very high organic matter content they are prone to drying out too quickly, and additional watering will be needed. This extra watering will also help to wash out the plant foods and lime from the soil, so they are likely to be acid (except for some coastal soils). They are often referred to as "hungry" soils and need lots of extra feeding. With careful management however, they can be amongst the most productive soil types. Medium loam, Sandy clay loam, Silt Loam These are the "average" soil types. They achieve a good balance between the ability to be very productive and the minimum of attention. The medium loam group is probably the best in this respect. Clay, Sandy clay, Clay loam, Silty clay loam, Silty clay, Silt Although these soils are difficult to work and manage, they usually have good supplies of plant foods and lime. The main drawbacks are the high water holding capacity (which means they are late to get going in spring) and the effort required to work them. You will need to catch just the right weather conditions to avoid hard work and damage to the soil structure. The use of heavy machinery (and especially rotavators) should be avoided at

• Word count: 2337
• Level: GCSE
• Subject: Science

#### To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and the potato chip.

Amy Grammer 11.6 AT1 Aim: - To investigate the effect of varying concentration of a certain sugar solution on the amount of osmotic activity between the solution and the potato chip. Background information If a dilute solution is separated from a concentrated solution by a partially permeable membrane, water diffuses across the membrane from the dilute to the concentrated solution. This is known as Osmosis. A partially permeable membrane is porous but allows water to pass through more rapidly than dissolved substances. Since a dilute solution contains, in effect, more water molecules than a concentrated solution, there is a diffusion gradient that favours the passage of water from the dilute to the concentrated solution. In living cells, the cell membrane is partially permeable and the cytoplasm and vacuole (in plant cells) contain dissolved substances. As a consequence, water tends to diffuse into cells by Osmosis if they are surrounded by a weak solution, e.g. fresh water. If the cells are surrounded by a stronger solution, e.g. salt water, the cells may lose water by Osmosis. Water Potential. The water potential of a solution is a measure of whether it is likely to lose or gain water molecules from another solution. A dilute solution, with its high proportion of free water molecules, is said to have higher water potential than a concentrated solution, because

• Word count: 4022
• Level: GCSE
• Subject: Science

#### Area & Volume Exploration &#150; Component proportional changes

Area & Volume Exploration - Component proportional changes Question 1: How do the Volume, Surface Area and Mass of your component vary when two key dimensions are changed but the length remains the same? Changing one key Dimension by 5%, 10% & 20% Increasing the length: 20m 5% increase => 20 ? 5% = 1 100 => 20m + 1m (increase) = 21m So... New cuboid dimensions = Length = 21m Width = 10m Height = 5m Volume = 10m ? 21m ? 5m = 1050m3 S. Area = (2?10?5)+(2?21?5)+(2?10?21) = 100 + 210 + 420 = 730m3 Mass = 7800kg/m3 ? 1050m3 = 8'190'000kg This clearly shows that when the length is increased by 5% the Volume and Mass are also increased by 5%. This indicates that the Volume and Mass are directly proportional to the length. The Surface Area would not appear to be directly proportional to the length as it does not increase by 5%. Further exploration is needed to confirm that this proportional increase is not a one off event. I predict that the same will happen and the percentage increase will be the same for Length, Volume and Mass. 10% increase => 20 ? 10% = 2 100 => 20m + 2m (increase) = 22m So... New cuboids dimensions = Length = 22m Width = 10m Height = 5m Volume = 10m ? 22m ? 5m = 1100m3 S. Area = (2?10?5)+(2?22?5)+(2?10?22) = 100 + 220 + 440 = 760m3 Mass = 7800kg/m3 ? 1100m3 = 8'580'000kg Volume = 10m ? 27m ? 5m = 1350m3

• Word count: 908
• Level: GCSE
• Subject: Science

#### Rates of reactivity.

Introduction Rates of reactivity The rate of reaction is simply how fast it takes for a complete reaction to occur. In this coursework the following factors will be investigated to discover whether or not they affect the rate of reaction: * Surface area of reactants. * The temperature of reactants. * The concentration of reactants. * The involvement of a catalyst in a reaction. Collision Theory This states that reactions only commence when reacting particles collide with each other with a sufficient amount of energy, the minimum amount of energy. When the temperature of the reactants is increased particles absorb energy and move around a lot faster. This increases the chance of collisions. Increased concentration leads to more reactive particles and therefore more chance of collisions, increasing the rate of reactivity. Small pieces of reactants mean a large surface area. This allows more collision to take place resulting in a faster rate of reaction. Catalysts allow particles to react with a lower amount of energy. They also provide a surface for the particles to attach to; therefore the chances of collisions are higher. What is meant by rate of reaction? Magnesium + Hydrochloric Acid Magnesium Chloride + Hydrogen Mg (s) + 2HCl(aq) MgCl2 (aq) + H2 (g) In order for the magnesium and acid particles to react together, they must have the following bullet

• Word count: 8024
• Level: GCSE
• Subject: Science