3800 results found

#### "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

#### 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

#### Combustion of Alcohols Investigation.

Combustion of Alcohols Investigation PLAN Aim: To find out how much energy is required to burn enough of the following alcohols: methanol, ethanol, propanol and pentanol, in order to heat a beaker of water by 40°. The combustion of an alcohol is an exothermic reaction, meaning that more energy is given off during the process than is being taken in. by knowing the individual bond energies for each bond, we can calculate what the energy values obtained from our investigation should aspire to to be accurate. Each bond (eg. C-H, where the '-' signifies a single bond, or O=O, where the '=' denotes a double bond), have different energies. They are as follows: Bond Bond energy (kJmol-1) C-H O=O C=O H-O C-C C-O 435 497 803 464 347 358 MOLECULE DIAGRAMS The following are the reactions which occur when each alcohol combusts. METHANOL: CH3OH + 11/2 O2 CO2 + 2H2O ETHANOL: CH3CH2OH + 3O2 2CO2 + 3H2O PROPANOL: CH3CH2CH2OH + 41/2 O2 3CO2 + 4H2O PENTANOL: CH3CH2CH2CH2CH2OH + 71/2 O2 5CO2 + 6H2O Given this knowledge we can calculate how much energy should be given out per mole of alcohol that is combusted. To do this we add up the bond energies for each bond that is either broken or made during the combustion process. We then simply subtract the total energy given out from the total energy used up. We should in theory obtain a negative number from this, as

• Word count: 2518
• Level: GCSE
• Subject: Science

#### Kinetic Theory of Matter Investigation

The Kinetic Theory of Matter The main points of the kinetic theory are: . All matter is made up of tiny, invisible, moving particles. 2. Particles of different substances have different sizes. 3. Smaller particles move faster than heavier ones at a given temperature. 4. As the temperature rises, the particles move faster because the particles have more kinetic energy. 5. In a solid, the particles are a very close together and they can only vibrate about fixed positions. 6. In a liquid, the particles are a little further apart. They have more energy and they can move around each other. 7. In a gas, the particles are far apart. They move rapidly and randomly in all the space they can find. This diagram shows the particles in the three states of matter: The Collision Theory of Chemical Reactions A chemical reaction cannot happen unless particles in the reacting substances collide with each other. There are three main conditions which must be presenting order for a reaction to occur: . The reactant particles must collide. 2. They must collide at the correct orientation (e.g. a head on collision is better than a glancing blow) 3. The must collide with a minimum amount of energy, (the activation energy) to allow the rearrangement of atoms; otherwise they simply bounce of each other. Changing the Rate of a Chemical Reaction The rate of reaction is only affected if

• Word count: 2546
• Level: GCSE
• Subject: Science

#### What effect does Acid rain have on germination?

BIOLOGY COURSEWORK JENNY HODGSON 11A WHAT AFFECT DOES ACID RAIN HAVE ON GERMINATION? BACKGROUND KNOWLEDGE A seed is formed from the ovule of a flower as a result of fertilisation, and is then dispersed from the parent plant. If the seed lands in a suitable place, it will germinate. Germination is the growth of the embryo inside the seed, eventually growing into a mature plant. CONDITIONS NEEDED FOR GERMINATION OXYGEN - is used for aerobic respiration, which provides the energy for many chemical changes involved in the food reserves and making the new cytoplasm and cell walls of the growing seedling. TEMPERATURE - a rise in temperature speeds up most chemical reactions, including those taking place in living organisms. Germination, therefore occurs more rapidly at high temperatures (up to about 40 degrees centigrade). Above 45 degrees centigrade, the enzymes are denatured and the seedlings would be killed. Below 0-5 degrees centigrade, germination may not start at all. WATER - before the changes necessary for germination take place, the seed must absorb water. The water which reaches the embryo and cotyledons is used to: * Activate the enzymes in the seed * Help the conservation of starch to sugar, and proteins to amino acids * Transport the sugar in solution from the cotyledons to the growing regions WHAT HAPPENS DURING

• Word count: 2080
• Level: GCSE
• Subject: Science

#### In my investigation, I intend to find out what effect changing the concentration of sodium thiosulphate has on the rate of reaction between hydrochloric acid and sodium thiosulphate.

Plan of Experimental Procedures Preliminary Experiment Our teacher demonstrated the experiment for us. She drew an X on a piece of filter paper and placed it under a flask with sodium thiosulphate in it. She added the hydrochloric acid to the sodium thiosulphate. As the reaction occurred, the solution gradually became cloudy. We saw that the experiment ›visible. Introduction In my investigation, I intend to find out what effect changing the concentration of sodium thiosulphate has on the rate of reaction between hydrochloric acid and sodium thiosulphate. Na2S2O3 + 2HCl › S + SO2 + 2NaCl + H20 Independent Variable to be Investigated In the experiment, the independent variable will be the concentration of sodium thiosulphate. This is so I can see the effect of changing the concentration of sodium thiosulphate on the rate of reaction between the sodium thiosulphate and hydrochloric acid. Theory I predict that the rate of reaction will be directly proportional to the concentration of sodium thiosulphate solution. When the concentration is low, then there will be less chance of successful collisions between the hydrogen ions and the thiosulphate ions and so, will take longer to react. However, if the concentration of sodium thiosulphate is increased, there will be more chances for the hydrogen ions and thiosulphate ions to collide. Also, if the concentration

• Word count: 1046
• Level: GCSE
• Subject: Science

#### The Electrolysis Of Copper Sulphate Solution Using Copper Electrodes.

The Electrolysis Of Copper Sulphate Solution Using Copper Electrodes Planning I did some preliminary work to see which current values, and for how long to time. The results of this are in the tables below: Electrode-1A Mass before (g) Mass after (g) Mass change (g) Anode 1.38 1.30 -0.08 Cathode 1.35 1.65 +0.30This was done for 10 minutes. The mass lost at the anode should equal the mass gained at the cathode, which this doesn't, it has a percentage inaccuracy of 0.22¸ .30x100= 73% which is very inaccurate, This may be due to the current being too high, so the copper does not all transfer properly, but lies on the bottom of the beaker, therefore a lower current must be used, as in the table below: Electrode-0.1A Mass before (g) Mass after (g) Mass change (g) Anode 1.42 1.35 -0.07 Cathode 1.16 1.21 +0.05This was also one for ten minutes, and shows much more accurate results, as the percentage inaccuracy is only 0.02¸ 0.07x100=29%, which is still inaccurate, but is a lot better . This could be due to the current value being to low, so I will take a range of 5 results from 0.1Amp to 1Amp at 0.2Amp intervals. Each electrolysis will last 10 minutes, and each will be repeated twice so that a more accurate average can be taken. Variables * Temperature of the electrolyte * The concentration of the electrolyte * The separation of he electrodes * The size of the

• Word count: 2511
• Level: GCSE
• Subject: Science

#### Experiment To Investigate the Effect On the Rate of Reaction Caused By Changes In Temperature.

Experiment to investigate the effect on the rate of reaction caused by changes in temperature. Plan The Aim of this experiment is to investigate the effect on the rate of reaction caused by changes in temperature. Safety Safety in this case includes: * The use of a heatproof mat * Sensible setup of equipment so that the desk is clear and everything is stable * Setting the bunsen to a safety flame while it is not in use * Wearing goggles while using hydrochloric acid and sodium thiosulphate * Wearing an apron to protect clothes Fair Test To make any experiment a fair test, I must make sure that I wash and dry the apparatus after every test so that the substances do not get contaminated. Also, because the solutions are both clear it would help to use different sizes of measuring cylinder and beaker so that the two liquids can be distinguished Equipment Theory The rate of reaction is the amount of a substance that takes part in a chemical reaction in a given time. The main thing that can change the rate of reactions is a catalyst because they provide an easier path to overcoming the activation energy. Concentration also affects reaction rate. A higher concentration increases the amount of particles that can collide. If reacting substances are heated, the rate of the reaction usually rises because the particles that make up the substance already have more

• Word count: 1652
• Level: GCSE
• Subject: Science

#### To investigate the effect of the concentration of nitric acid on the rate of reaction between the nitric acid and magnesium granules.

FACTORS AFFECTING RATES OF REACTION AIM: To investigate the effect of the concentration of nitric acid on the rate of reaction between the nitric acid and magnesium granules BACKGROUND KNOWLEDGE: The equation for this reaction is: Word: Magnesium + Nitric acid Magnesium Nitrate + Hydrogen Gas Balanced Equation: The products of the reaction between nitric acid and magnesium are magnesium nitrate, water and hydrogen gas. In my main investigation, I will measure the rate of reaction by calculating the volume of hydrogen gas produced, using a gas syringe, over a certain time period. I will then plot a graph of gas produced against time for all of the different concentrations of nitric acid. Having plotted gas produced against time for each concentration, I will then take a tangent of the line produced by each concentration graph and calculate the rate of reaction for each concentration. The rate of reaction will be calculated as follows: Rate of reaction = volume of gas produced/time (cm³/second) Having done that, I will plot a graph of rate of the reaction for each concentration against concentration, and then state what type of relationship there is between the concentration of acid and the rate of reaction. I will then be able to conclude and state from my results what type of relationship my results show as explained on the following page. I will then analyse

• Word count: 5293
• Level: GCSE
• Subject: Science