1311 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

#### 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

#### "Examine the impact that weathering has had on human activity."

Teacher: Mr Lee, Physical Geography, Joshua Malina 11/12/04 Essay title: "Examine the impact that weathering has had on human activity." Weathering has impacted human activity in a variety of ways. There are both positive and negative aspects of the result of weathering. Firstly, the negative impacts are to be discussed. Weathering often seems to be at a higher rate in urban areas than that of rural areas due to the large volumes of gases and pollution given out by industries and vehicles. When coal and oil are burnet sulphur dioxide is releases and when it combines with water vapour in the air dilute sulphuric acid is the product. Nitrogen oxides combine in a similar way to produce nitric acid. The result is acid rain. The acid rain chemically weathers materials away by decomposing the minerals. London is widely known for burning large doses of fossils fuels increasing the amount of acid rain. This rain has then fallen on buildings such as St. Paul's Cathedral and increased chemical weathering leading to deterioration on its surface. Also, if cracks and joints present will have allowed this rain to enter and chemically weather there as well as on the surface. This chemical weathering has also been enhanced due to the extremely large presence of birds in the area, particularly pigeons whose faeces contribute to the chemical weathering. Very recently this has had

• Word count: 913
• Level: GCSE
• Subject: Science

#### Investigating antacids.

Investigating antacids Aim: To discover the most effective and useful base for use as an antacid using both chemical and medical evidence to make a final judgement. The formulae for the neutralisation of each base are as follows: Mg(OH)2 + 2HCl › MgCl2 + 2H2O Mr: 92 + 80 = 172 0.2g + 1.8g = 2g 0.0022 + 0.0225 CaCO3 + 2HCl › CaCl2 + CO2 + H2O Mr: 100 + 80 = 180 0.2g + 1.8g = 2g 0.0020 + 0.0225 MgCO3 + 2HCl › Mg(Cl)2 + CO2 + H2O Mr: 84 + 80 = 164 0.2g + 1.8g = 2g 0.0023 + 0.0225 MgO + 2HCl › MgCl2 + H2O Mr: 40 + 80 = 120 0.2g + 1.8g = 2g 0.005 + 0.0225 NaHCO3 + HCl › NaCl + CO2 + H2O Mr: 84 + 37 = 71 0.2g + 0.9g = 1.1g 0.0023 + 0.0243 We are using 0.5M Hydrochloric acid for the titration and we would therefore expect that 0.9g of HCl is being neutralised throughout. (0.05l x 18g = 0.9g HCl) You would expect that the magnesium based compounds would be the most efficient antacids because they have high formula masses that are greater than or close to the amount of HCl being neutralised, in particular MgO which has a formula mass of 0.005 and is neutralising HCl of 0.0225. Apparatus: 50ml burette and stand, burette funnel, glass beaker, pipette, conical flasks, Hydrochloric acid (0.5M), selection of bases (Magnesium hydroxide, Calcium

• Word count: 1416
• Level: GCSE
• Subject: Science

#### Investigation into the energy produced per mole when burning different alcohols to heat up water.

Investigation into the energy produced per mole when burning different alcohols to heat up water. Plan The aim of this investigation is to find out how much energy is produced per mole of alcohol when burning the alcohol to heat up water to a certain temperature rise. Equipment 5 Alcohol Burners: Methanol, Ethanol, Propanol, Butanol, Pentanol, Bunsen Burner, Splints, Wooden Board, Safety Glasses, 200ml beaker, Water, Thermometer, Clamp Stand, Ruler, Scales, Measuring Cylinder, Method Set up all the equipment as shown above. First weigh the alcohol burner, so that the amount of alcohol that has been burnt can be worked out after the experiment has been carried out. Then fill up the beaker with 100mls of water, using the measuring cylinder for greater accuracy. The water used will always be around room temperature, because it is from the tap. Place the alcohol burner on to the wooden board next to the clamp stand, and then attach the beaker with water in, to the clamp stand, directly above the alcohol burner and 15cm from the board, and put the thermometer into the water. Now record the temperature of the water. It should be around 20°C, because that is the normal room temperature. Now light the Bunsen burner. Using the splint, light the first alcohol burner, which is methanol. Let the flame from the alcohol burner, burn until the temperature of the

• Word count: 1011
• Level: GCSE
• Subject: Science

#### To work out the concentration of a substance from the heat energy of neutralisation.

To work out the concentration of a substance from the heat energy of neutralisation. In this test we are going to be putting alkali and acid together,We obviously know that it creates a reaction and when something reacts it creates heat.So I think that the results will be that with an equal amount of acids(25cm3) and alkali(25cm3)there will be the most heat rise.from this we can work out the concentration by the equation N=(hcl)= c x v 000 =2 x V (v will come from the graph) 000 = N x 1000 C By predicting myself now what will happen without using the equation-The biggest reaction will come from the acid and alkali with equal amounts which will produce the most heat Safety: The experiment will include a Bunsen burner which can obviously burn and particularly strong acid and alkali which can burn especially the acis,Alkali can irritate the skin.The first thing to put on should be the goggles as our eyes are then protected before we even come into contact with the acid etc. Bags should be placed under the tables out of anyone's way so no one trips up and all loose clothing to be removed or tied back e.g. Hair.During the experiment These things are going to be/should be in use -A Bunsen burner 5-polysteriene cups(to hold acid and alkali when reacting) 2-heat proof mat 6-Buret 3-tongs 7.goggles(to protect eyes) 4-glass beakers Variables: There are

• Word count: 1268
• Level: GCSE
• Subject: Science

#### Concnetraion Hydorchloric Acid

How does changing the Concentration of Hydrochloric Acid Affect the Rate of Reaction between Hydrochloric Acid and Magnesium? Dependent Variable Volume of Hydrogen Produced - the volume of hydrogen produced in cm3 will be affected by the independent variable which in this case is the concentration of the hydrochloric acid. There is no way in which the volume of hydrogen produced can be controlled however make sure none is lost by making sure that the gas syringe is correctly connected. Measurements will be taken every 30 seconds for the volume of hydrogen produced for 5 minutes. Independent Variable Concentration - the variable which will be controlled is the concentration of the hydrochloric acid. The concentrations which will be used are 2M, 1.8M, 1.6M, 1.4M, 1.2M, 1.0M, 0.8M, 0.6M, 0.4M and 0.2M. The concentrations will be changed by using different measurements of hydrochloric acid and water. Controlled Variable The equation for the reaction can be seen below; Mg(s) + 2HCl(aq) --> MgCl2(aq) + H2(g) I will be controlling many of the variable which affect the volume of hydrogen which is produced. Temperature - The temperature will be controlled because if the temperature was to be changed this could affect the dependent variable. To control this the experiment shall be done in the same lab with no heating and no cooling will be done while the temperature will also

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• Word count: 841
• Level: GCSE
• Subject: Science

#### Halogen element - Production and use

from halogen element Production and use Rock salt deposits are usually mined; occasionally water is pumped down and brine, containing about 25 percent sodium chloride, is brought to the surface. When the brine is evaporated, impurities separate first and can be removed. In warm climates salt is obtained by evaporation of shallow seawater by the sun, to give bay salt. Chlorine is produced on a large scale by any of a number of different methods: . By electrolysis of a concentrated solution of sodium chloride in water. Hydrogen is evolved at the cathode, and chlorine at the anode. At the same time, an alkali metal hydroxide is produced in the electrolyte, and hence this process is often referred to as chlorine-alkali-electrolysis. The chemical reactions that take place at each electrode and the overall cell process are given in the following equations: in which the symbol e- represents a single electron. In the reaction vessel, free chlorine and hydroxide ions must not come in contact with each other, because chlorine would be consumed according to the reaction To accomplish the separation of chlorine gas and the hydroxide ion, a porous wall is inserted between the electrodes (diaphragm process), or the iron cathode is replaced by a cathode consisting of liquid mercury (mercury cathode process) which avoids the production of hydroxide ions at the electrode. Instead, free

• Word count: 1240
• Level: GCSE
• Subject: Science

#### Investigating the factors that affect the rate of reaction between Calcium Carbonate and Acid

Laura Skevington Investigating the factors that affect the rate of reaction between Calcium Carbonate and Acid Aim The aim of my experiment is to see how, and if changing the mass of the Calcium Carbonate affects the rate that Carbon dioxide gas is given off when Hydrochloric Acid is added. Prediction I think that if we increase the mass of the Calcium Carbonate the rate of reaction will speed up. There is greater mass and more surface area so collision between Calcium Carbonate particles and Hydrochloric acid particles is a lot more likely to happen and at a faster rate so more Carbon Dioxide gas will be produced. Scientific Theory behind my prediction - The Collision Theory Picture 1 Picture 2 The Collision Theory can be explained in terms of increasing the number of Collisions between atoms every second. In picture 1 there are 4 atoms of Calcium Carbonate and 10 atoms of hydrochloric acid. The atoms collide with each other and give off Carbon Dioxide gas. The amount of Calcium Carbonate is increased to 8 atoms (Picture 2) and the amount of Hydrochloric acid stays the same. As there are more atoms of Calcium Carbonate so there are more atoms for the Hydrochloric Acid to collide with, this makes collision between atoms more frequent and as a result of this more Carbon Dioxide gas will be given off at the end of my

• Word count: 1310
• Level: GCSE
• Subject: Science

#### Water and Ice- To determine the specific heat capacity of water (a) and the specific latent heat of fusion of water (b).

Physics Full Lab Report (1) Title: (B3) Water and Ice- To determine the specific heat capacity of water (a) and the specific latent heat of fusion of water (b). Date: 25 October 2004 Aim: To determine the specific heat capacity of water through electrical method and to determine the specific latent heat of fusion of water using the method of mixture. In the end, the seriousness of heat loss from the heating curve of water by a heater is to be judged. Experiment (a): To determine the specific heat capacity of water Principle: Specific heat capacity of a substance is defined as E= mc?T, where the energy E depends on the mass m of the object and the temperature change?T. For determination, a calorimeter, which consists of an aluminum calorimeter placed inside an insulating jacket made polystyrene, is used. A certain amount of water is added inside the calorimeter and heated with a heating coil connected to a circuit with power supply. The electrical energy converted to heat can be calculated by E=VIt......(i), where t is the time elapsed during the power supply on. The resulting energy is shared by both the calorimeter and the water. Therefore, we have E=Ew+Ec= mwcw?T+ mccc?T......(ii). Since the specific heat capacity of aluminum is given, determination of that of water can be finally found. Procedure: . The aluminum calorimeter and the aluminum stirrer was taken

• Word count: 1147
• Level: GCSE
• Subject: Science