Handling Experiments,Observations and Data
Handling Experimental observations and data. Title: The no. of moles of water crystallization in a hydrated salt, Aim: To determine the water of crystallization in the hydrated salt, copper sulphate. Apparatus: electronic balance, crucible, tongs, Bunsen burner, wire gauze, tripod stand, pipe - clay triangle, spatula, . Theory: To determine the number of moles of water of crystallization in a hydrated salt, a small amount of the hydrated salt is taken, heated gently and then heated strongly to remove the water of crystallization. Procedure: . Take a clean and dry beaker and weigh it out accurately in an electronic balance. 2. Weigh out accurately 2.5 g of hydrated copper sulphate crystals in the crucible. 3. Heat the contents of the crucible gently at first and then strongly. 4. Remove the crucible from the burner when all the water of crystallization is removed from the copper sulphate crystals. 5. Allow the contents of the crucible to cool down. 6. Weigh out the crucible with its contents again until a constant reading is obtained. Table of Results Substance to be Weighed Weight in Grams Beaker alone 50.00g Beaker + copper sulphate before heating 52.50g Beaker + copper sulphate after heating 51.44g Observation: * The beaker was not directly over the fire and the blue copper sulphate crystals at the bottom of the beaker begin to turn white. * In the
Investigating The Rate Of Reaction Between Sodium Thiosulphate And Hydrochloric Acid
Investigating The Rate Of Reaction Between Sodium Thiosulphate And Hydrochloric Acid In this coursework I am going to be investigating the rate of reaction between sodium thiosulphate and hydrochloric acid. The rate of reaction can be changed by theses 4 factors: . Temperature 2. Concentration 3. Catalyst 4. Surface area For this course work I have decided to find out how concentration affects the rate of reaction between Sodium Thiosulphate and Hydrochloric Acid. The equation for this reaction is: Sodium Thiosulphate + Hydrochloric Acid Sodium Chloride + Sulphur + Sulphur Dioxide + Water Na2S203(aq) + 2HCL (aq) 2NaCl(aq) + S(s) + SO2(g) + H2O(l) When Sodium Thiosulphate and Hydrochloric Acid are mixed together, the solution turns from a colourless solution to a cloudy colour gradually change again into a yellow colour solution (This is called Sulphur). Because the solution turns from a colourless liquid to a cloudy colour solution we could use this information to show how concentration affects the rate of reaction. This experiment I am going to carry out is both simple and safe. I will be carrying out this experiment in the school laboratory because of the space and the equipment I will need is widely available. In order for my experiment to be fair I will make sure that the measuring cylinders for the Hydrochloric Acid and Thiosulphate will not be mixed up,
To determine the concentration of a limewater solution
To determine the concentration of a limewater solution Aim: I am going to determine the concentration of lime water through titration. In this investigation I will use 2.00 mol dm?³ hydrochloric acid and 1gdm?³ of calcium hydroxide. But as the acid has a higher concentration I shall need to dilute it. I will also work out the number of moles in calcium hydroxide [Ca(OH)2] so that can identify the amount needed of hydrochloric acid. I will first need to dilute the hydrochloric acid and then next thing is to decide on the indicator which I will be using in this experiment. The indicator will be used to make the solution become neutral when the base has been reacted fully. The indicator which I will be using is phenolphthalein. The first thing to do is calculate the moles of calcium hydroxide. This has been done below: Hydrochloric acid = 2.00 mol dm?³ Calcium hydroxide [Ca(OH)2] = 1gdm?³ Therefore the moles equals mass divide by the relative molecular mass. Moles = Mass RMM Calcium = 40 Oxygen = 16 Hydrogen =1 = 1 = 1 40+(16×2)+(1×2) 74 = 0.0135 moles of calcium hydroxide The formula which the calcium hydroxide will react with the hydrochloric acid is: Ca(OH)2(aq) + HCL CaCl2(aq) + H2O(l) When balanced= Ca(OH)2(aq) + 2HCL
To investigate the effect of temperature on the rate of reaction
GCSE Triple Science Chemistry: Rate of Reaction Aim: To investigate the effect of temperature on the rate of reaction Define: Chemical Reaction A chemical reaction is a process that results in the interconversion of chemical substances. The substance or substances initially involved in a chemical reaction are called reactants. Chemical reactions are characterised by a chemical change, and they yield one or more products which are, in general, different from the reactants. Classically, chemical reactions encompass changes that strictly involve the motion of electrons in the forming and breaking of chemical bonds, although the general concept of a chemical reaction, in particular the notion of a chemical equation, is applicable to transformations of elementary particles, as well as nuclear reactions. [Source: Wikipedia] Collision Theory - Energy of the Collision Activation Energy Regardless of whether the species are orientated correctly, a reaction will still not fail to occur unless the particles collide with a certain minimum energy called the activation energy of the reaction. Activation energy is the minimum energy required before a reaction can occur. This can be shown on an energy profile for the reaction. For a simple over-all exothermic reaction, the energy profile looks like this: If the particles collide with less energy than the activation energy, nothing
Investigating The Energy Change During A Neutralisation Reaction.
Investigating The Energy Change During A Neutralisation Reaction INTRODUCTION: How the change in temperature affects the amount of energy taken in, or given out during a neutralisation reaction? AIM: I am going to investigate the change in temperature, which happens during the process of neutralisation. The acid I will use is Hydrochloric Acid and my alkali will be Sodium Hydroxide. Acids and Alkali's react together to form neutral substances, this is a process, which is known as neutralisation. A neutralisation reaction takes place when an acid and an alkali react with each other to form salt and water. The strength or weakness of an acid or alkali is measured on a pH scale. A strong acid will be on a pH of 1.5, however, a strong alkali will have a pH of 14, and the pH value of 7 would be neutral. Acids are soluble in water, the react with carbonates to give salt, carbon dioxide and water. Acid solutions also conduct electricity but are decomposed by it, which shows that the acids consist of ions, which suggests that all acids contain H+ ions. FACTORS THAT AFFECT THE ENERGY CHANGE / VARIABLES: > TEMPERATURE > Concentration of Sodium Hydroxide > Concentration of Hydrochloric Acid > The Volume of Acid and Alkali INDEPENDANT VARIABLE: The factor I will change during the experiment will be the amount of Hydrochloric acid. I intend to use five different
Chem MC analysis. In which of the following cases may it obtain a complete neutralization? (1)25.0 cm3 of 0.120 M sulphuric acid and 50cm3of 0.120M sodium hydroxide solution (2)50.cm3 of 0.5 M Sodium hydroxide and 0.025 moles of aqueous ammonium chlorid
Chemistry 4A Ivan Liu Chun Pok (12) Non-practical task Mc analysis Topics: Neutralization, Reaction between alkali and ammonium compound, Strength of Acid and Alkali, Reacting Masses, Volumetric Analysis In which of the following cases may it obtain a complete neutralization? (1)25.0 cm3 of 0.120 M sulphuric acid and 50cm3of 0.120M sodium hydroxide solution (2)50.cm3 of 0.5 M Sodium hydroxide and 0.025 moles of aqueous ammonium chloride (3)20.0cm3 of 0.100M phosphoric acid and 30.0cm3 of 0.200 M potassium hydroxide solution (4)Dissolve 0.2025g of solid sodium hydroxide in water and make up to 250cm3 of solution, then 25.0cm3 of this solution is added to 50.0cm3 of 1M hydrochloric acid A.2 B.1, 3 C.3, 4 D.1, 2, 4 Option 1: H2SO4(aq) + 2NaOH(aq)--> Na2SO4(aq) +H2O(l) Mole ratio of H2SO4 : NaOH = 1:2 ?Using the formula, Molarity of a solution M or mol dm-3 = Number of moles of solute (mol) / Volume of solution (dm3) ?Number of moles of solute (mol) = Molarity of a solution M or mol dm-3X Volume of solution (dm3) Number of moles of H2SO4 given: 0.12 X (25.0 /1000) = 0.003mol Number of moles of NaOH given: 0.12 X (50.0/1000) = 0.006mol Mole ratio of H2SO4 : NaOH = 0.003 /0.006 = 1:2 Therefore, option (1) is correct. Option 2 : NaOH(aq) + NH4Cl (aq)--> NaCl(aq)+ NH3(g) + H2O(l) Mole ratio of NaOH : NH4Cl
Anti-acids
Rates of Reaction in Antacids Aim I plan to investigate the effectiveness of indigestion tablet on HCl. I will take five different tablets containing a specific pH of alkali and discover how long it takes for the indigestion tablet to neutralise the acid. The test will tell me which is the fastest acting tablet is in the case of indigestion. Antacids Antacids are bases and most of them react on the excess build up of stomach acid and neutralises the acid. The most common of these bases are hydroxides, carbonates or bio carbonates. Neutralisation If you have a weak acid you can eliminate the acidic pH by combining it with a weak alkali. Neutralisation is a chemical reaction which is caused by combining both an acid and an alkali, this reaction causes both the solutions to cancel each other out, and this reaction leaves you with water and salt. Neutralisation is simply the combination of hydroxide ions OH and hydrogen ions H+ this process leaves you with the molecule H2O and forms salt. A Catalyst Catalyst are use to speed up a reaction without being used up. In some reaction like digestion catalyst are essentially needed to speed the process or digestion would take too long to gain nutrients. A catalyst breaks down a substance to provide a larger surface area to speed up the process. The Rate of Reaction The amount of time the reaction occurs. Magnesium +
The Effect of pH on the Strength of Keratin (hair protein).
Science Plan The Effect of pH on the Strength of Keratin (hair protein) Relevant Information: Keratin is a fibrous protein and has a structural function. Fibrous proteins contain polypeptides that bind together to form very long fibres running parallel to each other. These fibres are linked by cross-bridges that make the protein strong and insoluble. The main constituent of hair is the protein keratin. Keratin can also be found in horns, nails, claws and feathers. These examples suggest keratin has a strong structure. Like most other proteins it is made of monomers called amino acids. All Amino acids contain both an acidic carboxylic group (-COOH) and a basic amino group (-NH2); there is also an R group that changes with each different amino acid. They all consist of carbon, hydrogen, oxygen and nitrogen atoms. Keratin also contains a high concentration of the amino acid cysteine; this contains a sulphur atom. The sulphur atoms from two cysteines join together, forming a very strong disulphide bond. These bonds are covalent and form strong links making the tertiary structure of the protein very stable. The disulphide bonds occur down the length of the keratin fibre and the cross-linking between the keratin chains account for the strength of hair. Within each hair strand the keratin chains are also linked with ionic, salt and hydrogen bonding. Hydrogen bonding occurs from
Types of Chemical Reactions
7 February 2009 Types of Chemical Reactions Introduction The purpose of this experiment is to become familiar with chemical reactions, and the numerous different types of chemical reactions. According to the textbook, a chemical reaction is defined as a chemical change -a rearrangement of the ways in which the atoms are grouped. We know that a chemical reaction has taken place when something changes. For example, when steel changes from a smooth, shiny material to a reddish-brown, flaky substance known as rust, a chemical reaction has occurred. These reactions often show visual change, but are not always visible in some cases. There are many different types of chemical reactions: synthesis, decomposition, single displacement, double displacement, combustion, oxidation-reduction, and acid-base reactions. In this experiment, we learn about synthesis, decomposition, single displacement, and double displacement reactions. Synthesis, or sometimes called combination reactions, happens when a given compound is formed from simpler materials. In many cases, synthesis reactions start with pure elements. Oppositely, a decomposition reaction occurs when a compound breaks down into simpler compounds. A displacement reaction involves the exchange of anions, and can be single displacement -which exchanges only one set of anions- or double displacement, in which both associations are
equilibrium constant
Experiment 13 Aim: To determine the equilibrium constant for esterification from ethanoic acid and propan-1-ol. Procedure: . 0.25 mole (equals to 14.3 cm3) of glacial ethanoic acid (density = 1.05 g cm-3) and 0.25 mole (equals to 18.8 cm3) of propan-1-ol (density = 0.8 g cm-3) was put into a clean, dry pear-shaped flask. It was mixed thoroughly. 2. 1.0 cm3 of the mixture was transferred by pipette to a 250 cm3 conical flask containing about 25cm3 deionized water and 2 drops of phenolphthalein indicator. It was titrated to end point with 0.50 M sodium hydroxide solution. The titre (V1 cm3)was recorded. 3. 8 drops of concentrated sulphuric(VI) acid was added to the remainder of the acid-alcohol solutions while continuously swirling the flask. Another 1.0 cm3 sample was titrated immediately. The titre (V2 cm3)was recorded. The difference between V1 and V2 Represents the volume to be subtracted from subsequent titration to correct for the amount of sulphuric (VI) acid present. 4. A few anti-bumping granules were added to the flask, and it was attached to a water-cooled reflux condenser. It was refluxed for 1 hour. The flask and its contents in an ice bath was cooled. 1.0 cm3 sample was removed from the flask for titration with the 0.50 M sodium hydroxide solution as before. The titre needed was recorded (V3)and was corrected for the sulphuric(VI) acid. 5. Refluxing was
