Heat of Reaction Lab Results and Conclusion
Heat of Reaction Lab Taken from WolframAlpha Time (s) [±0.1s] Temperature (°C) [± 0.000000001°C] Time (s) [±0.1s] Temperature (°C) [± 0.000000001°C] Time (s) [±0.1s] Temperature (°C) [± 0.000000001°C] Time (s) [±0.1s] Temperature (°C) [± 0.000000001°C] Time (s) [±0.1s] Temperature (°C) [± 0.000000001°C] 0.0 25.0552112043 3.5 27.5608658290 27.0 27.9324634075 40.5 29.0494256838 54.0 28.5836678487 0.5 25.3798747085 4.0 27.5840718450 27.5 27.9790974845 41.0 28.8630132258 54.5 28.5604140687 .0 25.6118044200 4.5 27.5840718450 28.0 27.9556847435 41.5 28.8397423740 55.0 28.5371616365 .5 25.8205516882 5.0 27.6072787332 28.5 27.9556847435 42.0 28.7699386776 55.5 28.5604140687 2.0 26.0524731240 5.5 27.6536951709 29.0 28.0023209469 42.5 28.6768873307 56.0 28.6069229881 2.5 26.1685327005 6.0 27.6769047432 29.5 27.9790974845 43.0 28.6069229881 56.5 28.5139105409 3.0 26.3075823036 6.5 27.7001152328 30.0 27.9790974845 43.5 28.6069229881 57.0 28.5836678487 3.5 26.4004768163 7.0 27.7233266511 30.5 28.0023209469 44.0 28.5139105409 57.5 28.6069229881 4.0 26.5395426690 7.5 27.7467292786 31.0 28.0255454854 44.5 28.4906607706 58.0 28.5604140687 4.5 26.6092703221 8.0 27.7699425960 31.5 27.9556847435 45.0 28.5139105409 58.5 28.5836678487 5.0 26.7019928016 8.5
Atomic Structure Notes
Atomic Structure Notes Atoms Atoms are tiny particles which make up matter. They contain a nucleus which is surrounded by electrons. The nucleus itself contains smaller particles called protons and neutrons. The nucleus, and protons and neutrons, are much more massive than electrons. Protons and electrons have a very small electrical charge. Protons are positively charged; electrons are negatively charged. Relative Mass Relative Charge Proton +1 Neutron 0 Electron /1840 -1 Atoms of a certain element all have the same number of protons and electrons, e.g. all atoms of lithium have 3 protons and 3 electrons. Ions Atoms can gain or lose electrons so that they have unequal numbers of protons and electrons. These new particles are called ions. They are indicated by a charge. e.g 27Al3+ this ion has lost 3 electrons. 13 18O2- this ion has gained 2 electrons. 8 Isotopes The number of neutrons can vary. Isotopes are atoms of the same element with different numbers of neutrons and different mass numbers. e.g. chlorine, carbon, hydrogen Isotopes of an element have identical chemical properties, but they can have different physical properties. Isotopes of the same element with more neutrons have: * higher density * higher melting and boiling points * slower rate of diffusion Many isotopes are radioactive; these are called radioisotopes (radioactive
pKa. When constant successive portions of Sodium Hydroxide are added to Acetic Acid; how do the changing amounts of Sodium hydroxide mixed with Acetic Acid in the conical flask affect the pKa of Acetic Acid?
Aspect 1 Research Question: When constant successive portions of Sodium Hydroxide are added to Acetic Acid; how do the changing amounts of Sodium hydroxide mixed with Acetic Acid in the conical flask affect the pKa of Acetic Acid? Background Research: A weak acid is defined as being an acid that does not donate all of its hydrogen ions in a solution (Neuss, 2007) A weak acid represented by HA will always be in equilibrium with its ions in an aqueous solution, for example: HA (aq) - H+(aq) + A-(aq) The equilibrium constant will thus be given as products over reactants by: Ka is most commonly known as the 'acid dissociation constant'. The pKa is just the pH of the Ka i.e. pKa = -logKa and is used as a quantitative measure the strength of a weak acid in solution. Acetic acid (CH3COOH) is a weak acid and Sodium Hydroxide (NaOH), on the other hand, is a strong base and reacts with Acetic acid (CH3COOH) to produce water (H2O) and a salt (NaCH3OO) as follows: CH3COOH + NaOH --> H2O + NaCH3OO A method called a 'Titration' provides information about the behavior of acids through the pH scale. In a titration, base is gradually added until the acid reaches an endpoint or equivalence point. When the equivalence point is reached, the pH of the solution will change rapidly, because all the acid has reacted with the added base. A pH meter can be used to determine the pH of the
alkali titration
Data Collection Table 1. Data collected from the experiment. Table shows three separate trials from the experiment and the Final burette reading, Initial burette reading and Volume delivered from each trial. The average of accurate titration volumes is also included in the table. Titration Rough * Trial 1 Trial 2 Trial 3 Final burette reading (cm3) ±0.075 21.0 20.6 20.4 40.7 Initial burette reading (cm3) ±0.075 0.0 0.0 0.0 20.4 Volume delivered (cm3) ±0.15 21.0 20.6 20.4 20.3 Average of accurate titration volumes : (dm3) ±0.15 20.4 * The Rough was excluded during the calculation of the mean as the rough was a trial to indicate the general whereabouts of the end point, which is inaccurate of the exact end point. Table 2. Observations collected during the experiment. Table contains observations which were recorded during each trial of the experiment. Trials Observations Before trials * When water was added to the crystals of oxalic acid, it dissolved almost instantly with a light stirring of the beaker. Rough * When two drops phenolphthalein was added to the solution of sodium hydroxide, the solution turned pink. * After adding about 20.8dm3 of oxalic acid into the sodium hydroxide solution, while swirling the conical flask, the solution turned completely clear - the oxalic acid was filled up to 21dm3 to have a rounded rough end point
Rates of Reaction Lab
Rate of Reaction Design Experiment Effect of concentration on the rate of reaction between a metal and an acid Introduction In chemistry, chemical kinetics is the study of the factors affecting the rate of a chemical reaction. By definition, rate is the increase in the concentration of one of the products per unit time or decrease in the concentration of one of the reactants per unit time. Many factors trigger the rate of reaction, such as concentration, surface area and temperature. I will investigate the effect of concentration on the rate of reaction between a metal, zinc (Zn), and an acid, hydrochloric acid (HCl). According to the collision theory and based on my experimental results, I will prove my following hypothesis to either be correct or incorrect in theory. Design (D) Aim To investigate the effect of concentration of HCl on the rate of reaction of zinc (Zn)) by measuring the volume of hydrogen produced. Hypothesis As the concentration of the hydrochloric acid (HCl) is increased, the rate of reaction per unit time will increase up to a certain concentration too, until an increase in the concentration of the acid will no longer effect the reaction rate. According to the collision theory, the more concentrated the reactants the more collisions there will be per second per unit volume. As the reactants get used up, their concentration decreases. This
AIM: To verify that mass-mass relationships hold by measuring the amount of NaCl produced.
Ilyas Shaikh IBDP -1 MASS-MASS RELATIONASHIPS AIM: To verify that mass-mass relationships hold by measuring the amount of NaCl produced. HYPOTHESIS: The fundamental law of chemical reactions is the Law of Mass Conservation (or Conservation of Mass). The law states that the total mass of reactants must equal the total mass of products for a chemical reaction. EXPERIMENTAL SETUP AND BACKGROUND: . To perform a reaction using measured samples of reactants 2. To measure the mass of the products; 3. To note the mass - mass relationships for this reaction. APPARATUS REQUIRED: 250 cm3 beaker Bunsen burner Graduated cylinder Safety glasses Spatula MATERIALS REQUIRED: Solid Na2CO3 . M HCl solution PROCEDURE: . I measured the mass of a clean dry 250 cm3 empty beaker to the nearest 0.01 gram. 2. I transferred the Na2CO3 to the beaker using a spatula weighed out 3 grams of it. I measured the mass of the beaker and Na2CO3 to the nearest 0.01 gram and recorded it. 3. I calculated the moles of HCl required to consume the Na2CO3 . 4. I added the acid to my beaker slowly, observing any chemical and physical changes that occur. 5. I heated the beaker on the Bunsen burner to saturate the solution. 6. Next I placed my beaker in the hot air oven to allow excess liquid to evaporate. 7. When the dry
Enthalpy of Combustion of Alcohols Lab
MOLAR ENTHALPY OF COMBUSTION OF ALCOHOLS Lab Asad Ali Tayyab IB HL Chemistry 2 Grade 12 Lab Work Block 8 Mr. Graham MOLAR ENTHALPY OF COMBUSTION OF ALCOHOLS AIM: The purpose of this investigation is to use calorimeter to determine the molar enthalpy change in the combustion of each of a series of alcohols (Methanol, Ethanol and Butan-1-ol) RESEARCH QUESTION: How do the molar enthalpies of combustion change as the alcohol molecules become larger from methanol to ethanol to butan-1-ol? HYPOTHESIS: I think that as the molecules become larger, the enthalpy of combustion will increase. This hypothesis is based on my assumption that as the molecule becomes larger, more bonds are added to a substance. The more the bonds, the harder it is to separate the molecule and the more energy is required to combust the substance. INTRODUCTION: The molar enthalpy of combustion (?H) of a substance is the change of enthalpy, when 1 mole of a substance in its standard state (298 K and 1 atm pressure) is burnt to form products in their standard states. ?Hc may be calculated from standard enthalpies for formation of each of the substances involved in the combustion reaction, or can be estimated from bond enthalpies. Enthalpies of formation are usually obtained directly from combustion experiments. ?Hc is measured in calories. ?H = mC?T IN THIS EXPERIMENT: We will burn
Testing the Suitability of Pool Water. The expected amount of chlorine which is considered safe and could be found in the swimming pool water should be between 3 and 5 mg/dm3
Experiment - Suitability of Pool Water Introduction: Aim: To design an experiment to test the suitability of pool water for usage. Hypothesis: The expected amount of chlorine which is considered safe and could be found in the swimming pool water should be between 3 and 5 mg/dm3 General Background: Chlorine was first discovered in the eighteenth century by Swedish Chemist Carl Scheele, and is today one of the most produced chemicals with a variety of uses. One of its major applications is in the purification and disinfection of water. There are usually millions to billions of microorganisms present in the water and so a disinfectant must be added kill the pathogenic micro-organisms. The disinfectants used for swimming pool water disinfection must meet certain criteria. They should be harmless and non-irritating to swimmers and attendants as well as being active in small concentrations. Chlorine - based disinfectants are among the most frequently used chemicals in the disinfection and maintenance of swimming pool water. They kill bacteria through a fairly simple chemical reaction. The chlorine solution poured into the water breaks down into many different chemicals, including hypochlorous acid (HOCl) and hypochlorite ion (OCl-). Both kill microorganisms and bacteria by attacking the lipids in the cell walls and destroying the enzymes and structures inside the cell,
The chemistry of Alcohols
Lab 11: Investigating the Chemistry of Alcohols )To 2 cm3 of ethanol in a clean dry test tube, drop in a small piece of sodium metal. Repeat with diethylether. Observations for ethanol: * Sodium floats on the surface of ethanol as it reacts * Effervescence( fizzes) seen and the reaction was relatively fast( slower than the reaction of sodium with water). * The reaction is exothermic, and the test tube becomes hot to the touch with time. * Bubbles are also seen as a gas is released. This gas burns with a pop sound when a glowing splint is inserted in the test tube. * A colourless solution is formed which has a similar smell to that of turpentine. Inference: Alcohols are very weak acids( generally weaker than water). As such they react with alkali metals like sodium, but they do not show any other reaction characteristics of acids. If a small piece of sodium is dropped into some ethanol, it reacts steadily to give bubbles of hydrogen gas and leaves a colourless solution of sodium ethoxide, CH3CH2ONa. Sodium ethoxide is known as an alkoxide. If the mixture resulting from the reaction between sodium and ethanol is carefully evaporated to dryness, the white solid product is sodium ethoxide. 2CH3CH2OH(l) + 2Na(s)--> CH3CH2O-Na+(s) +H2(g) Nuclear substitution reactions break the polar C-OH bond of ethanol. The Polar O-H bond is broken when an Ethanol is reduced by
Determination of the % by volume of ethanoic acid in 100cm^3 of water
I.B. CHEMISTRY: PRACTICAL 08-12-12. P2,P3,& P4-STOICHIOMETRY SULAIMAN JALLOH AIM: 1) To prepare a standard solution of potassium hydrogen phthalate by weighing and dissolving it water of correct volume. 2)To use the standard solution of 1) to standardize(find the concentration of) sodium hydroxide solution. 3)To determine the percentage of ethanoic acid,by volume,in vinegar,by titrating with standardized sodium hydroxide in 2) ) MAKING A STANDARD SOLUTION OF POTASSIUM HYDROGEN PHTHALATE RAW DATA TABLE mass of weighing bottle,m+/-0.01g Volume of solution titrated,v+/-0.15 Concentration of sodium hydroxide given ,Cb/mol/ 33.88 250.00 0.1 The purity of the acid is given as 99.5+/-0.5% Calculations for the mass of the acid needed to make 250 of solution of the acid. Equation for the reaction: C6H5COOKCOOH+NaOH C6H5COOKCOONa+H2O so,the mole ratio of the acid to base is 1:1 This means 1 mole of acid gives 1 mole of the base. number of moles of sodium hydroxide,Nb=c v where c=concentration of sodium hydroxide v=volume of solution titrated Nb=0.1 250/1000) Nb=0.0250moles Hence the number of moles of the acid will be 0.0250 moles since the mole ratio is 1:1 number of moles of acid,Na=mass of the acid/molar mass of the acid mass of the acid,Ma=molar mass of the acid number of moles of the acid molar mass of the