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International Baccalaureate: Chemistry
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For this experiment, the conversion of NaOH to NaCl by two different routes was used and the change in enthalpy for each path was measured to test Hess's law. Route one: - NaOH + 2M HCl 2M NaCl 2M NaCl + H2O 1M NaCl Route two: - NaOH + H2O 2M NaCl 2M NaOH + 2M HCl 1M NaCl Materials: - beakers, NaOH, 2M HCl, stopwatch, thermometer, pipettes, measuring cylinder Methods: - for the first route, 4g of NaOH was weighed.
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The burette was attached to the stand with the help of a clamp. 2. The burette was then closed and 50 ml of NaOH was poured in. 3. 25 ml of weak acid was poured into a beaker with the help of a voll pipette and a magnet was dropped inside. 4. The beaker was then placed on the magnetic stirrer and the stirrer was turned on. 5. The pH meter was calibrated using buffer solutions of pH = 4, and pH = 7.
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0.5M Volume Temperature Table 3-Increase in Pressure over Time as 0.44M and 0.5M react at 22.5 Time (s) Pressure (kPa)�0.2% 10 101.3 20 101.6 30 101.8 40 102.0 50 102.7 60 103.1 70 103.6 80 104.3 90 105.2 100 106.1 110 107.0 120 107.9 130 108.8 140 109.7 150 110.6 160 111.8 170 112.7 180 114.0 Part 4 Element Molarity 0.88 M (3%) 0.5M Volume Temperature Table 4-Increase in Pressure over Time as 0.88M and 0.5M react at 30.0 Time (s)
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Explain the differences in the boiling points between similar massed short chain(>5 C) alcohols and alkanes. 6) What is the functional group in an aldehyde? An aldehyde consists of a terminal carbonyl group, O=CH 7) Explain the differences in the boiling points between methanal and methanol? Since, methanol is an aldehyde; it has a terminal carbonyl group, resulting in only dipole-dipole forced holding two molecules together. On the other hand, methanol contains a hydroxyl group (since it's an alcohol), resulting in hydrogen bonding also holding two molecules together.
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In term of melting points of alkanes, the basis of the classification is the alkane's ability to pack with corresponding alkanes. The better the pack between the alkanes (the more solid the two molecules), the higher the melting point, as the more rigid and fixed the structure, the harder it is to melt it. Generally, even numbered carbon alkane chains have a higher melting point (within its range) as they pack into more organized solids which require more energy to melt, than odd-numbered carbon chains.
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t = time (seconds) M = molar mass of copper (63.55) n = number of moles of electrons (2; copper ion has a 2+ charge) w = mass of plated copper (grams) Variables: Type of Variable Variable Ensured? Dependent Variable * Mass of deposited copper on cathode * Weighed using a 3 d.p. balance Independent Variable (quantitative) * Time Taken * Timed using stop clock Controlled Variables * Temperature * Water bath was used * Thermometer placed in water bath (26oC) * Volume of Copper (II) Sulphate * A burette was used to measure volume * Concentration of Copper (II)
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balance * Surface Area of Magnesium * Used powder & made sure mass was the same * Volume of Hydrochloric Acid * A burette was used to measure volume Requirements: * water bath (30oC) * 500cm3 conical flask * rubber stopper * delivery tubing * measuring cylinder * clamp stand * stop clock * 0.06g magnesium powder * 20cm3 hydrochloric acid * 3 d.p. balance * spatula * weighing boat * burette (x2) * thermometer in water trough * safety goggles Apparatus: Technical Notes 1)
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I decided to draw my graph landscape as I figured out that drawing the graph landscape is the best method to draw the conclusion and working out the temperature rise as the data are more spread out so I can draw out a more accurate measurement. After working out the change in temperature from the graph, I will then use the value to calculate the heat given out (in Joules) during the experiment. The equation that I will be using is: q = mc ?T Hence, q = 4.18 x 28.1 x 50.0 = 5872.9 J Moles of aq copper
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Aim: To determine the concentration of chloride ions in sea water by titration with silver nitrate solution of known concentration.
Filter funnel 6) (10.00�0.05)cm3 pipette 7) (25.00�0.06)cm3 pipette 8) Pipette filler 9) (250.0�0.1)cm3 volumetric flask 10) Safety glasses 11) Distilled water 12) Paper towels Chemicals: 1) Approximately 50 cm3 of F1 (0.05 moldm-3 silver nitrate solution) 2) Approximately 30 cm3 of sea water 3) Indicator: 2 moldm-3 potassium chromate solution Variables: 1) Independent variable: - 2) Dependent variable: Volume of AgNO3 used. 3) Controlled variables: Variable Reason How it will be controlled Volume and concentration of seawater used. If different volumes and/or concentrations are used, the average cannot be taken to reduce random error. Dilute sufficient seawater for all readings taken.
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The purpose of this experiment is to find the composition of a sample of sodium carbonate mixture by titration.
A standard solution is prepared. 3. Burette is rinsed with HCL and then filled with the acid. The tip is also be rinsed. 4. The initial burette reading is recorded in the 'Trial column' 5. 25 cm3of the sodium carbonate solution is absorbed by the pipette and the pipette is rinsed by the sample solution. 6. 25 cm3 of the sodium carbonate solution is transferred to a conical flask 7. Water is added to the volumetric flask until it reach to the graduation mark 8. 2-3 drops of phenolphthalein indicator solution is added 9. Hydrochloric acid is run from the burette into the volumetric flask until the solution turn from pink to colourless 10.
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Ions important to human health - Iron is one of the most important ions in the maintaining of homeostasis in the human body.
In the first few months of life, infants will use up most of their iron stores; a diet of formula may not have enough iron to replenish those stores. It is therefore important to add iron-containing foods to an infant's diet by the age of 6 months. There are two main types of dietary iron. About 90% of iron from food is in the form of iron salt and is called nonheme iron, which is poorly absorbed. The other 10% of dietary iron is called heme iron, which is found in the hemoglobin & myoglobin of meat and is well absorbed.
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What effect does the change in temperature have on the reaction rate of the reaction between sodium thiosulphate and hydrochloric acid?
The rate of reaction, k, is defined as 1/time. These values as well as the ln (k) and 1/Temperature (1/T) are shown below. k ln(k) 1/T 0.0018 -6.3 0.0033 0.0037 -5.6 0.0032 0.0044 -5.4 0.0031 0.0086 -4.8 0.0030 0.0108 -4.5 0.0029 A graph of rate of reaction vs. temperature is shown below. This graph shows that the reaction order is 2. However, to produce the negative gradient needed for calculations the inverse of temperature must be used instead of the temperature, this is shown below. However, this does not provide the activation energy or the Arrhenius Constant of the reaction.
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Add one of the pieces into the solution and start the stop watch the second you drop the piece in. Observe, and stop the watch when the piece completely dissolves. Record the time in the data table. 8. Clean the beaker and repeat step 6 & 7 for two more trials. Then clean all used glass wear. 9. Now obtain 35 mL of 12 M hydrochloric acid. 10. Acquire 385 mL of water and pour into the 450 mL beaker and add the acid into it and stir.
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Examples of his calculations found were as follows: percent uncertainties, percent error, and calculations of specific heat mass (etc). (Of course with more detailing). The specific heat formula is q = mc?t. Sample Calculations Trial 1: Converting density of H2O to g H2O 1 g H2O ? 100 mL = 100 + .5 % g H2O The density of water, given in class during the duration of the experiment, is 1 gram per milliliter. So that was taken and multiplied times the 100 mL of water used in the experiment.
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Determining the Concentration of Calcium Carbonate in an Unknown Substance through the Methods of Titration Aim:
Using the distilled water on the sides of the flask was rinsed down to bring the sodium hydroxide to the rest of the solution in the flask. Also, when dropping a half-drop into the flask, the following procedure was used: First, a half-drop was made at the tip of the burette. Then, using the flask, the half-drop was collected to the flask's side. Finally, using the distilled water, the half-drop was rinsed down to the rest of the solution. To make it easier to recognize the endpoint of the reaction, a white paper was put under the flask.
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Dependent Variable: The volume needed to titrate the calcium carbonate solution by using the phenolphthalein indicator. Though it is a clear substance, the indicator will change its color into pink when the solution becomes a base from an acid. By determining the amount of hydrochloric acid is needed to change the color of the solution, we can determine the concentration of calcium carbonate through some calculations. Controlled Variables: 1. The Distilled Water: The distilled water will be the only water that will be used during the entire experiment.
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Buffers. This experiment lets us to know more about the buffer solutions and how the pH changes by adding acid and base to the buffers.
Also two kinds of buffer solutions can be used to make a compare. 1. Get 7 beakers. 2. Label each of them. 3. Make a buffer solution contains Na2CO3 and NaHCO3. 4. Put the buffer solution equally into two beakers. 5. Make another buffer solution contains Na2HPO4 and NaH2PO4. 6. Put the buffer solution equally into another two beakers. 7. Get NaHCO3, NaHPO4 and water separately into the rest three beakers. 8. Use the pH paper to measure the approximate pH value.
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Gas laws, investigate quantitatively the relationship between the pressure and volume for nitrogen gas.
will double. Thus for a fixed mass of gas at a constant temperature, the pressure should be inversely proportional to the volume of the container. Variables: Independent Variable (variable to be manipulated); volume of the nitrogen gas Dependent Variable; the pressure of the gas Controlled Variables; the type of gas, mass (or amount) of the gas, temperature of gas Planning b Apparatus and Materials: A pressure gauge, the type used to measure tire pressure (a mechanical pressure gauge) was used.
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Our aim is to design a practical investigating how that effect alters the speed of the reaction in a chemical reaction between magnesium and hydrochloric acid.
area of the magnesium was determined simply by cutting a piece of magnesium ribbon of 4cm and cutting this ribbon into small particles and then that surface area was changed by taking another piece of ribbon with the same length 4cm but cut into smaller particles. Five types of surface areas were used and in each time the mass was taken to make sure they all have the same mass. According to the dependent variable which is the rate of the reaction, it was measured using a stopwatch that starts whenever the magnesium is dropped in the hydrochloric acid solution, and stops when the reaction is complete.
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Chemistry Lab Report. AIM: To calculate the number of molecules of water of crystallization in hydrated copper sulphate.
- Repeat the procedure approximately five times to get the desired level of accuracy. SAFE TEST: The following precautions must be taken to prevent accidents from taking place. - Safety glasses must be worn at all times during the experiment. - The apparatus must be handled with care in order to prevent breakages. - While lighting the Bunsen burner one must be cautious while adjusting the air hole, the gas tap and lighting the burner. - Always use tongs while lifting the lid of the dish.
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However, recent studies have shown that Teflon may be toxic or is even likely to cause cancer. This essay will discuss the uses of Teflon, and the myths and truths surrounding it. CHEMISTRY: Polytetrafluoroethylene is a long chain of tetrafluroethylene monomers bonded to each other. It is a carbon chain backbone with two fluorine atoms attached to it. In a monomer tetrafluroethylene unit, a carbon is double bonded to another carbon, and then bonded to two fluorine atoms as show in the diagram below. In order for these monomer units to become polytetrafluoroethylene or PTFE, they must undergo polymerisation in which the carbon to carbon double bond is broken to form a chain.
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[Temperature of the lab] The temperature of the lab was kept at a constant 25�C, which maintained the density of the water so the surface tension would not change. [Volume of the penny] This value will be determined in the experiment using a displacement measurement that will be elaborated on in the procedure. Procedure 1. Fill a beaker and use a ruler to ensure that the water level extends 1mm above the brim of a beaker, which makes it so the water has to rely on surface tension to ensure it does not spill.
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soluble (dark orange brown) yes (purple) no no 72� Glucose C6H12Cl white powder yes no no no no >120� Table 2: Theoretical Result Sample Appearance Solubility Conductivity Melting point Water Propanol Hexane Solid Aqueous Aluminum Al shiny grey powder no no no yes no 660.37 �C Graphite C grey powder no no no yes no 3675 �C Sucrose C12H22O11 white powder yes yes yes no no 186 �C Zinc Zn silvery solid no no no yes insoluble 419.58 � C Iron Fe brown solid/powder no no no yes insoluble 1535 � C Sodium Chloride NaCl white crystals yes no no
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Basic Basic Amphoteric Structure of oxide (simple molecular, giant molecular, giant ionic) Giant ionic lattice giant ionic lattice Ionic/covalent Data Table 2: Properties of the chlorides in period 3 Element Na Mg Al Si P Formula of chloride NaCl MgCl2 ACl3 SiCl4 PCl5 Appearance and state of chloride Colorless/white crystalline solid white crystalline solid pale yellow solid Colourless Liquid Colourless liquid Volatility of chloride low low low High high Action of water on chloride It dissolves in the water It dissolves in the water A slightly violent reaction takes place, hydrogen chloride gas is produced Very rigorous reaction, HCl fumes evolved.
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Energy is absorbed when bonds are broken and energy is released when they are formed (Newton, 2008, pg1). Energy change cannot be directly measured. However energy change affects the physical force of heat. Therefore a heat change is indicative of an energy change. If the heat increase in the solution the change will be exothermic and if the heat decreases the reaction will be endothermic. In respects to the formula Magnesium forms an ionic bond with chlorine to form the salt magnesium chloride.
- Word count: 1400