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International Baccalaureate: Chemistry
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* Electromagnetic radiation comes in packages called quanta or photons. Atomic Emission Spectra * White light is made up of all the colours of the spectra. * When it passes through a prism a continuous spectrum is obtained. * When energy is applied to specific (individual) elements they emit a spectrum which only contains emissions of particular s. * A line spectrum is not continuous. Each element has its own characteristic line spectrum. * Hydrogen spectrum- it consists of discrete lines that converge towards the high energy end of the spectrum.
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Each half-reaction has a different reduction potential; the difference of two reduction potentials gives the voltage of the cell. Research Question How does the use of different concentrations of copper sulfate solution (half-cell solution) affect the potential difference in a Voltaic Cell? Hypothesis A voltaic cell with a higher concentration of copper sulfate solution will increase the potential difference between the two half-cells. Variables Independent Variable The use of different concentrations for Copper Sulfate solution; 0.2 M, 0.4 M, 0.6 M, 0.8 M, 1.0 M Dependent Variable The change in potential difference (voltage) between the two half-cells of a voltaic cell.
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The molar mass of a compound is the total mass of all of the elements in that compound. The mass of the elements can be found on the Periodic table as atomic mass. Eg molar mass for NaCl = 23 + 35.5 = 58.5g When a substance will not dissolve in water to form an aqueous solution it is said to be insoluble. A precipitation reaction occurs when two aqueous solutions are combined to form a solid in the solution. This solid is called a precipitate. In this experiment known aqueous solution were combined to investigate whether a precipitate could be formed.
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Hesss Law Lab, use Hesss law to find the enthalpy change of combustion of magnesium which is a highly exothermic reaction.
Part 2 I measure out 50 cm3 of 1.00 mol/dm3 of the HCl solution using a graduated cylinder. Then I transferred it into the Styrofoam calorimeter. I weighed off approx. 0.40 g of magnesium oxide using a weighing boat and a scale. I measured the temperature of the of the HCl solution every 30 seconds for 3 minutes. After exactly 3 minutes, I added the magnesium oxide from the weighing boat. I stirred it using the thermometer and read the temperature every 10 seconds for 2 minutes and every 30 seconds for another 3 minutes.
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was the element produced that mainly inflated the balloon, the reaction took place almost immediately. Hence, we have experimented the chemical reaction of a metal acid that produced Sodium Carbonate and inflated a balloon, the reaction was similar to the inflation of an airbag, proving the same chemistry principles. Research Question: How airbags managed to improve automobile safety. Introduction: The development of airbags began with the idea for a system that would save automobile drivers and passengers in a car accident, whether they were wearing their seat belts or not.
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Investigate the rate of reaction of luminol in various factors. The objective was to study the effects of chemiluminescence in several factors: concentration of luminol solution, concentration of hydrogen peroxide and temperature. Rate equation can be fou
Concentration would affect the reaction rate, which can be explained by collision theory(1), increasing the concentration, there are more reactant molecules present in the same volume of solution, and collisions of reactant occur more frequently, therefore the reaction rate increase. Temperature would also affect the reaction rate, as the temperature higher, there is more energy in each reactant molecules, they have faster speed for reaction, and as a result, more collisions occur. This can be explained by the Maxwell-Boltzmann distribution(2).
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Table 1. Uncertainties of Equipments Equipments Uncertainties Burette �0.075ml � �0.08ml, �0.15ml Electronic Balance �0.02g Volumetric Pipette (10ml) �0.020ml Stand N/A Reagent Bottles N/A Table 2. Mixtures and Its Properties Mixtures Properties (�0.15ml) 1 5ml HCl + 5ml ethyl ethanoate 2 5ml HCl + 1ml water + 4ml ethyl ethanoate 3 5ml HCl + 2ml water + 3ml ethyl ethanoate 4 5ml HCl + 3ml water + 2ml ethyl ethanoate 5 5ml HCl + 4ml ethyl ethanoate + 1ml ethanol 6 5ml HCl + 4ml ethyl ethanoate + 1ml ethanoic acid 7 5ml HCl + 1ml ethanoic acid + 4ml ethanol 8 5ml HCl + 2ml ethanoic acid + 3ml ethanol Table 3.
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The mass graphs for the copper anode and cathode in the electrolytic refinement reaction indicate that as xanthan gum concentration increased, the rate of reaction, and subsequently the mass change of the anode and cathode, was reduced. Other factors were gradually eliminated to establish that the viscosity caused a measurable amount of the reduction in reaction rate. The temperature graphs for the sodium ionisation occurring in water indicated that the sodium reached a lower peak temperature when the concentration gradient of xanthan gum within the solution was increased.
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Les �lectrons provenant de cuivre utiliseront l'�lectrolyte (le sulfate de cuivre) pour voyager entre les deux �lectrodes. Si le courant augmente, le nombre d'atomes de cuivre qui seront transf�r�s entre les deux �lectrodes augmentera lui aussi. Donc, la masse de cuivre produite n'a rien � faire sauf d'augmenter elle aussi. Bref, � partir de ceci je peux pr�dire qu'une augmentation du courant va provoquer une augmentation nette de la quantit� de produits, c'est-�-dire la masse de cuivre. 3) VARIABLES a)
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3. We repeated step 2, with water, using 40, 60, 80 and 100 drops. This made the experiment more accurate i.e. gave a more precise mass of the water drop. 4. then, we repeated steps 3 and 4 with the three other liquids - ethanol, glycerine and ethylene glycol. 5. Values were noted down. Further calculations were made using the mole equation - Number of moles = And, also using Avogadro's constant, where the number of molecules in one mole of a substance is 6.023 � 10��. Controlling, varying and monitoring the variables - > The independent variable was varied by using not one, but four different types of liquid.
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CONCLUSI�N..........................................................................21 7. BIBLIOGRAF�A.........................................................................24 La espuma es un producto muy com�n, al cual se le han dado usos caseros e industriales. Esta espuma es obtenida a trav�s de derivados del petr�leo, lo cual resulta ser muy t�xico para el medio ambiente. Con esta monograf�a, mostrar� los beneficios ecol�gicos que trae reemplazar el uso del petr�leo en la fabricaci�n de la espuma, por un producto totalmente biodegradable. Antes de empezar a hablar acerca de la producci�n de espuma y el reemplazo del petr�leo en su fabricaci�n por un compuesto biodegradable, voy a aclarar algunos conceptos que son necesarios para entender el trabajo que les voy a mostrar a continuaci�n.
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It was given to pregnant women to treat morning sickness, but it cause deformities in babies! Now it is still used, but to treat skin sores. B.1.3. Describe the different methods of administering drugs * Oral: Very convenient. However, it might not be reliable as the rate of absorption depends on drug concentration, stomach content and pH value. As most is absorbed in the small intestines, so the drug must survive the gastric acid. Therefore it often lays in time release capsules. * Rectal: Good when drug cannot be taken orally due to vomiting or because the drug is pH sensitive.
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The equation for the reaction between sodium bicarbonate and Hydrochloric acid is as follows: Na2CO3(s) + 2HCl(aq)--> 2NaCl(s) + H2O(l) + CO2(g) Even though each mole of Sodium bicarbonate will neutralize 2 moles of hydrochloric acid as seen from the mole ratio in the above reaction, I predict that the citric acid will act against neutralization. This in my view, will make the Eno powder very ineffective. On the other hand, Actal Tums contain Calcium carbonate powder. Although we are not notified about the percentage composition of calcium carbonate powder in the tablets, there are no other ingredients mentioned which work against the action of the antacid.
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In this experiment the specific heat for a unknown metal will be calculated. This specific heat will then be compared to the true value which suggests how accurate the calorimeter is. Likewise, in order to find the amount of heat released by a chemical reaction that leads to neutralization, solutions of each the acid and the base are formed that have an equal molarity. These two are then mixed inside the calorimeter and stirred for two minutes and then the temperature of the solution taken. All the necessary data is collected and then the heat of neutralization is obtained.
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According to the IAEA (International Atomic Energy Agency), the average electricity consumption per capita was 4010kWh in 2002. As the figure "per capita" applies to only the consumption of one person, I must multiply this figure by the number of people living in my house in order to compare it to the amount my family consumes. During the time of this electricity bill, four people lived in my house: 4010 x 4 = 16, 040 kWh / per year From the calculations and graph above, we can see that a Portuguese family of four will consume, on average, 16040kWh of electricity.
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Biodiesel Investigation - How the concentration of Potassium Hydroxide solution would affect the yield of biodiesel when transesterified with a standard sample of vegetable oil .
I do feel as though this is an important experiment to engage in as scientists find biodiesels an extremely useful substance to use in machines and such. To try an experiment which involves looking at factors that can change the output of the product, would be a stepping stone to building a stronger understanding on the substance itself and how more of it can be obtained and perhaps what benefits it may serve. The experiment conducted was intent on looking at a certain independent variable (the concentration)
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Volume of substance Z solution ? 25.0cm3 of substance Z solution was used for each of the nine trial. Dependent Variables: 1. Volume of 0.1M HCl required to neutralize 25.0cm3 of substance Z ? The end-point was determined only when the methyl orange indicator completely changed color from yellow to orange. Controlled Variables: 1. Molarity of HCl ? It was 0.1M for all trials. 2. Drops of Phenolphthalein ? For all trials, only three drops were used to prevent any misinterpretation of the reaction?s end point. 3. Volume of water used to dissolve all samples of substance Z ? For all trials, only 250cm3 of distilled water was used.
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This is because he stated that according to the law of conservation of energy, the total enthalpy change of a reaction will depend only on the difference between the enthalpy of the product and the enthalpy of the reactants and not on what path it follows. This is known as Hess?s law. The alternate set of stepwise reactions that were followed in this experiment to arrive at the value for the enthalpy of formation of MgO(s) are as follows: 1.
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infers that the rate of reaction is impacted by how often molecules collide with one another. This can be applied to my hypothesis to suggest that with the occurrence of more collisions in the reaction- due to a higher percentage of particles in the more concentrated H2SO4 solutions- it will result in the formation of more bonds and hence, lead to a quicker rate of reaction between two reactants, leading to a quicker production of 20mL of H2 gas. Macintosh HD:Users:160161:Desktop:Screen Shot 2015-03-22 at 2.41.05 pm.png VARIABLES The independent variable (the variable being changed): The independent variable is going to be the varying concentration- measured in molarity mass (M)- of Sulfuric acid (H2SO4)
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3. 4. Now, we can use q=mc ?T to calculate the energy gained by the solution: 1. 2. 3. Therefore: 1. Now, we have to calculate the number of moles for MgO: 1. 2. 3. We can now calculate the change in enthalpy by dividing the q of the reaction by the moles of the limiting reagent: 1. Now, we do reaction 2, trial 1 so we can use Hess?s law to calculate the change in enthalpy of formation, but first we are going to calculate the uncertainty in this expression: First, we calculate the uncertainty for the: 1.
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However, when the base is added and the endpoint has been reached, the color changes to yellow. If over titration occurs, the solution will still remain yellow. 16.90 17.20 0.3 17.20 17.40 0.2 17.40 17.60 0.2 17.60 17.80 0.2 Methyl Red 0.00 5.00 5.0 The indicator is red-pink at first when added to the acetic acid. However, when the base is added and the endpoint has been reached, the color changes to a light orange shade. If over titration occurs, the solution will change yellow. 5.00 7.80 2.8 7.80 10.70 2.9 10.70 13.60 2.9 13.60 16.50 2.9 Bromocresol Green 20.80 21.20 0.4 The indicator is yellow-green at first when added to the acetic acid.
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Measuring the fatty acid percentage of the reused sunflower oil after numerous times of potato frying and determining the effects of it on human health.
are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid. As they do not exist naturally, trans-fats are difficult to metabolize and so they accumulate in the fatty tissues of the body. They also cause an increase in the levels of LDL (bad) cholesterol and a decrease in the levels of HDL (good) cholesterol, which can lead to atherosclerosis (narrowing of the arteries) and a resultant increase in the probability of strokes and heart problems. LDL is low-density lipoprotein; HDL is high- density lipoprotein. Their density is determined by the amount of proteins present in the molecule.
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radiation from the sun breaks the bonds of molecules to form atoms and free radicals. Temperature in the ionosphere is about -50ºC. Point 4.2 – Identify the main pollutants found in the lower atmosphere and their sources. Here is a table showing the main pollutants found in lower atmosphere (troposphere) and their sources: Pollutant Sources – artificial (caused by humans) Sources – natural Nitrogen oxides (NOx) e.g. nitrogen dioxide, nitric oxide The high temperature environment in internal combustion in vehicles. N2 (g) + O2 (g) ï 2NO (g) Burning of biomass, heat caused by lightning, soil bacteria. Carbon monoxide Incomplete combustion in motor vehicles C8H18 (l) + 5O2 (g) ï CO( g) + 7C (s)
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Research question: how to convert NaOH to NaCl by two different routes , and measure the enthalpy changes for each one in order to test Hesss law ?
ΔT = the change in temperature (ºC) Given the volume and concentration of each solution, the number of moles for each substance in the reaction can be calculated, therefore, the enthalpy of each reaction can be calculated in materials needed : 1. ( 8.0 grams )sodium hydroxide, NaOH 2. labQuest 3. 2 graduated cylinders of size( 100 mL ± 0.5) 4. (100 cm3) 2 M Hydrochloric acid solution ,HCL 5. Measuring pipette (25cm3) 6. glass stir stick 7. mortar 8.
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The aim of this experiment is to examine the enthalpy of combustion of the first five alcohols and to see how does it change with the increasing chain length
Hypothesis : The longer the chain , the higher the heat of combustion . Explanation of the expectations : The more bonds there are holding the carbon, oxygen and hydrogen atoms together, more energy will be required to break them apart. For example Ethanol has the formula C2H5 OH. In this formula there are five C-H bonds, one C-C bond, one C-O bond and one O-H bond. To separate these types of bonds certain amount of energy is required , which will be shown later.
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