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Essay about entropy of thermodynamic
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ENTHALPY What is enthalpy? Enthalpy is the amount of heat content used or released in a system at persistent pressure. Enthalpy is typically articulated as the change in enthalpy. The change in enthalpy is linked to a change in internal energy (U) and a change in the volume (V), which is multiplied by the constant pressure of the system. 23/04/14 (http://chemwiki.ucdavis.edu/Physical_Chemistry/Thermodynamics/State_Functions/Enthalpy) When the reaction is giving off heat, it is exothermic. In this case, the enthalpy change is negative, since the reaction is going from high energy to low energy due to the loss of heat energy to its surroundings. If energy flows from the surrounding environment and heat is being taken in, it is endothermic. The change is positive as the system is gaining energy in the form of heat. Bond Making and Bond Enthalpy Bond enthalpy is the energy that is required to break a chemical bond. In most cases it is expressed in units of kJ mol-1, measured at 298 K. The most accurate/exact bond enthalpy of a particular chemical on is all dependant on the molecular environment in which the bond exists. The molar bond enthalpy is the energy required to break one mole of bonds between pairs of atoms in the 'gaseous molecule'. Bond enthalpy values are usually expressed in kJ mol-1 of bonds broken. 21/04/14 (http://www.avogadro.co.uk/h_and_s/bondenthalpy/bondenthalpy.htm) Bond making is an exothermic process. However if a certain bond in a molecule is broken and then reformed, then the same amount of energy must be involved. During a chemical reaction bonds in the reactants are broken and new bonds are made in the products. Find H for the following reaction given... ... middle of paper ... ...n -Caution with any glass items Disposal of residues -Extra liquids Colorimetry Colorimetry is the process of determining the concentration of a substance of a substance by measuring the relative of light. The instrument used is called a calorimeter. Colorimetry is the scientific method that is used to classify the colours of the spectrum. (http://www.docbrown.info/page07/appendixtrans09.htm) Background knowledge In chemistry, Colorimetry is used a lot. They use it for things such as colour painting, food manufacturing, and textiles. Colorimetry can also be used to measure light. The amount of light absorbed is called and also is measured as the absorbance which is a use of the coloured solute concentration. To use a colorimeter, different kinds of solutions have to be made, this includes a regulator or orientation of identified concentration.
There is a technique called polarimetry that uses polarized light and asymmetric carbons like those found in glucose. The amount of polaritization can be used to determine the amount of active molecules present in solution.3 The equation used is measured rotation of angle = (a)lc, (a) is optical activity, c is the concentration, and l is the pathlenght. The concept seems similar to Beers
Hess’s Law is also an important concept in this lab. It states that the enthalpy of a reaction is independent of the steps it takes to go from reactant to a product. It happens because enthalpy is a state function. A state function depends on the initial and final state but not the actual process. The Hess’s Law is used to calculate the heat formation of Magnesium Oxide. The amount of heat necessary to create one more mole of a substance is called the Enthalpy of Formation.
Using the spectrophotometer, the absorption of each sample was measured by scanning the wavelengths. After calibrating the spectrophotometer with the blank test tube, each sample was placed into the spectrophotometer and read at 360nm. Observations were continued for each pigment sample increasing the wavelength by 20nm increments. Once these absorbance values were recorded, absorption spectra for each pigment were graphed.
When I dropped iodine to the leaf where I split off from the plant which had waited in red light, its color changed into blue. However, when I dropped iodine to the leaf where I split off from the plant which had waited in green light, its color stayed the same. It is because the plant waited in red light could make more photosynthesis than the other one, so it has more glucose and an iodine solution makes substance’s color blue if it has starch. It is used to test the presence of starch.
The bond energy is a measure of the amount of energy needed to break apart one mole of covalently bonded gases. The SI units used to describe bond energy are kilojoules per mole of bonds (kJ/mol).
Chromatography is a method to distinguish between organic and inorganic compounds so that they can be analyzed and examined. By performing analysis of a compound, a scientist can figure out what makes up the compound. Chromatography related techniques have been used for centuries to separate materials such as colorants extracted from plants. However, Chromatography was first developed in 1900 by Russian scientist Michael Tswett. He continued
The oxygen atom is joined to the hydrogen atom as well as the carbon atom, which makes the oxygen a part of a hydroxyl group. These atoms are generally part of a hydrocarbon chain. These alcohols can take away water from the body, in which a hydrocarbon chain has replaced a hydrogen atom. Alcohols have a general structure of CnH2n+1OH. The aim of this investigation is to see the link between the number of carbon atoms in a fuel with the amount of energy it releases.
The first law of thermodynamics simply states that heat is a form of energy and heat energy cannot be created nor destroyed. In this lab we were measuring the change in temperature and how it affected the enthalpy of the reaction.
The basic principle of the spectrophotometeric technique is the measurement of interaction between energy and electrons of the substance. Spectrophotometric technique is an analytical method used for estimating concentration of metal ion in liquid solution. One of the most magnificent effects of complex formation is the change of spectral properties. The reason for light absorption by complexes are as follows.
-2152.7 x (56.1 / 1.37) = -88150.7 J.mol. 1. H = -88.15 kJ.mol. Hess' law states that: 1"The total enthalpy change for a chemical reaction is independent of the route by which the reaction takes place, provided initial and final conditions are the same.
An endothermic reaction is a chemical reaction in which heat from the surrounding air is incorporated into the reaksie.5 The equation Between baking soda and vinegar are: CH3COOH + NaHCO3 -> CO2 (g) + NaC2H302 (aq) + H20 (1 ) .The reaction releases carbon dioxide release that heat energy required het.Die heat taken from the ambient air that the container in which the reaction occurs cold maak.Die carbon dioxide the pressure / gas provided in gas soda gebruik.6Die temparatuur fall because new bonds are formed and why he so heat energy to take as he needs energy to form the new bonds touch the liquid colder it is still an endothermic reaction. When vinegar with baking soda reacts an endothermic reaction formed. The other equation is: HC2H302-1- NaHCO3 = CO2 (g) + NaC2H3O2 (aq) + H20 (1) .1 Baking soda (NaHCO3) is also known as natruimbikarbonaat. It is
This form of chemical reaction is known as a single displacement reaction and is exothermic. The reaction is irreversible and is written as:
One of the most important things in caliometry is the caliometer. This is a device used to measure the quantity of heat in a reaction. There are many different types of caliometers, some are used to measure the heat capacity of materials, and others measure the aspects the heat generates by new or untested reactions, heat of combustion and burn rates. One type of caliometer is reaction caliometers. These measure heat energy released or absorbed during a reaction that occurs inside the caliometer. Bomb caliometer are used to measure heat of combustion of a particular reaction. Differential scanning caliometers heat flow into a sample is usually measured differentially. A popular caliometer used in biochemistry is called the isothermal titration caliometer. In this caliometer the heat of the reaction is used to follow a titration experiment. It is used in biochemistry because it t facilitates determination of substrate binding to enzymes. Other caliometers that are sometimes used are x-ray micocaliometer, and high-energy particle caliometer. These two caliometers are not as often used, but can still be included in the different types. It is apparent that there are many different types of caliometers and some are used more commonly than others
Hue is the common name for the colours in the spectrum which are red, orange, yellow, green, blue, and violet. A pigment is a colouring ag...
Spectroscopy is measured using a spectrophotometer. A beam of light is first pointed towards the spectrophotometer. The beam of light then strikes a part of the spectrophotometer called the diffraction grating. The diffraction grating works similar to the prism shown above. It separates the light into its component wavelengths by rotating so that only a specific wavelength will reach a part of the spectrophotometer called the exit slit. On the other end of the exit slit there is a sample located in a test tube as well as a detector. After the wavelength passes through the sample, the detector measures the transmittance and absorption of the sample. The transmittance is the amount of light that was able to pass through the sample and reach the detector, and the absorption is the amount of light that was absorbed by the sample. The detector converts the measure of transmittance into s digital display, such as a graph.