3. Explain why It ts necessary to cattbrate the spectroscope, and briefly outine
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3. Explain why It ts necessary to cattbrate the spectroscope, and briefly outine the procedure that you will use to do this. An example of a calibration process is the following: Thermocouples can be used to measure temperature when it is not practical to do so with a thermometer. Thermocouples measure temperature in terms of voltage, rather than directly on a temperature scale and therefore need to be calibrated. Comparing the thermocouple output with the reading from a highly accurate thermometer allows the correlation between voltage and temperature. Based on the calibration curve below, what is the temperature of a substance measured with a thermocouple reading of 0.498 VI Thermocouple Calibration 45 030 035 40 s as 4. When heated in a flame, impart a lilac color to the flame. Explai Read and complete the following activity: sodium salts produce a golden-yellow color while potassium salts in why different colored flames are observed. 5. Have you ever gazed up at the stars and wondered: How did they form? What are they made of? are some brighter colors (as shown by Hubble telescope photos, for example)? Why than others? How far away are they? How hot are they? Why are stars different Astronomers measure the intensity and wavelength of light given off by these massive balls of gas to answer many of these questions. A star's blackbody radiation curve tells astronomers how hot the is (which also corresponds to the star's color). It also tells them what stars are made of The star's spectrum has regions where the intensity of light decreases. These dips are due to absorption of photons by ions and atoms that make up and surround the star. The star's composition can be determined by comparing the wavelengths of those dips to absorption spectra of the elements. Your Challenge: To translate atomic emission and absorption spectra on the following page into energy level diagrams for element X Two copies of the activity are provided for you. Use the one on the reverse side of this page fo practce ad fr your records. Do your final work directly on the second copy and submit it wit your pre-lab.Explanation / Answer
3. Like any other analytical instruments, spectroscopes (I assume you are talikng about UV-Vis spectrophotometer) need to be calibrated in order to get accurate absorbance and absorbance wavelength of unknown samples.
There are two aspects of calibrating spectrophotometer; absorbance (more common) and wavelength (less common).
To calibrate absorbance,
i). Choose a material (calibration standard) which has sharp absorption peak. Absorption wavelength and absorbance values should be available in the literature or in the calibration standard kit.
ii). Prepare a series of solutions with known concentrations and measure the absorbance at the absorption wavelength.
iii). Plot absorbance vs. concentration graph. It should be a straight line passing through (0,0), with R2 close to 1. The slope of the straight line should match with the slope provided in the calibration standard kit.
iv) If the two slopes match, then the spectrophotometer is is good shape. If not, then we need to include a correction factor (ratio between observed and provided value of slopes).
As thermocouple correlates between temperature and voltage, spectrophotometer corelated between concentration and absorbance. Therefore, in order to find concentration of an unknown sample from its absorbance value, it is highly important to have a standard calibration curve (Absorbance vs concentration). Suppose you want to measure concentration of permanganate solution of unknown strength. Prepare a series of solutions with known concentration. Measure their absorbance. Plot absorbance vs concentration. Get the equation for the straight line passing through origin (0,0). Calculate concentration for any given value of absorbance.
To answer the question regarding thermocouple calibration,
y= 49.532x + 16.443, where temperature is Y and thermocouple reading is x.
When, x = 0.498 V, y = (49.532 * 0.498) + 16.443 = 41.110 C.
4. While heating, outer electrons of metals go to an excited state. As they fall back to their original unexcited states (either in one or in multiple steps), energy is released as light. Each of these electronic jumps involves a specific amount of energy released in terms of light, which corresponds to a particular wavelength or frequency.
Because of different electronic configuration of different metal atoms, they emit lights of different wavelength and show different colors.
5. Can not be answered as required informations are missing.
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