Allotropy
Allos in Greek means other and “tropos” in Greek means form. Allotropes are different physical forms of the same element. All elements are made up uniquely of their own atoms and therefore any physical differences must be a consequence of how the atoms are joined together - their arrangement within the bulk structure. Many elements exhibit allotropy as there are often various ways in which the atoms can be linked together into molecules and also different ways in which the molecules can be arranged to make larger structures. The following are allotropes of Carbon
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From the handbook
The quality of the crystal is judged on a scale of 1 to 10, with 10 representing a perfect crystal. The following factors will be considered in judging quality: • match/mismatch with crystal type (out of 2) • presence/absence of occlusions (out of 2) • intact, clean and well-defined/broken, rounded edges (out of 2) • well-formed/misformed faces (out of 2) • clarity/muddiness (out of 2) Total Observed Quality Qo = x.xx (out of 10) The Total Score is then determined as follows: Total Score = [log (Mo+1)] x Qo The logarithm of the mass is chosen so that large poor quality crystals do not swamp out smaller good quality crystals. The value 1 is added to the mass so that crystals weighing less than 1 g get a positive score. A 100 per cent yield crystal made from 100 g (MMAX) that scores a perfect 10 on quality (QMAX) would get a theoretical maximum of: [log (100+1)] x 10 = 20.01 The actual score is expressed as a percentage of the maximum. The crystal with the highest Overall Score is the winning crystal. 100 x {[log (Mo+1)] x Qo} / {[log (MMAX+1)] x QMAX} = Overall Score % A perfect crystal weighing 100 g would get a score if 100%. Example: The best overall crystal in the 2001 contest with 150 g starting material (MMAX = 150 g) weighed 46.53 g and had a quality of 8.65. Its overall score was: 100 x {[log (46.53+1)] x 8.65} / {[log (150+1)] x 10} = 66.6%
Read the handbook on growing crystals.
Look up MSDS and solubility of CuSO4 5H2O Finish the scientific notation WS if you didn't in class. Finish the 1.3 review questions from the workbook. Quiz on sig fig next class Quiz on measurement with uncertainty next class.
Do the reading for the crystal growing project. Sign up for join the AP classroom online. |
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November 2019
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