PreparED Study Materials
CHEM 145: Introductory Chemistry
School: University of Illinois
Number of Notes and Study Guides Available: 0
Videos
Protons reveal electron count in atoms. Which statement applies?
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In this video, we explore the information that knowledge of the number of protons in a neutral element's atom can provide. Options for determining neutron count, electron count, and identifying the element's name are examined, with a conclusion that it allows us to know both the number of electrons and the element's name.
The Wobble Concept: Explaining Codon Variability in Amino Acid Encodin
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Join us as we delve into the intriguing world of genetic coding and discover how the concept of wobble accounts for variations in codons encoding a single amino acid.
Calculating Formula Masses: From Barium Bromide to Hydrobromic Acid
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Understand the process of calculating formula masses for various compounds. This video breaks down the atomic masses for elements in barium bromide, dinitrogen trioxide, copper(I) sulfate, and hydrobromic acid. Master the method of summing up the masses considering atom count in each formula.
Molecule Count in 0.334 g of C?H?: Ethane Analysis
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This instructional video guides you through the process of determining the number of molecules in a given sample. It illustrates the conversion from grams to moles using the molar mass of the substance and then to molecules using Avogadro's number, providing a practical example with ethane (C?H?) to calculate approximately 6.67 x 10²¹ molecules in a 0.334 g sample.
Drawing Open-Chain Structures: A Visual Guide to Four Sugars
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Learn how to draw open-chain structures for various sugars, from ketotetrose to amino sugars. This video offers visual demonstrations of ketopentose, deoxyaldohexose, and more, highlighting key molecular differences.
Determining Base Concentration Using KHP: Indicator Choice Solution
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Discover how to choose the right indicator for a titration involving Potassium hydrogen phthalate (KHP) and a strong base. Grasp the calculations from molar mass to pH and understand why Thymolphthalein is the ideal choice for a change near pH 8.95.


















