# Chem 403 class 4

 The flashcards below were created by user mmb65 on FreezingBlue Flashcards. 1.00 grams equal how many mass units 6.022 x 1023 What is Avogadro's number? 6.022 x 1023 one mole of an element is......... atoms of an element 6.022 x 1023 one mole of a compound is............moles of the compound 6.022 x 1023 moles to grams ﻿﻿Mass (g) + # moles x # grams mole grams to moles # moles+ # grams x moles # grams formula to convert number of moles to the actual number of atoms or molecules of a substance using Avogadro's number # molecules= # mol x (6.022 x 1023) molecules mole To convert from weight to # of molecules first....... the weight to moles then use Avogadro's # to determine the # of molecules What can you calculate after you know that mass %? you can calculate the fraction of a given weight of a compound due to a particular element. Determining the formula of an unknown compound: how do you do this? by converting masses to moles, then determine the ratio of the elements in the compound Whenever you are given a percentage of an element, you can.... assume any weight you want (100 is the easiest) quickly how would you solve this: A 0.2500g sample known to contain C, H, O is burned completely producing 0.3664g CO2 and 0.1500g H2O Mass of CO2 x mass fraction C in CO2 What are isomers? different compounds with the same molecular formula molecules to the left of the arrows are reactants molecules to the right of the arrow are products to satisfy conservation of mass the equation has to be balanced Two molecules of H2 react with one molecule of O to form 2 molecules of H2O. Can also be read as: Two moles of H2 react with 1 mole of O2 to form 2 moles of H2O. Limiting reactant: the reactant that runs out first excess is the compound you are left over with after the limiting reagent stops the reaction Authormmb65 ID21066 Card SetChem 403 class 4 DescriptionNotes from class 4 chem 403 Updated2010-05-28T20:13:47Z Show Answers