CAS CH 101 Lecture Notes - Lecture 2: Carbon-12

• School: Boston University
• Department: Chemistry
• Course: CAS CH 101
• Professor: Dan Dill

Document Summary

Ch 101 lecture 2 atomic mass unit, isotopes, atomic weights and the mole. Assumptions: 75. 5% of the air density is n2, the liquid density of n2 is the following: 0. 808 g/cm3. Steps/solution: take away: while atoms are small, they take up space. 1/12 of the mass of carbon-12 (definition) 12g of carbon-12 contains 6 x 1023 atoms (fact) There is 12g with 6 x 1023 objects. 1u = x 1. 99265 x 10-23g = 1. 66054 x 10-24g. Mass of 1 carbon-12 atom = 1. 99265 x 10-23g. Atomic mass: average mass of atoms in atomic mass units. Isotopes: same amount of protons, but different amount of neutrons chemically the same, however different masses. Relative atomic weight is the average mass of the different kinds of atoms (isotopes). Strips away electrons, accelerate ions, deflects them in a magnetic field. What is the average mass of ch 101 students: 75 students weigh 100lbs, 100 students weigh 150lbs, 50 students weigh 200lbs.