CH 111, Week 2 Notes
CH 111, Week 2 Notes CH111
Popular in General Chemistry 1
Popular in Chemistry
This 4 page Class Notes was uploaded by Jordyn Meekma on Tuesday September 27, 2016. The Class Notes belongs to CH111 at Northern Michigan University taught by Dr. Tom Getman in Fall 2016. Since its upload, it has received 3 views. For similar materials see General Chemistry 1 in Chemistry at Northern Michigan University.
Reviews for CH 111, Week 2 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/27/16
CH 111 Notes: Week 2 Significant Figures o Integers: all integers are significant 24.7 = 3 sig figs o Zeros: Zeros at the beginning of a number are never significant 0.47 → 0 is not a sig fig (2 sig figs) Zeros at the end of a number after a decimal are always significant 1.50 → 0 is a sig fig (3 sig figs) Zeros between two nonzero integers are always significant 3.506 → 0 is a sig fig (4 sig figs) Zeros at the end of a number with no decimal may/may not be significant 2 300 = ? *Need to use scientific notation* 3.00x10 = 3 sig figs o Multiplication/Division: the answer should have the same number of sig figs as the number with the least amount of significant digits 97.11/2.50 = 38.8 = 3 sig figs o Addition/Subtraction: the answer should have the number of sig figs as the measured number with the fewest digits to the right of the decimal 0.2817 + 0.61 = 0.89 Practice Problems o What is the mass of a gold bar with dimensions 10.0 cm x 5.25 cm x 3.50 cm? (Density of gold = 19.3 g/cm ) 3 → (19.3 g/cm )( 10.0 cm x 5.25 cm x 3.50 cm) = 3550 g = 3.55x10 g 3 (3 sig figs) o If you have a 500.0 mg vitamin that contains 25.0 micrograms of Vitamin E, what is the mass percent of Vitamin E? → (25.0 micrograms/500.0 mg)(1g/10 micrograms)(1000mg/1g) x100% -3 = 5.00x10 % If the recommended dose of Vitamin E is 10.0 micrograms, what is the percent of the recommended dose in 1 tablet? 2 → (25.0 micrograms/10.0 micrograms)x100% = 2.50x10 % Chapter 2: Atoms, Ions, and Molecules Subatomic Particles Particle Abbreviat Mass Charge ion Neutron n About 1 0 (neutral) amu Proton p About 1 +1 amu Electron e- About 0 -1 amu o amu = Atomic Mass Unit 1 amu = 1.66054x10 -27kg Atom Electron Cloud Nucle us Atomic Number: Number of protons in an atom’s nucleus, specific to each element weighted average mass of isotopes Isotope: atoms of the same element that differ in the number of neutrons 12C vs. 1C Mass Number: total number of protons and neutrons o If the element is neutral, it will have the same number of electrons as protons Practice Problems o Boron has two isotopes: 10B (10.012937 amu) and 1B 10 11 (11.009305 amu). B has a prevalence of 19.9% and B has a prevalence of 80.1%. What is the average mass of Boron? → (10.012937 amu)(0.199) + (11.009305 amu)(0.801) = 1.99 + 8.82 = 10.81 amu o The average mass of Argon is 39.948 amu (from the periodic table). It has 3 isotopes. 3Ar: 35.96755 amu, prevalence of 38 40 0.337%, Ar: 37.96272 amu, prevalence of 0.063%, and Ar: ? amu, prevalence of 99.60%. Find the mass of 40Ar. → 39.948 amu = (35.96755 amu)(0.00337) + (37.96272 amu) (0.00063) + (0.9960)x x = 39.96275 = 39.96 amu Covalent Bonds: one or more electron pairs are shared between atoms Ionic Bonds: attraction between a positively charged ion and a negatively charged ion o Cation: positively charged ion o Anion: negatively charged ion Molecular Compound: atoms held together by covalent bonds Ionic Compound: atoms held together by ionic bonds Molecular Formula: a notation showing the number and type of each atom in a molecule o CO 2 O=C=O (each line represents a bond → a pair of electrons that are being shared) Charges of Elements in Compounds o Alkali Metals: Group 1A (+1) o Alkaline Earth Metals: Group 2A (+2) o Group 3A (+3) o Transition Metals: vary, except… Ag (+1) Cd (+2) Zn (+2) o Group 5A: (-3) o Group 6A: (-2) o Halogens: (-1) o Noble Gases: neutral Naming Ionic Compounds o *a metal + a nonmetal* o The end of the anion ends with –ide MgCl 2 Magnesium Chloride o If the cation has multiple possible charges (transition metals usually), it is denoted in roman numerals → I = +1, II = +2, III = +3, IV = +4, etc… CrCl3→ Chromium (III) Chloride Naming Covalent Compounds o *2 nonmetals* o The more electropositive atom is written first and the more electronegative element is written last with an -ide suffix o Elements have a prefix based on the number of atoms of each element in the compound Mono- → one Di- → two Tri- → three Tetra- → four Penta- → five Hexa- → six Hepta- → seven Octo- → eight Nona- → nine Deca- → ten o If there is only one of the first element, you can drop the prefix o If there are two vowels in a row that conflict, the extra vowel on the end of the prefix is removed o NF → Nitrogen trifluoride 3 o CO → Carbon monoxide o N 2 4 Dinitrogen tetrahydride
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'