Homework assignment Due 9/12/06 Chapter 1 –18, 22, 32, 39, 46, 50, 55, 66

CHE107 Lab Organization Starts Monday (9/11/06) Meet here You need (ie. bring to lab)… –Lab manual (Red) –Bound lab notebook –Safety goggles –Close-toed shoes (Safety 1 st !!)

Before lab: –Read the section of the lab manual –Answer the pre-lab questions (p.15) These are to be handed in at the beginning of lab! –Start your lab notebook Title, purpose, procedures, balanced equation(s), etc. CHE107 Lab Organization

During lab –Write down observations (measurements, etc) in your notebook –Follow your written procedures –Write down changes to the pre-lab procedures CHE107 Lab Organization

After lab –Write lab report, including post-lab questions Grading –Pre-lab questions –Lab report –Laboratory notebook (midterm & final) “Disco Lab” Wednesday 1:30-4:20 CHE107 Lab Organization

Next week’s lab: “The Bean Lab” Series of measurements –Average/mean –Standard deviation How much do your values ‘vary’? –Differences in individual –Errors in measurements

Mean/Standard deviation calculations: –Hand –Calculator –Computer (Excel spreadsheet)

Simplifying numbers…Prefixes Simplify 30,000 m. 30 mm is how many meters (m) ?

Simplifying numbers: Scientific Notation The number of atoms in 12 g of carbon: 602,200,000,000,000,000,000, x The mass of a single carbon atom in grams: x N x 10 n N is a number between 1 and 10 n is a positive or negative integer

Scientific Notation n > = x 10 2 move decimal left n < = 7.72 x move decimal right N x 10 n

Scientific Notation Addition or Subtraction 1.Write each quantity with the same exponent n 2.Combine N 1 and N 2 3.The exponent, n, remains the same 4.31 x x 10 3 = 4.31 x x 10 4 = 4.70 x 10 4

Scientific Notation Multiplication 1.Multiply N 1 and N 2 2.Add exponents n 1 and n 2 (4.0 x ) x (7.0 x 10 3 ) = (4.0 x 7.0) x ( ) = 28 x = 2.8 x Division 1.Divide N 1 and N 2 2.Subtract exponents n 1 and n x 10 4 ÷ 5.0 x 10 9 = (8.5 ÷ 5.0) x = 1.7 x ,000 x =4.2 x 10 2

Dimensional analysis –Convert units 3.5 days = x seconds ? Working with numbers Gen Chem edition

1.9 Dimensional Analysis Method of Solving Problems 1.Determine which unit conversion factor(s) are needed 2.Carry units through calculation 3.If all units cancel except for the desired unit(s), then the problem was solved correctly. 1 L = 1000 mL How many mL are in 1.63 L? 1L 1000 mL 1.63 L x = 1630 mL 1L 1000 mL 1.63 L x = L2L2 mL How many seconds in 3.5 days? x 10 5 seconds

The speed of sound in air is about 343 m/s. What is this speed in miles per hour? 1 mi = 1609 m1 min = 60 s1 hour = 60 min 343 m s x 1 mi 1609 m 60 s 1 min x 60 min 1 hour x = 767 mi hour meters to miles seconds to hours

Density – SI derived unit for density is kg/m 3 1 g/cm 3 = 1 g/mL = 1000 kg/m 3 density = mass volume d = m V A piece of platinum metal with a density of 21.5 g/cm 3 has a volume of 4.49 cm 3. What is its mass? d = m V m = d x V = 21.5 g/cm 3 x 4.49 cm 3 = 96.5 g

Three Temperature Scales Fahrenheit Celcius (Centigrade) –Absolute zero = °C Kelvin (K) (SI unit) –Absolute zero = 0 K

K = 0 C F = x 0 C K = 0 0 C 373 K = C 32 0 F = 0 0 C F = C

Atoms, Molecules and Ions Chapter 2 Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Dalton’s Atomic Theory (1808) 1. Elements are composed of extremely small particles called atoms. All atoms of a given element are identical, having the same size, mass and chemical properties. The atoms of one element are different from the atoms of all other elements. 2. Compounds are composed of atoms of more than one element. The relative number of atoms of each element in a given compound is always the same. 3. Chemical reactions only involve the rearrangement of atoms. Atoms are not created or destroyed in chemical reactions. 2.1

2

8 X 2 Y 16 X8 Y + 2.1

atomic radius ~ 100 pm = 1 x m nuclear radius ~ 5 x pm = 5 x m Rutherford’s Model of the Atom 2.2 “If the atom is the Houston Astrodome, then the nucleus is a marble on the 50-yard line.”

mass p = mass n = 1840 x mass e - 2.2

Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutrons Isotopes are atoms of the same element (X) with different numbers of neutrons in their nuclei X A Z H 1 1 H (D) 2 1 H (T) 3 1 U U Mass Number Atomic Number Element Symbol 2.3

6 protons, 8 (14 - 6) neutrons, 6 electrons 6 protons, 5 (11 - 6) neutrons, 6 electrons Do You Understand Isotopes? 2.3 How many protons, neutrons, and electrons are in C 14 6 ? How many protons, neutrons, and electrons are in C 11 6 ?