chem notes

chem notes - Matter-anything that has mass and can be...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Matter-anything that has mass and can be observed Physical property-variables that don’t change composition when measured e.g. Density , mass, weight , hardness , stiffness , strength Physical change- change in matter that doesn’t alter composition/identity Chemical properties are observed when matter changes composition e.g. chem. reactions Chem. Changes r represented by chem. Rxns e.g. . Combustion of gasoline Phases of matter=solid liquid gas Look at matter macroscopic or microscopic/molecular Macroscopically: Hardness, shape is maintained in solid Liquid adapts to container shape Gas occupies volume of container Matter is made of building blox called elements that form compounds when combined e.g. water co2 gasoline sugar polyethylene Matter is pure substance or mixture Mixture is homogeneous or heterogeneous solutions Pure substances are cmpds and elements Cmpds are polar or nonpolar Hw wed p. 28-29 1.5-1.11 Div. x by x to get 1: Units of measurement kg is official unit of mass mass = measure of the quantity of matter that a substance contains independent of geographic location weight = measure of the gravitational attraction that the earth or other celestial body has on a body with mass m is length unit cubic meter is volume unit J is energy unit Know table 1.6 on p. 19 Atto = 10 to the -18 If u multiply a no. by fract. w/ value of 1, only change form Special 1 only changes unit Ch.2 Molecule is smallest particle of an element that can have a stable independent existence; usually have 2 ore more atoms bonded together Examples of molecules: H 2 , O 2 , S 8 , H 2 O, CH 4 , C 2 H 5 OH Chemical formula doesn’t say who bonds who; structural does Ball and stick model shows where atoms are in space and angles Use smallest amt of sig figs in problems Unit conversions are special 1 problems
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Watch 4 cubes and squares Law of definite proportions aka law of constant composition = formula contains same ratio every time OFLeT: observation is percentages, - Dalton’s atomic theory p. 6 Observations, facts, laws, Atoms have mass Atomic weights are weighted average put under symbol on periodic table All based on Carbon-12 Mole is a # and a weight One mole = 6.02 * 10^23 Atomic mass of every element in amu is 1 mol of every element in grams 8 million CH 4 molecules to # of grams: 1 carbon = 12.011 amu, 4 H = 4(1.008) amu, total molec. Weight is 16.00 amu 1 mol methane is 6.02*10^23 and 16.00 g homework due Wed. % composition: mass of el. In cmpd. Divided by mass of cmpd. Times 100% Determine % compo. Of C in C3H8. %C = (mass C/ mass C3H8) * 100% = (3*12.01 g/44.11 g)*100% = 81.68% simplest formula- from el. % to molar ratios How many mol in 20.0 g elemental H? 20 mol Determine the empirical formula of a salt made from Al, C and O. 23.1% is Al, 15.4% is C, and 61.3% is O. Al?C?O?
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/21/2008 for the course CM 1113 taught by Professor Hutchinson during the Fall '07 term at Lipscomb.

Page1 / 12

chem notes - Matter-anything that has mass and can be...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online