Chapter 1 Matter and Measurement CHM 108 SUROVIEC FALL 2014

Chemistry is concerned with matter and energy and how the two interact with each other Chemistry is a foundation for other disciplines  Engineering – polymers, energy, pharmaceuticals  Health sciences  Pharmacy and pharmacology  Scientific writing Chemistry

I. Atoms and Molecules 3 Air is made of several components Atoms are particles that constitute the fundamental building block of matter Molecules are 2 or more molecules joined together

I. Atoms and Molecules 4 Properties of various substances depend on the molecules and atoms that make them up H 2 O vs H 2 O 2

II. Classification of Matter Matter has mass  Not the same as weight Matter occupies space Phases of matter  Solids  Fixed volume and shape  Liquids  Fixed volume, indefinite shape  Gases  Indefinite shape and volume

B. Elements/Compounds/Mixtures 6 Besides classifying by state also classify by composition Starting with all matter ask does the composition vary if you took 2 samples Pure substance Mixtures

Classification of Matter

III. Physical and Chemical Changes 8 We are constantly seeing changes in matter:  Evaporate, rust, rotting, freezing, etc But what happens to the molecules during these changes?

II. Physical and Chemical Changes physical change: does not alter the composition or identity of a substance. chemical change: alters the composition or identity of the substance(s) involved.

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IV. Units of Measurements 11 In 1999 the US and European scientists working together on the Mars Climate Orbiter realized after they had all ready sent the satellite off that half of the measurements were in metric and half in English. The satellite was lost.

Table Powers of Ten

Table 1.3 – Units and Unit Relations

IV. Units of Measurements 14 A. Meter and LengthB. Kilogram and Mass

IV. Units of Measurement 15 C. Time and secondsD. Temperature and Kelvin

E. Volume and Density 16 Volume is measurement of space and length 3 Density  Ratio of mass to volume

V. Reliability of Measurement 17 If we were to measure water using a beaker an then again with a graduated cylinder: Scientific measurements are reported so that every digit is certain except the last This digit is an estimate

V. Reliability of Measurements Significant Figures  Every measurement carries uncertainty  All measurements must include estimates of uncertainty with them  There is an uncertainty of at least one unit in the last digit Significant figures are meaningful digits in measurements  In 8.00 mL, there are three significant figures  In 8.0 mL, there are two significant figures  In 8 mL, there is one significant figure

A. 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

A. Scientific Notation Convert the following to scientific notation: m (diameter of Na atom) 150,000,000m (distance from Earth to moon)

Accuracy – how close a measurement is to the true value Precision – how close a set of measurements are to each other accurate & precise but not accurate & not precise B. Precision and Accuracy

VI. Unit Conversion In many cases throughout your study of chemistry, the units (dimensions) will guide you to the solution of a problem Always be sure your answer is reported with both a number and a set of units!

VI. Unit Conversions Conversion factors are used to convert one set of units to another  Only the units change  Conversion factors are numerically equal to 1  1L = 1000 cm 3

VI. Unit Conversion Conversion Unit 1 x pg = 1 g Convert 1.00 mg into picograms How large is Australia in sq meters if 1 mile = meters and the land mass = 2,941,526 sq. miles? How much does a person weigh in pounds if they weigh stone, given that 1 stone = 14 pounds. Use significant figures.

A. Problems with Equations 25 With these problems you are going to find one of the variables given the rest. Find the radius in cm of a water droplet with a volume of 0.06cm 2 using V = (4/3)  r 2