Chapter 1: Chemical FoundationsAIM: By the end of this chapter, you are expected to have

reviewed:1. the scientific method

2. measurements (uncertainty, significant figures, rules, dimensional analysis)

3. Classification of matter

. Do Now: 1. Differentiate between qualitative and

quantitative observations/data.2. True or False (explain why): A theory

can be proven correct or incorrect

1.1 Chemistry: An OverviewConsidered the “central” scienceALL matter and energy transformations are

based on interactions between atoms and molecules

Macroscopic vs. submicroscopic viewsScience: a process for understanding the

natural world and its changes

1.2 Scientific MethodMaking observations

Qualitative Observations - observations made by using your senses (does not involve a number)

Quantitative Observations - observations made by measuring (involves a number and a unit)

Formulating hypotheseshypothesis - a possible explanation for an observation

Performing experimentsexperiments - performed to test the hypothesis.

Experiments will either support or disprove your hypothesis.

Forming a theory - set of hypotheses that agree with observations over the test of time. Helps create a model.

1.3 Units of MeasurementMetric System: ALL measurements in this

course are expected to be reported in the metric system

MeasurementsNumber and Scale (units) are both essential"The number without the units is worthless!“

SI systemImportant SI Units for Chemistry

Mass kilogram kgLength meter mTime second sTemperature Kelvin KAmount of Substance mole molVolume liter L

SI PrefixesMega M 1,000,000 106

Kilo K 1,000 103

Hecto H 100 102

DekaD 10 100

Deci d .1 10-1

Centi c .01 10-2

Milli m .001 10-3

Nano n .000 000 001 10-9

Pico p .000 000 000 001 10-12

**KNOW TABLE 1.2 (page 9)**

1.4 Uncertainty in MeasurementEvery measurement always has some degree of uncertainty.

When measuring it is always important to record the certain digits (those that are marked on the measuring device) and the

first uncertain digit (not marked on the device and the number is guessed at).

Accuracy - refers to the agreement of a particular value with the true value.

Precision - refers to the degree of agreement among several measurements of the same quantity.

Random error - means that a measurement has an equal probability of being high or low.

Systematic error - this error occurs in the same direction each time; it is either always high or always low.

1.5 Significant Figures and CalculationsNonzero integers - nonzero integers always count as

significant figures.Zeros - depending on the type of zero, it will determine

weather the zero counts or does not.Leading zeros - are zeros that precede all the nonzero

digits. these do not count as significant figures, they are considered place holders.

Captive zeros - are zeros between nonzero digits. These always count as significant figures.

Trailing zeros -are zeros at the right end of the number. They are significant only if the number contains a decimal point.

Exact numbers - numbers that were not measured but determined by counting. These can be assumed to have an infinite number of significant figures.

Mathematical OperationsFor multiplication or division - the

number of significant figures in the result is the same as the number in the least precise measurement used in the calculation.

For addition or subtraction - the result has the same number of decimal places as the least precise measurement used in the calculation.

RoundingIn a series of calculations, carry the extra

digits through to the final result, then round.If the digit to be removed -

is less then 5, the preceding digit stays the same.

is equal to or greater than 5, the preceding digit is increased by 1.

1.6 Dimensional Analysismethod used to change from one system of

units to another.Converting from one unit to another

To convert from one unit to another, use the equivalence that relates the two units.

Derive the appropriate unit factor (equivalence factor) by looking at the direction of the required change (to cancel the unwanted units)

Multiply the quantity to be converted by the unit factor to give the quantity with the desired units.

1.7 TemperatureKnow the relationship and conversion between the

three systems for measuring temperatureKelvin (K)Celcius (oC)Farenheit (oF)

Celsius (°C) and Kelvin (K)Kelvin = Celsius + 273.15Celsius = Kelvin - 273.15Size of the temperature unit (degree) is the same

FahrenheitTC = (TF - 32°F)(5°C/9°F)TF = TC x (9°F/5°C) + 32°F

1.8 DensityDerived unitBased on relationship between mass and

volumeD = M/VDependent on temperature

WHY? NOT dependent on amount or quantity of

sample used

1.9 Classification of matterMatter

Anything that occupies space and has massStates of Matter

Solids - rigid, fixed volume and shapeLiquids - definite volume, no specific shapeGases - no fixed volume or shape, highly

compressibleMixtures - Matter of variable composition

Heterogeneous mixtures Having visibly distinguishable parts

Homogeneous mixtures (solutions) Having visibly indistinguishable parts

Components of Mixtures can be Separated by Physical MeansDistillation-difference in volatilityFiltration-solid/liquidChromatography—difference in polarity

Pure substancesElements

Cannot be decomposed into simpler substances by physical or chemical means

Compounds Constant composition Can be broken into simpler substances by chemical

means, some physical means

HOMEWORK 1- Due Mon 9/101. A student performed an analysis of a sample for

its Iodine content and got the following results.19.3%, 21.2%, 18.7% and 20.4%The actual value is 20.3%. What can you say about the student’s accuracy and precision? What can you say about the cause(s) for any error?

2. Is the boiling of water a physical or chemical change? Explain

3. Textbook Questions 29a,b, 31a,b, 33a-d, 35c, 43, 45

Homework 2-Due Wed 9/12Textbook Questions, Chapter 1

# 15, 47, 53, 59, 63, 67, 69, 77,