Matter and MeasurementCh 1 Brown, LeMay

The Basics (1.2 & 1.3)• States of Matter• Solid• Liquid• Gas• Plasma• Bose-Einstein Condensate (BEC)

• Particle Spacing• Particle Movement• Energy

Classification of Matter

Classification of Matter

Classification of Matter

Classification of Matter

Classification of Matter

Classification of Matter

Classification of Matter

Classification of Matter

Classification of Matter

Properties and Changes of Matter

Types of Properties• Physical Properties…• Can be observed without changing a substance into another

substance.• Boiling point, density, mass, volume, etc.

• Chemical Properties…• Can only be observed when a substance is changed into another

substance.• Flammability, corrosiveness, reactivity with acid, etc.

Types of Properties• Intensive Properties…• Are independent of the amount of the substance that is present.

• Density, boiling point, color, etc.

• Extensive Properties…• Depend upon the amount of the substance present.

• Mass, volume, energy, etc.

Separation of Mixtures

Hand Separation• Separate a mixture like this…

• …by using your hand!

Filtration• In filtration solid

substances are separated from liquids and solutions. What remains on the filter paper is called the “precipitate” and what passes through is called the “filtrate.”

Separating Funnel

Shake and let

sit…

Usually used to separate immiscible liquids, like oil and water mixture.

Centrifuge

Place in centrifuge…

Separates particles of different masses based on centrifugal force. Heavier particles settle at the bottom followed by the lighter particles on top.

Distillation• Distillation uses

differences in the boiling points of substances to separate a homogeneous mixture into its components.

ChromatographyThis technique separates substances on the basis of differences in solubility in a solvent

S.I. – The Metric System (1.4)

Uncertainty

• Precision: how closely individual measurements agree with one another; the “fineness” of a measurement

• Accuracy: how closely individual measurements agree with the “true” value

• Significant Figures: for any measurement, all the digits that are “certain” plus one “uncertain” digit, an indication of precision

Determining Significant Figures

• 1. Any nonzero digit is significant.• 457 cm = 3SF 29cm = 2SF

• 2. Any zero between nonzero digits is significant.• 1005 kg = 4SF 807 = 3SF

• 3. Any zero in front of a number is not significant; it’s a placeholder.• 0.0026 Å = 2SF 0.41 Å = 2SF

Anders Ångström(1814 – 1874)

Determining Significant Figures

• 4. Any zero at the “end” of a number & there is a decimal point in the number is significant.• 0.05000 K = 4SF 3000 K = 1SF 7000.K = 4SF

• 5. For exact numbers (e.g. 4 beakers) & those used in conversion factors (e.g. 1 inch = 2.54 cm), there is no uncertainty in their measurement and are considered to have infinite significant figures.

• For more practice: http://lectureonline.cl.msu.edu/~mmp.applist/sigfig/sig.htm

Calculating with Sig Figs

• 1. Addition & Subtraction: a sum or difference has the same number of decimal places as the measurement with the fewest decimal places.• 15.047 g + 4.12 g = ?

• 25,040 mL + 37,200 mL = ?

15.047+ 4.12 19.167 19.17g

25,040 mL+37,200 mL 62,240

62,200mL or 6.22 × 104 mL

Calculating with Sig Figs

2. Multiplication & Division: a product or quotient may be no more significant than the least significant measurement. Use the least significant figures.

3.000 × 4.00 = 12.0(4SF) (3SF)= (3SF)

3. Logarithms: retain in the mantissa (the decimal part of the logarithm) the same number of Sig Figs there are in the original value.

log (3.000 × 104) = 4.477121255 = 4.4771log (3 × 104) = 4.477121255 = 4.5

Calculating with Sig Figs

• 4. Series of Operations: keep all non-significant digits during any intermediate calculations, and round to the correct number of significant figures at the end.

(4.5 + 3.50001) × 2.00 = (8.00001) × 2.00 = 16.0002 = 16

Rounding Rules for Significant Figures

• 1. Look at the leftmost digit of the numbers you are removing, if it is less than 5, don’t round the last sig fig up.• Ex. 7.248 rounded to two SF would be 7.2

• 2. If the leftmost digit of the numbers you are removing is 5 or greater, round the last sif fig up.• Ex 4.735 rounded to three SF would be 4.74

Dimensional Analysis (1.6)• Is an aid when solving problems based on cancelling out the

units you don’t need in favor of those you do need.• Uses conversion factors

• Given unit × desired unit = desired unit given unit