Chemistry !! The study of the composition, __________, and properties of matter and the ____________________ Chemists make measurements to ________________ of matter. To keep things consistent, we all work in __________

Scientific Method

Definitions ___________ – a testable statement ______ – an explanation of how phenomena occur and how data and events are related _________ – a broad generalization that explains a body of facts

Equipment Commonly used for liquid measures

Liquid Volumes Volume read to the bottom of the _________

SI Units? Measurements can be made in many different units. To be consistent, all scientists use the metric system to report measurements. Metric system units are called SI Units

SI Units Examples MeasurementUnitAbbrev. massgram lengthmeter volumeliter timesecond temperature Kelvin energyJoule Amount of sample Moles

Temperature Conversions Like most measurements, temperature has many forms. There are three common ways to report temperature: Fahrenheit (  F ), Celsius (  C ), and Kelvin (K ). K =  C or  C = K  F = (1.8)(  C ) + 32

Temperature Conversion? So, if it is 35  C, would you go skiing or swimming? What is the temperature in  F ? In K ? ____  F ____ K

SI Subunits PrefixAbbrev.Factor MegaM-1 x 10 6 KiloK-1 x 10 3 HectoH-1 x 10 2 DekaD-1 x 10 1 Base Unit – meter (m), liter (l), or grams (g) deci-d-1 x centi-c-1 x millim-1 x micro-  1 x nano-n- 1 x pico-p- 1 x

Metric Conversions Meter (m) Liter (l) Gram (g) Joule (J)

Unit Conversion? In Chemistry, we can make measurements in many different units. So, we often need to convert to another set of units. We need three things: 1. where you are __________ 2. where you are _______, and 3. the __________________ to get you there.

Converting Units Example To convert units you need to know where you are starting, finishing, and the conversion factor. Find the number of cm in 2.1 meters. We know: 1 m = 100 cm 2.1 m 100 cm = ____ cm 1 m

Find the number of  g in 8,200 g. We know: 1000 g = 1  g 8,200 g 1  g = ____  g 1000 g Converting Units

SI Subunits Conversions 10.5 g=_________ kg 1.57 km= _______ m 3.54 mg=__________ g 3.5 J=_________ DJ 1.2 L=_____ ml 358 cm=_________ m

How many cm are in 2.8 inches. Conversion Factor: 1 in = 2.54 cm 2.8 in cm = ____ cm in How many inches in 12.4 cm? 12.4 cm in = ____ in cm Converting Units

Unit Conversion Examples How many ounces in 600 mls? mls oz = ______ oz mls First we need conversion factor ! 12 oz. = 355 ml

Converting Time How many days are there in 52,480 minutes? = ______ days How many minutes are there in 2.4 months? = ___________ minutes

Converting Weird Units If 4.2 rens = 1.0 blip rens = 1.0 talp Find the number of talps in 13.5 blips Ans: _______ talps ________ talps Correct significant #s

Converting Units If 4.2 rens = 1.0 blip rens = 1.0 talp a)Find the number of rens in talps. b)Find the number of talps in 155 blips. c)Find the number of talps in 32 blips __________ ___________ _________

Conversions with two units If you are traveling 20 miles/hour, how many meters/seconds is this? Change one unit at a time. Note, many ways to do this.

Conversions with two units Convert 25 miles/gallon to km/liter Convert 10 kg/liter to g/ml = ______ km/l = ______ g/ml

Precision vs. Accuracy

Accuracy and Precision _________ _______ _______________ _________

Precision Refers to the closeness of a set of measurements __________ Requires that ____________ measuring the same thing be done Example: – 2.22,2.23,2.21 shows good precision

Accuracy Refers to how close an answer ________ is to __________ or correct value Requires that the accepted value is ______ Use ___________ to express accuracy

Percent Error _________ = experimental value – accepted value (value can be _______ or ________) ___________ experimental value – accepted value x 100 accepted value (absolute value)

Significant figures? In most cases it is __________ to obtain the exact value for a measurement. We need to _____________ the significant figures - the meaningful digits in a measured or calculated quantity. The trick is _______ _____________________!

Significant Figures Rules for determining sig. figs.: 1.All non-zero #’s are sig. 2. Zeros between non-zeros are sig. (a zero sandwich!) 3. Zeros to the left of the first non-zero # are not sig. -> ______ -> _______ -> ______

Significant Figures Rules 4. Zeros at the end of a number and to the right of a decimal are sig. They are holding a place! 5.For #’s w/out decimals, the trailing zero may or may not be sig. We use Sci. notation on these. -> ______

1,000,000 years – now 1,000, years ?? Which zeros are important? Use scientific notation: Could be _________ or ________ or ____________, etc.

Significant Figures Determine the sig figs & Rule #: cm m g 7000 kg -> _____________ -> ______________ -> _______________ _________________

Scientific Notation Examples 1.Distance to Sun: 93,000,000 miles-> _______ miles 2. Vacuum pressure: torr->_______ torr

Sci. Not. w/ Calculators Example: 4 x x5 x = ? ActionDisplay Enter “4”4 Press “EE”4 00 Enter “23”4 23 Press “x“4 23 Enter “5”5 Press “EE”5 00 Enter “-12”5 -12 Press “=“2 12 (2 x )

Significant Figures Rules for adding and subtracting: Answer cannot have more digits to the right of decimal point than the original!! ____ round off

Significant Figures Rules for multiplying and dividing: Answer cannot have more significant figures than the original! 2.82 s.f. x s.f ___ round off

Significant Figures Report with the correct # of sig. fig.: 11,254.1 g g L – 3.13 L 8.16 m x m kg / 88.3 ml -> ______ g -> _______ L -> ____m;__ sf. -> _________ kg/ml; ___ s.f.

Measurements? Chemists make measurements to study the properties of matter. To keep things consistent, we all work in SI Units and use significant figures. We also make many conversions between different types of _________ ________. We also make many ________________

Derived Units Mathematical combinations of units Examples are:

Density? Density is a common physical property that relates the mass and volume of a substance: Density = Units: grams/mls or grams/cm 3

Density Example What is the density of a substance that has a mass of 84.7 g and a volume 55.4 cm 3. Density = mass/volume g = _____ g/cm 3 cm 3

g cm 3 = ___ cm 3 g Density Example What is the volume of a substance that has a density of 1.73 g/cm3 and a mass of 7.75 g. Density is a conversion factor g = 1.00 cm 3 or 1.00 cm 3 = 1.73 g

Matter? Matter is anything that occupies space and has mass. Chemistry is the study of matter and how it changes

Volume - _____________ (even air !) measured in ml and cm 3 Matter Mass - measure of amount of matter. Unit in grams (g)

Any substance that has a definite composition Chemical Examples:

The smallest unit of an Element that _____________ Properties of that element Atom

Classification of Matter

Elements _____ be separated into simpler substances by chemical means. Example:  Smallest part is an ______ Elements/Compounds Compounds are composed of atoms of _________ elements. Examples:

Phases of Matter There are three common phases of matter: ____ – closely spaced and _____ ____ – closely spaced but _____ ____ – large separation; mostly _____________

3 States of Water

PhaseAtom Movement ShapeVolumeEnergy Solid Liquid Gas

Properties An ________ property _______ on __________ matter is being considered. Example: An _________ property _______ depend on __________ matter there is.

Properties? In Chemistry we study of matter and how it changes; we need to be able accurately observe properties to do this!

Properties A __________ property is a characteristic that can be observed or measured _______ changing the identity of the substance. Examples include

A _________ property is a characteristic that describes the _______ of a substance to undergo changes that alter its identity. Examples include the _____ of coal ______ and the _____ of iron _______. Properties

A _______ change is when a substance changes physical condition but ________ involve a change in composition. A _______ change is when a substance changes a substance ______________________ of substances.

Properties Classify each of the following as either a physical change or a chemical change: Tearing a sheet of paper Melting a piece of wax Burning a log Milk turns sour -

Mixtures contain two or more substances and generally can be __________________. Pure substances have a _______ _____________ and distinct properties. Mixtures/Substances

Homogeneous means the ______ throughout. ________ separate by filtering. Mixtures Heterogeneous means that it is ___________. ____ separate by filtering