Vocabulary- Ch. 2, Sec. 2 Units of Measurement Measurement: dimensions, quantity, or capacity as ascertained by _______________ _________; they represent _____________. Quantity: something that has ________, ___, or ___________ Measurement and quantity are _____ the same. Example: the quantity represented by a liter is ______, the liter itself is _____________________.

Standard Measurement Nearly every measurement is a number plus a unit Note: Is is going to be very helpful if you train yourself to keep up with numbers and units in calculations. There has to be an agreement on measurement standards so comparisons can be made. Mention distances in foot lengths

“SI” Measurement Le Systeme International d’Unites Adopted in 1960 French Adopted in 1960 Has seven base units with other units ____________ from these seven Are standard measurements Often called ___________but there are actually some differences.

SI Base Units- page 34 Length meter m Mass kilogram kg Time second s Quantity Unit name Unit abbreviation Length meter m Mass kilogram kg Time second s Temperature kelvin K Amount of substance mole mol Electric current ampere A Light intensity candela cd

Metric Prefixes – p. 35 The following table lists the common prefixes used in the metric system (Know Them!):

Derived SI Units (page 36) Volume: _________________________ _____________ V = l x w x h (gives us cubic distance) The derived SI unit of volume is __ (___ is often used in chemistry) A non-SI unit of volume is the ______, L (smaller non-SI unit of volume is the mL) _____________

Density Density: _______________________ _____________________ D = m/V Units are expressed as _____, ____, ___ or _______(or any other mass/volume units)

More about Density Density is a characteristic _______ property It is an ______________property Can be used to help identify a substance See the table on page 38 Density Problems Worked in Class

Conversion Factors A conversion factor is a _______ derived from the _______ between two different units that can be used to _______ from one unit to the other They are equalities in _____________form. The following steps will help you use conversion factors for the rest of chemistry….they don’t ever go away!

Conversions An effective method for solving problems in science is the _________________. It is also often called _________________or the ____________________. There are three steps to solving problems using the unit analysis method. Read the problem and determine the unit required in the answer. Analyze the problem and determine the given value that is related to the answer. Write one or more unit factors to convert the unit in the given value to the unit in the answer.

More Practice Convert: 1.843 m to km 96.3 hg to g 0.0013 Mg to mg (two step problem, go to grams first, then to mg) 4863 µL to L 1.4 x 105 g to µg