1cm Sand Meter Stick BalanceSpring ScaleGraduated Cylinder Mass/Volume The SI system It is a group of units used by scientists to measure length, mass, volume, density, temperature and weight it is a decimal system Every conversion is by some power of 10. has two parts. A prefix and a base unit A prefix tells how many times to divide or to multiply by 10 Length (L) Mass (M) Weight (W) Volume (V) Density (D) Temperature (T) Thermometer International System Of Units

UNITS OF MEASUREMENT A.DEFINED UNITS B. DERIVED UNITS

S.I. Base Units DEFINED UNITS The International System of Units (S.I.) defines seven base units for the seven base quantities: Quantity Name Symbol lengthmeterm masskilogramkg timeseconds electric currentampereA thermodynamic temperaturekelvinK luminous intensitycandelacd amount of substancemolemol

Derived Units Commonly Used in Chemistry Derived Units: Derived Units: Units formed by combining base units QuantityNamesymbol AreaSquare meter m 2 SpeedMeter per secondm/s VolumeCubic meterm3m3 Mass densityKilogram per cubic meterKg/m³

Numbers in the metric system are made larger or smaller by adding prefixes to the base unit.  The Golden Ticket – B PrefixSymbolValueFactor petaP tetraT1,000,000,000, GigaG1,000,000, MegaM1,000, kilo-k1 000 (thousand)10 3 hecto-h100 (hundred)10 2 deca-da10 (ten)10 1 Base unit meterm110 0 deci-d0.1 (tenth)10 -1 centi-c0.01 (hundredth)10 -2 milli-m0.001 (thousandth)10 -3 micro(μ) nanon picop femtof0.000,000,000,000,

Grams Liters Meters Tera Giga Mega Kilo Hecto Deka (base units) Deci Centi Milli Micro Nano Pico Conversion x10 3 x10 3 x10 3 x10 3 Tetra Giga Mega kilo meter milli micro nano pico x x x x x x x To convert from LARGER to a SMALLER unit MULTIPLY. To convert a SMALLER unit to a LARGER unit DIVIDE In most cases the prefix is placed in front of the base unit to indicate the size of the unit. The kilogram is the only base unit which already has a prefix.

Length  The distance from one point to another  Meter – the SI unit of length  Larger objects (i.e. the room)  – meter stick  Smaller objects (i.e. pencil length)  – centimeter ruler Frequently used SI units Length 1 millimeter (mm) = 1000 micrometers (  m) 1 centimeter (cm) = 10 millimeters (mm) 1 meter (m) = 100 centimeters (cm) 1 kilometer (km) = 1000 meters (m)

Mass  The amount of matter in something  The SI unit for mass is the kilogram (kg)  It is measured by balance However, some measurements of mass like the mass of vitamins or medicines are so small that we use milligrams (mg) to measure their mass Frequently used SI units Mass 1 gram (g) = 1000 milligrams (mg) 1 kilogram (kg) = 1000 grams (g) Mass vs. Weight The mass of an object does not change. The weight of an object changes as a result of changes in gravity. Newton (N) - the basic unit of weight in the metric system.

Volume  The amount of space a substance takes up  The SI unit of volume is cubic meter (m) 3  length x width x height  it is the SI unit used to measure the unit of solid  Volume of a liquid is unit of volume for everyday use is the liter, a non-SI unit. found using a graduated cylinder Frequently used SI units Volume 1 milliliter (mL) = 1 cubic centimeter (cc) or (cm 3 ) 1 liter (L) = 1000 milliliters (mL) or 1 dm 3

Temperature a measure of how hot or cold something is  Kelvin is a unit of temperature in the SI system.  On the Kelvin scale, the freezing point of water is kelvins (K), and the boiling point is K.  On the Celsius scale, the freezing point of water is 0°C and the boiling point is 100°C.  The zero point on the Kelvin scale, 0 K, or absolute zero, is equal to  °C.  To convert from Celsius to Kelvin: A temperature of 30 degrees Celsius is equivalent to 243 K.300 K.303 K.247 K.

 Density = mass/volume (units are usually g/mL)  Mass= density x volume  Volume= mass/density The density of water = 1.00 g/mL The density of oil = 0.91 g/mL If, an object has a mass of 15 grams and occupies a volume of 5.0 cm 3 Its density is Density a measure of the amount of matter that occupies a certain volume SPECIFIC GRAVITY This is the ratio of the density of the mineral to the density of water. Specific gravity= density of substance/ density of water Sp.gr= d sub/ d water Area = length x width M²= m x m Most areas are measured in square (base) meters

Change:  1.5 kg to g  430g to mg  1350 g to kg  450 cm = _______m  3.2 km = _______ m  1.4 m = ________ mm  0.60 L to mL