Metric System Podcast For Chemistry

Metric System In order to do well in Chemistry this year, you must be familiar with basic metric system units and prefixes. You must also be able to perform simple conversions. And you should have an idea of how the metric units compare to the everyday units used in the United States.

Length The basic unit for length in the metric system is the meter. A meter is 39.37 inches, or a bit more than a yard. It is a useful unit for measuring the length of objects such as rooms, boats, houses, playing fields, etc. The symbol for meter is m.

Length If you wish to measure larger or smaller things, it may be more convenient to use a prefixed unit of length. For large distances, like between two towns, the kilometer is used. A kilometer is 1000 meters. Kilo comes from the Greek word for thousand. The symbol for kilometer is km. A kilometer is a bit more than a half mile. For small objects, you might use centimeters or millimeters. A centimeter is 1/100th of a meter. Centi comes from the Latin word for hundred. The symbol for centimeter is cm. A millimeter is 1/1000th of a meter. Milli comes from the Latin word for thousand. The symbol for millimeter is mm. There are 2.54 cm in an inch. For very small objects, such as atoms or molecules, you might use nanometers. A nanometer is 1/1000000000th (billionth) of a meter. Nano comes from the Greek word for dwarf. The symbol for nanometer is nm. A nanometer is too small to picture.

Length 1 kilometer (km) = 1000 meters (m) 1 meter (m) = 100 centimeters (cm) 1 meter (m) = 1000 millimeters (mm) 1 meter (m) = 109 nanometers (nm)

Volume The basic unit for volume in the metric system is the liter. A liter is 33.8 ounces, or a little more than a quart. It is a useful unit for measuring the volume of drinks or gasoline or other fluids. The symbol for liter is L. For measuring smaller volumes the milliliter is convenient. A milliliter is 1/1000th of a liter. The symbol for milliliter is mL. A cc or cubic centimeter is equal to a milliliter.

Volume 1 Liter (L) = 1000 milliliters (mL) 1 milliliter (mL) = 1 cubic centimeter (cm3) or (cc)

Mass The basic unit for mass in the metric system is the gram. A gram is .0353 ounces, or the mass of 1 mL of water. It is a useful unit for measuring the mass of recipe ingredients and quantities of food. A candy bar is about 30 grams. The symbol for gram is g. For measuring larger objects the kilogram is convenient. A kilogram is 1000 grams. It is also about 2.2 pounds mass. The symbol for kilogram is kg. For measuring smaller objects the milligram is used. A milligram is 1/1000th of a gram. Medicines are often measured in milligrams. The symbol for milligram is mg.

Mass 1 kilogram (kg) = 1000 grams (g) 1 gram (g) = 1000 miligrams (mg) *Also know that 1 g of water has a volume of 1 mL or 1 cm3 Notice that this fact links the metric units for length, volume and mass

Metric Prefixes Must Know For Reference kilo 1 kx = 1000x centi 100 cx = 1x milli 1000 mx = 1x nano 109 nx = 1x *x = m or L or g For Reference Tera 1 Tx = 1012 x Giga 1 Gx = 109 x Mega 1 Mx = 106 x deci 10 dx = 1x micro 106 mx = 1x pico 1012 px = 1x

Conversions Conversions can be done easily utilizing the following steps: 1. Identify given quantity and units. 2. Identify desired units. 3. Make ratio of desired units to given units (desired/given) 4. Make equation as follows: _______desired units = given units X ratio of desired units/given units 5. Solve.

Conversions Example- How many milligrams are in 8.13 grams? 1. Given- 2. Desired- 3. Ratio- 4. 5. Solve!

Sometimes, two ratios are necessary. Conversions Sometimes, two ratios are necessary. Example- How many kilometers are there in 85,412 centimeters? 1. Given- 2. Desired- 3. Ratios- 4. 5. Solve!

Here are some more practice conversions. 1. How many liters are in 23,472 ml? 2. How many mg are in 32.1 kg? 3. How many nm are in .5 km?