International System of Units 3.2

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International System of Units 3.2

Measuring with SI Units
3.2 Measuring with SI Units Bell Work Which five SI base units do chemists commonly use?

Measuring with SI Units
3.2 Measuring with SI Units The five SI base units commonly used by chemists are the meter, the kilogram, the kelvin, the second, and the mole.

3.2 Units and Quantities Units of Length Meter

3.2 Units and Quantities Common metric units of length include the centimeter, meter, and kilometer.

Solid object: cubic meter (m)3 Liquid: Liter (L)
3.2 Units and Quantities Units of Volume Solid object: cubic meter (m)3 Liquid: Liter (L) (10 cm  10 cm  10 cm = 1000 cm3 = 1 L). Or 1 mL = 1 cm3

3.2 Units and Quantities Common metric units of volume include the liter, milliliter, cubic centimeter, and microliter.

3.2 Units and Quantities Units of Mass Kilogram A gram (g) is 1/1000 of a kilogram; the mass of 1 cm3 of water at 4°C is 1 g.

3.2 Units and Quantities Common metric units of mass include kilogram, gram, milligram, and microgram.

Weight is a force that measures the pull on a given mass by gravity.
3.2 Units and Quantities Weight is a force that measures the pull on a given mass by gravity. The astronaut shown on the surface of the moon weighs one sixth of what he weighs on Earth. An astronaut’s weight on the moon is one sixth as much as it is on Earth. Earth exerts six times the force of gravity as the moon. Inferring How does the astronaut’s mass on the moon compare to his mass on Earth?

Temperature is a measure of how hot or cold an object is.
3.2 Units and Quantities Units of Temperature Temperature is a measure of how hot or cold an object is. Thermometers are used to measure temperature. Thermometers are used to measure temperature. a) A liquid-in-glass thermometer contains alcohol or mineral spirits. b) A dial thermometer contains a coiled bimetallic strip. c) A Galileo thermometer contains several glass bulbs that are calibrated to sink or float depending on the temperature. The Galileo thermometer shown uses the Fahrenheit scale, which sets the freezing point of water at 32°F and the boiling point of water at 212°F.

3.2 Units and Quantities Scientists commonly use two equivalent units of temperature, the degree Celsius and the kelvin.

3.2 Units and Quantities On the Celsius scale, the freezing point of water is 0°C and the boiling point is 100°C. On the Kelvin scale, the freezing point of water is kelvins (K), and the boiling point is K. The zero point on the Kelvin scale, 0 K, or absolute zero, is equal to  °C.

3.2 Units and Quantities Because one degree on the Celsius scale is equivalent to one kelvin on the Kelvin scale, converting from one temperature to another is easy. You simply add or subtract 273, as shown in the following equations.

3.4

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for Sample Problem 3.4 Problem Solving 3.17 Solve Problem 17 with the help of an interactive guided tutorial.

Energy is the capacity to do work or to produce heat.
3.2 Units and Quantities Units of Energy Energy is the capacity to do work or to produce heat. The joule and the calorie are common units of energy.

The joule (J) is the SI unit of energy.
3.2 Units and Quantities The joule (J) is the SI unit of energy. One calorie (cal) is the quantity of heat that raises the temperature of 1 g of pure water by 1°C.

3.2 Section Quiz. 3.2.

3.2 Section Quiz. 1. Which of the following is not a base SI unit?
meter gram second mole

3.2 Section Quiz. 2. If you measured both the mass and weight of an object on Earth and on the moon, you would find that both the mass and the weight do not change. both the mass and the weight change. the mass remains the same, but the weight changes. the mass changes, but the weight remains the same.

3.2 Section Quiz. 3. A temperature of 30 degrees Celsius is equivalent to 303 K. 300 K. 243 K. 247 K.

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