1. International System of Units  Units provide a scale on which to represent the results of a measurement

3. Measurements of Length  Length - Fundamental unit is the meter - Fundamental unit is the meter 1 meter = 39.37 inches 1 meter = 39.37 inches

4. Measurements of Volume  Volume - amount of 3-D space occupies by a substance - amount of 3-D space occupies by a substance - fundamental unit is meter 3 (m 3 ) - fundamental unit is meter 3 (m 3 ) 1 cm 3 = 1 ml 1 cm 3 = 1 ml

5. Items for measuring volume  Graduated cylinder- useful for dispensing approximate volumes  Buret- must be used when accuracy is important  Volumetric flask- contains a specified volume of liquid

7. Measuring Mass  Mass - quantity of matter in an object - quantity of matter in an object - fundamental unit is the kilogram - fundamental unit is the kilogram

8. Measuring Density Density = mass/ volume Derived unit- a unit obtained from more than one base unit. Density- is a characteristic property that depends only on the composition of a substance, not on the size of the sample. Pure substances have specific densities. The density of a substance generally decreases as its temperature increases. Water is an important exception

10. Density Problems 1.What is the density of a block of marble that occupies 310cm 3 and has a mass of 853g? 2.Diamond has a density of 3.26g/cm 3. What is the mass of a diamond that has a volume of 0.350cm 3 ? 3.What is the volume of a sample of liquid mercury that has a mass of 76.2g, given that the density of mercury is 13.6g/ml?

11. Measuring Specific Gravity Specific Gravity- a comparison of the density of a reference substance. Water is a common reference substance. -Can be determined with a hydrometer Specific Gravity = density of substance/ density of water - Has no units

12. Measuring Temperature Temperature- is related to the energy and motion of particles Temperature scales Celsius scale- based on the freezing and boiling points of water. Celsius scale- based on the freezing and boiling points of water. a. freezing point = 0 C a. freezing point = 0 C b. boiling point = 100 C b. boiling point = 100 C

13. Kelvin scale- The zero point on the Kelvin scale is absolute zero. The theoretical point at which all motion stops. One degree Kelvin equals one degree celsius K= C + 273 K= C + 273 C= K - 273 C= K - 273

15. Measuring Temperature Practice Problems 1.Normal human body temperature is 37 C. What is your temperature in Kelvin? 2.The boiling point of the element Argon is 87 K. What is the boiling point of argon in C?

16. Conversion Factors Conversion factor- a ration of eqvivalent measurements, such as 100cm / 1m The measurement in the numerator is equivalent to the measurement in the denominator. Conversion factors are exact quantities. Therefore, they have an unlimited number of significant figures.