1. Matter, Measurement, and Problem Solving Units, Scientific Notation and Density

2. Units of Measurement Unit ◦ Standard quantity used to specify measurement ◦ Each measurement MUST have a unit!!

3. Systems of Measurement English Units Used in United States Inches, feet, Fahrenheit, etc. Metric System Used in most of the rest of the world Celsius, meters, liters, etc. International System of Units (SI units) System used by scientists Based on metric Kelvin, kilogram, meter

5. Comparison of Units

6. Temperature Scales °F=9/5°C + 32 K=°C + 273

7. Temperature Scale Practice The normal body temperature is considered to be 98.6 °F. What is this in Celsius?

8. Temperature Scale Practice You turn the stove to 425°F. What is this in Kelvin?

9. Prefixes- must memorize!!!!

10. Scientific Notation Able to express very large and very small numbers easier and more compact Written as:

11. Scientific Notation Practice 61,500 0.0000568 321 64,960,000 0.07085 1.09 x 10 3 4.22715 x 10 8 3.078 x 10 -4 9.004 x 10 -2

12. Base vs. Derived Units Derived is combination of base units Example: Volume= length x width x height 5 cm 5 cm x 5 cm x 5 cm = 125 cm 3 Same as 125 mL

13. Density Intensive property Extensive properties Density measures the compactness of a substance. As the density increases, the more mass it has in a given volume. As density increases, the volume of a given mass decreases Gases have very low density in comparison to solids and liquids

14. Density Practice What is the density of CO gas if 0.196 g occupies a volume of 100 ml?

15. Density Practice A block of wood 3 cm on each side has a mass of 27 g. What is the density of the block?

16. Density Practice An irregularly shaped stone was lowered into a graduated cylinder holding a volume of water equal to 2 ml. The height of the water rose to 7 ml. If the mass of the stone was 25 g, what was its density?

17. Density Practice Under certain conditions, oxygen gas (O 2 ) has a density of 0.00134 g/mL. Find the volume occupied by 250.0 g of O 2 under the same conditions

18. Specific Gravity Relative density Comparison of two densities in the same units and same conditions ◦ Therefore units cancel Used regularly in various fields… ◦ Determine buoyancy ◦ Construction- soil compressive strength