Matter, Measurement, and Problem Solving

1. Matter, Measurement, and Problem Solving Chapter 1

2. Practice problems Tro 1.8-1.15, 1.37-1.42

3. Ionic compounds • Composed of ions held together by electrostatic attractions • Composed of metals bonded to nonmetals • Represented by empirical formulas

4. Covalent Compounds • Discrete molecules where atoms are joined by shared electron bonds or covalent bondsComposed of nonmetals bonded to nonmetalsRepresented by structural formulas

5. Metallic compounds • Composed of metals bonded to metals • Will see more in chem 142

6. Physical and Chemical Properties • A physical property is one that can be observed without changing the makeup of a substance. • Color, conductivity, density, melting point, boiling point, density, hardness, and solubility • Changes that occur when observing physical properties are called physical changes.

7. Physical and Chemical Properties • A chemical property describes a chemical change (chemical reaction) that a substance undergoes. • Rusting of iron and caramelization of sugar are chemical changes.

8. A sample of calcium (an electrically conducting white metal that is shiny, relatively soft, melts at 850oC, and boils at 1440oC) was placed into liquid water that was at 25oC. The calcium reacted slowly with the water to give bubbles of gaseous hydrogen and a solution of the substance calcium hydroxide. • What are the physical and chemical properties described above? Practice problems Tro – 1.16-1.17, 1.44-1.50

9. Intensive Properties • Do not depend on the amount of sample present. Extensive Properties • Depend on the amount of sample present.. Practice problem Tro – 1.97

11. Practice problems Tro – 1.53-1.59

12. Conversion Factors Practice problems Tro –1.83-1.90

13. Which will require greater stamina and endurance on your part, an utterly boring 1-hr lecture or an equally boring micro-century lecture?

14. Aerogel or “solid smoke” is a novel material that is made of silicon dioxide, like glass, but is a thousand times less dense than glass because it is extremely porous. Material scientists at NASA’s Jet Propulsion Laboratory created the lightest aerogel ever in 2002, with a density of 0.00011 lb/in3. The material was used for thermal insulation in the 2003 Mars Exploration Rover. If the maximum space for insulation in the spacecraft’s hull is 2510 cm3, what mass (in grams) will the aerogel insulation add to the spacecraft? Practice problems Tro – 1.91-1.95, 1.105, 1.111-119

15. Temperature Temperature

17. Convert 25oC to oF • Convert 25oF to oC. Practice problems Tro – 1.51-1.54

18. New Temperature Scales • In the Willard temperature scale, water freezes at 345oW and boils at 745oW. Convert 36oC to oW. Practice problems Tro – 1.98-1.100

19. If diamonds cost $12960/scruple, what is the cost of diamonds per cubic inch? • (density of diamond = 3.51 g/cm3, 5 ct = 0.7716 scruple, 1 ct = 0.20000 g)

20. The density of alcohol at 20oC is 0.79 g/mL. The density of benzene at the same temperature is 0.88 g/mL. How many liters of alcohol would you get if you bought a pound of alcohol?

21. Marvin is going on a cottage cheese diet. He will allow himself 1080 calories per day. If one pint of cottage cheese contains 180 calories, how many gallons of cottage cheese may Marvin consume in one week? • (1 qt = 2 pts, 1 gallon = 4 qt)

22. An ore bed in an open pit gold mine yields 0.035 oz of gold per ton of ore. The mine operates 20 hr/day and shows an average profit of $25000 per day. It costs $200.00/oz to extract the gold from the ore and gold is selling for $325.00/oz. If the ore trucks have a capacity of 85 tons, how many trips per hour must they make to achieve this level of productivity?

23. Harry’s dog eats 2.00 lb of dog food per day. Harry pays $18.00 for a 50.00 lb sack of dog food. How much does it cost to feed Harry’s dog for 12 years?