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b) Compound – a substance of definite composition of elements.

b) Compound – a substance of definite composition of elements. It can be decomposed into two or more simpler substances by simple chemical changes but not by physical means. Example: SMORES. 1 smore contains 2 graham crackers, 1 marshmallow , and 3 chocolates.

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b) Compound – a substance of definite composition of elements.

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  1. b) Compound – a substance of definite composition of elements. It can be decomposed into two or more simpler substances by simple chemical changes but not by physical means. Example: SMORES 1smorecontains 2 graham crackers, 1 marshmallow, and 3 chocolates Ratio of crackers to marshmallows to chocolates = 2:1:3 6 smores contain: graham crackers marshmallows chocolates 12 6 18

  2. 1smorecontains 2 graham crackers, 1 marshmallow, and 3 chocolates Ratio of crackers to marshmallows to chocolates = 2:1:3 49 graham crackers 23 marshmallows 69 chocolates 23 smores!

  3. Chapter 2 Measurements and Units 1. Metric System mass – gram, g (1 g = 0.0022 pounds) length – meter, m (1 m = 39.37 inches) volume – liter, L (1 L = 1.06 Quarts) temperature – Celcius or centigrade, oC Freezing point of water = 0oC Boiling point of water = 100oC Energy – calorie, cal 1 cal = energy required to change 1 g of water 1oC Time – second, s

  4. 2. Prefix pico p 10-12 = 0.000000000001(one-trillionth)

  5. centimeter (cm) 1cm = 0.01 m = 1/100 m millimeter (mm) 1 mm = 0.001 m = 1/1000 m milliliter (mL) = 0.001 L = 1/1000 L kilometer (km) 1 km = 1000 m kilogram (kg) 1 kg = 1000 g kilocalorie (kcal) 1 kcal = 1000 cal megabite (MB) 1MB = 1,000,000 bites gigabite (GB) 1 GB = 1,000,000,000 bites

  6. 1 c.c.

  7. 3. Accuracy and Precision Accuracy - the correctness of a measurement Precision – reproducibility of measurements.

  8. 4. Significant figures

  9. 4. Significant figures

  10. 1.345 significant figures 0.2300 significant figures 0.00230 23.400500

  11. 5. Exponential notation (scientific notation) = 2.3 x 107 23000000 2 significant figures 2.300 x 107 ? significant figures 0.000000230 = 2.30 x 10-7 ? ? 2.300 x 10-7

  12. Perfect units, exact numbers and inexact numbers An exact number is a number whose value has no uncertainty associated with it – a number that arises when you count items or when you define a unit. Exact numbers Perfect units Infinite significant figures. Infinite significant figures. 1 ft = 12 in 1 hr = 60 min 1 cm = 1/10 m ½, ¼, etc. The value of an inexact number has a degree of uncertainty. 1 kg = 2.205 lb Inexact number All measurements are inexact

  13. 3.8 3.75

  14. 6. Significant figure in arithmetic • a) addition and subtraction • 2.34 + 30.6081 2.34 + 30.6081 32.95 32.9481 b) Multiplication and division 1.32 x 4.011 = 5.29452 = 5.29 3 significant figures

  15. 6.3 x 0.000834 = 0.0053 2 significant figures 7. Conversion of units

  16. It is experimentally determined that 1 inch equals 2.54 centimeters, or 1 centimeter equals 0.394 inch.

  17. Example 1 Convert 2.00 inches to centimeters. Example 2 Convert 9.05 cm to inches. Factor-Label Method

  18. Example 3 6.82 cm = ? feet

  19. Example 4 How many milligrams are there in 4.00 pounds?

  20. 8. Density Density = mass/volume (g/mL) Figure 2.7 (a) The penny is less dense than the mercury it floats on. (b) Liquids that do not dissolve in one another and that have different densities float on one another, forming layers. b) a)

  21. Example 1 2.0 g of metal occupies 0.40 mL. What is the density? Example 2 Density = 2.0 pounds/quart = ? g/mL

  22. Specific Gravity – ratio of the density of a substance to that of water. density of water = 1.00 g /mL Example: Density of lead = 11.3 g/mL specific gravity of lead = 11.3 no unit

  23. 9. Temperature Figure 1.4 Change of 180oF = change of 100oC oF oC 212o 100o 100o 180o 0o 32o

  24. Change of 180oF = change of 100oC 100 5 Change of 1oF = change of = change of oC oC 180 9 9 Change of 1oC = = change of oF 5 Example: 50oF = ?oC oF oC 34o 1o 33o 0o 32o

  25. oF oC 100o 212o 32o 0o

  26. Absolute Temperature – Kelvin, K K = 273 + oC examples

  27. 10. Heat energy and specific heat Unit of heat energy – calorie (cal) 1 cal = heat needed to raise 1 g of water 1oC 1 kcal = 1000 cal 1 cal = 4.184 Joules (J) SI system Specific heat (SH) of a substance SH = amount of heat needed to raise 1 g of that substance 1oC heat absorbed cal SH= = m xDT Mass x change of T cal = SH x m xDT

  28. cal = SH x m xDT cal SH of water = 1.0 ( ) g . oC Example 1 : How much heat is needed to raise 30 g water from 20oC to 30oC?

  29. Example 2 122 cal of heat is added to 20 g of methanol at 15oC. What is the final temperature? SH of methanol = 0.61 cal/g . oC

  30. Example 3 What quantity of heat is required to raise the temperature of 50 mL of ethanol from 22.0oC to 25.0oC? The density of ethanol at this temperature is 0.80g/mL. The specific heat of ethanol is 0.59 cal/g oC.

  31. Substance in blood Typical range Calcium 8.5 – 10.5 mg/dL Sodium 3.10 – 3.33 mg/mL Potassium 137 - 200 mg/L Cholesterol 105 – 200 mg/dL Fasting glucose 70 – 110 mg/dL Total protein 6.0 – 8.0 g/dL

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