Introduction to Chemistry

1. Introduction to Chemistry • Health and Medicine • Sanitation systems • Surgery with anesthesia • Vaccines and antibiotics • Gene therapy • Energy and the Environment • Fossil fuels • Solar energy • Nuclear energy

2. Introduction to Chemistry • Materials and Technology • Polymers, ceramics, liquid crystals • Room-temperature superconductors? • Molecular computing? • Food and Agriculture • Genetically modified crops • “Natural” pesticides • Specialized fertilizers

3. Introduction to Chemistry Macroscopic Microscopic

4. gold ingots liquid nitrogen silicon crystals Introduction to Chemistry Chemistry is the study of matter and the changes it undergoes. Matter is anything that occupies space and has mass. A substance is a form of matter that has a definite composition and distinct properties.

5. Introduction to Chemistry A mixture is a combination of two or more substances in which the substances retain their distinct identities. INSPIRING CREATIVE AND INNOVATIVE MINDS

6. soft drink, milk, solder cement, iron filings in sand Introduction to Chemistry • Homogenous mixture – composition of the mixture is the same throughout • Heterogeneous mixture – composition is not uniform throughout INSPIRING CREATIVE AND INNOVATIVE MINDS

7. magnet distillation Introduction to Chemistry Physical means can be used to separate a mixture into its pure components. INSPIRING CREATIVE AND INNOVATIVE MINDS

8. Introduction to Chemistry • An element is a substance that cannot be separated into simpler substances by chemicalmeans. • 114 elements have been identified • 82 elements occur naturally on Earth • gold, aluminum, lead, oxygen, carbon, sulfur INSPIRING CREATIVE AND INNOVATIVE MINDS

9. Introduction to Chemistry INSPIRING CREATIVE AND INNOVATIVE MINDS

10. lithium fluoride quartz dry ice – carbon dioxide Introduction to Chemistry A compound is a substance composed of atoms of two or more elements chemically united in fixed proportions. Compounds can only be separated into their pure components (elements) by chemical means. INSPIRING CREATIVE AND INNOVATIVE MINDS

11. Introduction to Chemistry . INSPIRING CREATIVE AND INNOVATIVE MINDS

12. Particle Theory of Matter : Matter is made up of very tiny discrete particles

13. Introduction to Chemistry A Comparison: The Three States of Matter INSPIRING CREATIVE AND INNOVATIVE MINDS

16. gas solid liquid Introduction to Chemistry The Three States of Matter: Effect of a Hot Poker on a Block of Ice INSPIRING CREATIVE AND INNOVATIVE MINDS

17. sugar dissolving in water ice melting hydrogen burns in air to form water Introduction to Chemistry Types of Changes A physical change does not alter the composition or identity of a substance. A chemical change alters the composition or identity of the substance(s) involved. INSPIRING CREATIVE AND INNOVATIVE MINDS

18. The Properties of Chemical Substance Physical properties are those that can be observed without changing the identity of the substance. • examples : color, density,mass, boiling point Chemical properties are properties that describe how a substance changes into a completely different substance. • examples : flammability and corrosion/oxidation resistance .

19. Extensive and Intensive Properties An extensive property of a material depends upon how much matter is being considered. • mass • length • volume An intensive property of a material does not depend upon how much matter is being considered. • density • temperature • color

20. Measurement in Chemistry

21. Measurement in Chemistry

22. weight = c x mass A 1 kg bar will weigh on earth, c = 1.0 1 kg on earth on moon, c ~ 0.1 0.1 kg on moon Matter - anything that occupies space and has mass • mass – measure of the quantity of matter • SI unit of mass is the kilogram (kg) • 1 kg = 1000 g = 1 x 103 g weight – force that gravity exerts on an object

23. 0F = x 0C + 32 9 5 Measurement in Chemistry A Comparison of Temperature Scales K = 0C + 273.15 273.15 K = 0 0C 373.15 K = 100 0C 32 0F = 0 0C 212 0F = 100 0C

24. EXAMPLES A person has fever of 102.5F. What is this temperature in C? (2) The temperature of the hottest place in California is 134F. What is this temperature reading in C? in kelvins?

25. Measurement in Chemistry Volume – SI derived unit for volume is cubic meter (m3) 1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m3 1 L = 1000 mL = 1000 cm3 = 1 dm3 1 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m3 1 mL = 1 cm3

26. mass density = volume m d = V Measurement in Chemistry Density – SI derived unit for density is kg/m3 1 g/cm3 = 1 g/mL = 1000 kg/m3 Measurement in Chemistry

27. Measurement in Chemistry

28. Measurement in Chemistry • Gold is a precious metal that is chemically unreactive. • It is used mainly in jewelery, dentistry, and electronic devices. • A piece of gold ingot with a mass of 301 g has a volume of • 15.6 cm3. Calculate the density of gold.

29. Measurement in Chemistry • Solution We are given the mass and volume and asked to calculate the density. Therefore, from Equation (1.1), we write

30. The density of mercury, the only metal that is a liquid at room temperature, is 13.6 g/mL. Calculate the mass of 5.50 mL of the liquid. Measurement in Chemistry

31. Measurement in Chemistry • Solution We are given the density and volume of a liquid and asked to calculate the mass of the liquid. • We rearrange Equation (1.1) to give

32. Exercise: Density A piece of quartz mineral was added into a graduated cylinder containing 51.2mL water. After adding a quartz, the water level was 65.7mL. The quartz piece weighed 38.4g. What was the density of the quartz

33. desired unit given unit Measurement in Chemistry Dimensional Analysis Method of Solving Problems • Determine which unit conversion factor(s) are needed • Carry units through calculation • If all units cancel except for the desired unit(s), then the problem was solved correctly. given unit x given quantity x conversion factor = desired quantity = desired unit

34. A person’s average daily intake of glucose (a form of sugar) is 0.0833 pound (lb). What is this mass in milligrams (mg)? (1 lb = 453.6 g.) Measurement in Chemistry

35. StrategyThe problem can be stated as ? mg = 0.0833 lb The relationship between pounds and grams is given in the problem. This relationship will enable conversion from pounds to grams. A metric conversion is then needed to convert grams to milligrams (1 mg = 1 × 10−3 g). Arrange the appropriate conversion factors so that pounds and grams cancel and the unit milligrams is obtained in your answer. Measurement in Chemistry

36. The sequence of conversions is Using the following conversion factors we obtain the answer in one step: Measurement in Chemistry

37. An average adult has 5.2 L of blood. What is the volume of blood in m3? Measurement in Chemistry

38. Strategy The problem can be stated as ? m3 = 5.2 L How many conversion factors are needed for this problem? Recall that 1 L = 1000 cm3 and 1 cm = 1 × 10−2 m. Measurement in Chemistry

39. SolutionWe need two conversion factors here: one to convert liters to cm3 and one to convert centimeters to meters: Because the second conversion factor deals with length (cm and m) and we want volume here, it must therefore be cubed to give This means that 1 cm3 = 1 × 10−6 m3. Measurement in Chemistry

40. Now we can write Check From the preceding conversion factors you can show that 1 L = 1 × 10−3 m3. Therefore, 5 L of blood would be equal to 5 × 10−3 m3, which is close to the answer. Measurement in Chemistry

41. Liquid nitrogen is obtained from liquefied air and is used to prepare frozen goods and in low-temperature research. The density of the liquid at its boiling point (−196°C or 77 K) is 0.808 g/cm3. Convert the density to units of kg/m3. Measurement in Chemistry liquid nitrogen

42. StrategyThe problem can be stated as ? kg/m3 = 0.808 g/cm3 Two separate conversions are required for this problem: Recall that 1 kg = 1000 g and 1 cm = 1 × 10−2 m. Measurement in Chemistry

43. Solutionwe saw that 1 cm3 = 1 ×10−6 m3. The conversion factors are Finally CheckBecause 1 m3 = 1 × 106 cm3, we would expect much more mass in 1 m3 than in 1 cm3. Therefore, the answer is reasonable.