CHEM 1013C Fundamental Chemistry I

1. CHEM 1013C Fundamental Chemistry I Ch. 1 (cont.)

2. Homework 1 • Mercury is the only metal that is a liquid at room temperature. Its density is 13.6 g/mL. How many grams of mercury will occupy a volume of 95.8 mL? • Normally the human body can endure a temperature of 105oF for only short periods of time without damage to the brain and other vital organs. What is this temperature in oC? In K? • The medicinal thermometer commonly used in homes can be read to +/- 0.1oF, whereas those in the doctor’s office may be accurate to +/- 0.1oC. In degrees Celsius, express the percent error expected from each of these thermometers in measuring a person’s body temperature of 38.9oC. 1.30 x 103 g 40.6 oC, 314 K 0.1% for the F scale 0.3% for the C scale

3. Accuracy – how close a measurement is to the true value Precision – how close a set of measurements are to each other accurate & precise precise but not accurate not accurate & not precise

4. Factor-Label 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. The speed of sound in air is about 343 m/s. What is this speed in kilometres per hour?

5. 60 min m x x x 343 1 km 60 s s 1 hour 1 min 1000 m The speed of sound in air is about 343 m/s. What is this speed in kilometres per hour? meters to kilometres seconds to hours 1 km = 1000 m 1 hour = 60 min 1 min = 60 s

6. 60 min m x x x 343 1 km 60 s s 1 hour 1 min 1000 m The speed of sound in air is about 343 m/s. What is this speed in kilometres per hour? meters to kilometres seconds to hours 1 km = 1000 m 1 min = 60 s 1 hour = 60 min = 1.23 x 103 km/h Remember that conversion factors are considered “exact” numbers. Do not count them when determining significant figures for your answer.

7. Atoms, Molecules and Ions Chapter 2

8. Laws of chemical combination From experimental observations of many scientists in the 18th and early 19th centuries • Law of definite composition (Joseph Proust, 1799) • In a given chemical compound, the elements are always combined in the same proportion by mass. H2O will always contain 11.2% H and 88.8% O. • Law of conservation of mass • No detectable gain or loss of mass occurs in chemical reactions. Mass is conserved.

9. Law of definite composition

10. Dalton’s atomic theory (1808) Hypotheses about the nature of matter derived from the laws of conservation of mass and definite proportions • Elements are composed of minute, indivisible particles called atoms. • Atoms of the same element are alike in mass & size; atoms of different elements have different masses and sizes. • Compounds are formed by the union of 2 or more atoms of different elements. • Atoms combine to form compounds in simple numerical ratios (1:2, 2:3, & so on). • Atoms of 2 elements may combine in different ratios to form more than 1 compound. • A chemical reaction involves only the separation, combination, or rearrangement of atoms; it does not result in their creation or destruction.

11. Composition of compounds Dalton’s atomic theory led to the discovery of the law of multiple proportions • Law of conservation of mass • Chemical reactions do not create or destroy atoms; they simply separate, combine, or rearrange atoms. • Law of definite composition (Joseph Proust, 1799) • A compound always contains 2 or more elements combined in a definite proportion by mass. H2O will always contain 11.2% H and 88.8% O. • Law of multiple proportions • Atoms of 2 or more elements may combine in different ratios to produce more than 1 compound. CuCl & CuCl2, CH4 & C8H18,CO & CO2

12. Dalton’s model of the atom • Elements are composed of minute, indivisible particles called atoms. • Atoms of the same element are alike in mass & size; atoms of different elements have different masses and sizes. • Compounds are formed by the union of 2 or more atoms of different elements. • Atoms combine to form compounds in simple numerical ratios (1:2, 2:3, & so on). • Atoms of 2 elements may combine in different ratios to form more than 1 compound.

13. Dalton’s model of the atom Late 1800s/early 1900s: experiments show that atoms consist of subatomic particles • Elements are composed of minute, indivisible particles called atoms. • Atoms of the same element are alike in mass & size; atoms of different elements have different masses and sizes. • Compounds are formed by the union of 2 or more atoms of different elements. • Atoms combine to form compounds in simple numerical ratios (1:2, 2:3, & so on). • Atoms of 2 elements may combine in different ratios to form more than 1 compound.

14. Rutherford’s Model of the Atom atomic radius ~ 100 pm = 1 x 10-10 m nuclear radius ~ 5 x 10-3 pm = 5 x 10-15 m If the atom is the Houston Astrodome Then the nucleus is a marble on the 50 yard line 2.2

15. Model of the atom

16. Model of the atom • Subatomic particles: proton, neutron, and electron • Nucleus: dense core (red): protons and neutrons (nucleons) • Electrons surround nucleus and fill remaining volume of the atom

17. Subatomic Particles (Table 2.1) mass p = mass n = 1840 x mass e- 2.2

18. Subatomic particles • Almost all of the atomic mass is contributed by particles in the nucleus. • Mass of an e- is only about 1/1800 of that of a proton or a neutron. • Diameter of the atom is ~10,000 times the diameter of nucleus. • Almost all of the volume of an atom is occupied by electrons. • The number of protons equals the number of neutrons in an electrically neutral atom.

19. A X Mass Number Element Symbol Z Atomic Number 2 3 1 H (D) H (T) H 1 1 1 235 238 U U 92 92 Atomic number (Z) = number of protons in nucleus Mass number (A) = number of protons + number of neutrons = atomic number (Z) + number of neutrons Isotopes are atoms of the same element (X) with different numbers of neutrons in the nucleus 2.3

20. Dalton’s model of the atom • Elements are composed of minute, indivisible particles called atoms. • Atoms of the same element are alike in mass & size; atoms of different elements have different masses and sizes. • Compounds are formed by the union of 2 or more atoms of different elements. • Atoms combine to form compounds in simple numerical ratios (1:2, 2:3, & so on). • Atoms of 2 elements may combine in different ratios to form more than 1 compound.

21. Isotopes of hydrogen 2.3

22. Do You Understand Isotopes? 14 How many protons, neutrons, & electrons are in C? 6 6 protons, 8 (14 - 6) neutrons, 6 electrons How many protons, neutrons, & electrons are in C? 11 6 6 protons, 5 (11 - 6) neutrons, 6 electrons 2.3

23. The periodic table Chart that groups elements based on periodic regularities in chemical & physical properties You will learn much more about the periodic table in Ch. 8. 2.4

24. Noble Gas Halogen Alkaline Earth Metal Period Alkali Metal Group 2.4