SB_Chem6A_08_Lecture3

SB_Chem6A_08_Lecture3 - The figures below represent...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemistry 6A The figures below represent examples of matter and its composition. Which statement describing these figures is INCORRECT? (a) (i) and (v) represent pure elements. (b) Only (iv) represents a pure compound. (c) Only (iii) represents a mixture of an element and a compound. (d) No figure represents a mixture of pure elements. (e) (iii) can be separated into (i) and (iv) by means of physical techniques. 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chemistry 6A The radioactive isotope 14 C has how many electrons, neutrons, and protons? (a) electrons = 6, neutrons = 6, protons = 8 (b) electrons = 8, neutrons = 6, protons = 6 (c) electrons = 8, neutrons = 8, protons = 6 (d) electrons = 6, neutrons = 8, protons = 6 (e) None of the above 2
Background image of page 2
Chemistry 6A 3 “The Periodic Table” Animation by Thomas Poon (Claremont McKenna College) set to Tom Lehrer’s “The Elements” (1995)
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chemistry 6A How Many Elements Occur Naturally? There are 111 authenticated elements, of which 88 are naturally occurring , with uranium being the element of highest atomic number (Z = 92). Despite the fact that all nuclides with Z >/= 83 are radioactive, uranium is naturally occurring because it has 2 isotopes ( 235 U and 238 U) with half-lives (700 million years and 4.5 billion years, respectively) that are on the order of the Earth’s age. Elements 43 (Tc) , 61 (Pm) , 85 (At) and 87 (Fr) have no stable isotopes, and none of long half-life, so they are not naturally present. These “ synthetic elements ” are only known on Earth as the product of nuclear reactors or particle accelerators; or as byproducts from nuclear explosions. 4
Background image of page 4
Chemistry 6A … And other Elemental Points! And elements 112, 113, 114, 115, 116 and 118 have not been granted official status by IUPAC. October 16, 2006: Experiments reported that 3 atoms of element 118 (t 1/2 = 0.89 msec) had been produced. In 2001 , the earlier claims of Uuo were retracted. Element 117 has not been observed! Not all elements occur in the “Free” state! In the early 1800s Sir Humphrey Davies pioneered the use of electricity from the Voltaic pile to decompose the salts of alkali metals. Many other elements have been isolated from mineral deposits. Emission spectroscopy helped to identify many elements! For example, He was discovered by astronomers as an emission line from the sun 30 years before it was found on Earth. 5
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chemistry 6A Elements at the Earth ʼ s Surface* Oxygen 49 Silicon 26 Aluminum 7.5 Iron 4.7 Calcium 3.4 Sodium 2.6 Potassium 2.4 Magnesium 1.9 Hydrogen 0.88 Titanium 0.58 Chlorine 0.19 Others 0.56 % by mass * includes oceans and atmosphere • Crust oxides include SiO 2 , Al 2 O 3 , CaO, MgO, Na 2 O, FeO, K 2 O, Fe 2 O 3 6
Background image of page 6
Chemistry 6A Elements in the Human Body Oxygen 65 Carbon 18 Hydrogen 10 Nitrogen 3 Calcium 1.5 Phosphorus 1.0 Potassium 0.35 Sulfur 0.25 Sodium 0.15 Magnesium 0.05 Cu, Zn, Se, Mo, F, Cl, I, Mn, Co, Fe 0.70 Li, Sr, Al, Si, Pb, V, As, Br Trace % by mass • Most of the body is made up of H 2 O • Carbon is the basic building unit for organic molecules 7
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 12/07/2009 for the course CHEM CHEM 6A taught by Professor Czarkowski during the Fall '07 term at UCSD.

Page1 / 40

SB_Chem6A_08_Lecture3 - The figures below represent...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online