HomeworkSolutionsChpt2

# HomeworkSolutionsChpt2 - Chapter 2 Homework Solutions km 65...

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1 Chapter 2 Homework Solutions 9. 65 mi 1h r × 1.6093 km 1m i = 104.6 km hr 1.0 × 10 2 km hr Keep in mind that the original information has only two significant figures, so the result of these multiplications and divisions must also have two significant figures. 12. 120 in 3 × 2.54 cm 1in × 2.54 cm × 2.54 cm = 120 in 3 × 2.54cm 3 = 2.0 × 10 3 cm 3 2.0 × 10 3 cm 3 × 1mL 1cm 3 × 1L 1000 mL = 2.0 L Notice: The conversion between liters and milliliters used here indicates a larger number (1000) of small things (mL) equal to a smaller number (1) of large things (L). Conversely, you can use the conversion relating a smaller number (10 –3 ) of larger things (L) to a larger number (1) of small things. 2.0 × 10 3 cm 3 × 3 × 10 3 L = 2.0 L 17. The symbols for the elements in this crystal are Ca (calcium) and F (fluorine). 2.83 g × 1kg 1000 g = 0.00283 kg 2.83 g × 1lb 453.59 g = 0.00624 lb 30. 280 mg Na × 1gNa 1000 mg Na = 0.28 g Na 0.28 g Na 30 g cereal × 100 % = 0.9 % Na in cereal 33. The element technetium has the symbol Tc. On the periodic table, we find it listed with the atomic number 43. So, the atom has 43 protons , 43 electrons and (99 – 43 =) 56 neutrons . 41. (a) The element beryllium has the symbol Be. On the periodic table, we find it listed with the atomic number 4. The given number of neutrons is 5. So, (4 + 5 =) 9 is the mass number for this beryllium atom. (b) The element titanium has the symbol Ti. On the periodic table, we find it listed with the atomic number 22. The given number of neutrons is 26. So, (22 + 26 =) 48 is the mass number for this titanium atom. (c) The element gallium has the symbol Ga. On the periodic table, we find it listed with the atomic number 31. The given number of neutrons is 39. So, (31 + 39 =) 70 is the mass number for this gallium atom.

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## This note was uploaded on 09/13/2008 for the course CHEM 1410 taught by Professor Acree during the Spring '08 term at North Texas.

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HomeworkSolutionsChpt2 - Chapter 2 Homework Solutions km 65...

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