## Atomic Conversions

1. The following lists the prefixes that are used in the metric system to describe the magnitude of a quantity. For example, a microliter is 1 x 10-6 liters.
1012 tetra T, 109 giga G, 106 mega M, 103 kilo k, 102 hecto h, 101 deka da, 10-1 deci d, 10-2 centi c, 10-3 milli m, 10-6 micro m, 10-9 nano n, 10-12 pico p, 10-15 femto f
1. Express the length of a wire that is 1.3 x 10-3 cm long in nanometers.
2. Express the weight of 1.00 ton of iron in kilograms.
3. Express 1.56 x 1012 kilojoules in gigajoules.
4. Express the length of a 1.8 Å bond (an Angstrom is 1 x 10-8 cm) in picometers.
2. Consider the following mass equivalencies:
1 gram = 15.4 grains, 1 gram = 0.035 oz, 1 pound = 453.6 grams
1. How many grains are there in an ounce?
2. How many ounces are there in a pound?
3. What is the weight of a grain in grams?
4. What is the weight of a grain in pounds?
3. A ream of paper is 500 sheets of paper. For a certain quality paper the average weight of one sheet is 9.22 g.
1. What is the weight expressed in pounds of one ream of paper?
2. An office uses 6.0 x 106 sheets of paper per year. How many reams should it buy?
3. A paper factory produces 10.0 tons of paper a day. How many reams does it produce annually?
4. A ream occupies 0.12 ft3. How much space is required to store 1.0 ton of paper (express the answer in ft3)?
4. The occupants of the planet Schaf eat the tiny, amazingly uniform seeds of the Birn tree. Each seed weighs 57 milligrams. The prodigious appetites of the Schafkins require that they eat several thousand seeds per day and therefore the seeds are packaged in units of 1000. Each of these packages is called a tat.
1. What is the mass of one tat?
2. The average Schafkin eats 15 tats at each of 5 meals per day. What is the weight of a 15 tat meal in grams and in pounds?
3. A tat factory produces 1.68 x 108 tats per week. How many Schafkins will this production feed each week (the Schaf week contains 10 days)?
4. The planet has a population of 3.23 x 109 Schafkins. How many factories must there be in order to feed all of the Schafkins?
5. What is the total weight of Birn seeds consumed by one Schafkin in one week?
5. Give the name of the elements with the following symbols:
1. Sn
2. Pb
3. P
6. Give the name, correctly spelled, of each of the following elements:
1. Cs__________________
2. Sn__________________
3. Ag__________________
4. Sb__________________
7. An aluminum atom has a diameter of about 3 Å (an Angstrom is 10-8 cm). How many aluminum atoms can be placed in a straight line 1.0 feet in length?
8. Mercury has a density of 13.5 g/mL Determine the number of moles of mercury in 1.0 L of mercury.
9. Suppose that Dalton had proposed that all atoms have the same size, weight, and other characteristics.
1. How many elements would there be?
0, 1, 2, none of these
2. How many compounds would there be?
0, 1, 2, none of these
10. Naturally-ocurring boron consists of two isotopes. One of them, 10B, is 19.6 % abundant. Calculate the atomic weight of the element.
11. How many atoms are there in 1.0 mL of mercury (density = 13.5 g/mL)?
12. If you could take one pound of aluminum and divide it into samples that contained one billion atoms each, how many samples would you have?
13. A compound contains 40.0 % carbon, 6.7 % hydrogen, and 53.3 % oxygen.
1. Calculate the empirical formula.
2. The compound has a molecular weight of 64. What is the molecular formula?
3. What is the weight of one molecule of the compound?
14. Consider the reaction below:
Zn + 2 HCl → ZnCl2 + H2
1. If 10 g Zn are mixed with 0.10 mole of HCl and the reaction goes to completion, how many grams of H2 will be formed?
2. How many moles of Zn (mixed with excess HCl) are required to form 0.50 g H2 if the yield is 20%?
15. What is the mass of 2.21 moles of phosphorus trichloride?
16. If there are 2.00 x 1024 atoms of Cl in a sample of CCl4, how many grams of CCl4 are present?
1. What is the density of CCl4 if this many grams occupy a volume of 20.0 mL?
17. The density of water (H2O) at 25°C is 9.970 x 102 kg/m3. How many hydrogen atoms are in 15 mL of water at this temperature?
18. One mole of hydrogen gas, H2, weighs __________ g.
19. 15.7 g of iron contains____________ atoms of iron.
20. One mole of alligators have ___________legs.
21. A sample of chloroform (CHCl3) weighing 150 g contains:
1. how many moles of CHCl3?
2. how many chloroform molecules?
3. what weight of carbon?
4. how many chlorine atoms?
5. how many moles of hydrogen?