Chemistry Ch. 3

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Chapter 3

1. 1 atom of X = atomic mass (amu)
1 mole f X=atomic mass in grams
1 mole of something = 6.022 x 1023 units of that substance 1 mole of a compound =66.022 x 1023 atoms

6.022 x 1023 amu =1 g

2. What is the mass of 6 atoms of Fe?

Answer: 6 atoms of Fe x 55.85 amu÷atom of Fe x 1 g of Fe÷6.022 x 1023 amu =

3. How many atoms does it take to make 1 g of Gold (Au)?

Answer: 197.0 g Au =1 mole of Au

1 g of Au=? 1 mole of Au/197 g Au x 1 g of Au= 0.0051 or 5.10 x 10-3 moles of Au

1 mole of Au contains 6.022 x 1023 atoms of Au

5.10 x 10-3 moles of Au = 6.022 x 1023 atoms of Au/1 mole of Au x 5.10 x 10-3 moles of Au

= 3.06 x 1021 atoms of Au

4. Give the number of moles of each element present in in one mole of the following compounds.

a. Hg2I2 b. Hall c. Fe203

5. What is the mass of 4.28 x 1022 molecules of water?

6. What is molar mass of a. Ca2Fe(CN)6 12 H2O b. C10H16O3

7. How many grams of grams of Cobalt(Co) in 5.00 x 5.00x 1022

8. How many Carbon atoms are there in 1.00 x 10-6g of C2H5OH

9. Calculate the % C, H & O in C3H4O2

10. The characteristic odor of pineapple is due to Ethyl butanoate, a compound containing Carbon, Hydrogen, and Oxygen. Combustion of 2.780 g of ethyl butanoate leads to the formation of 6.32 g of CO2 and 2.58 g of H2O. If the molar mass of the compound is 100 and 150 g/mole, what is the molecular formula?

11. If 30.8 g of O2 are mixed with 30.8 g of H2 and ignited, what mass of water is produced?

12. Balance the following equations

a)CH4(g) + O2 (g)→ CO2(g) + H2O(l)

f) Al2(SO4)3(s) + Ca(OH)2 (aq) → Al(OH)3 (aq))+ CaSO4(s)

g) SO2 (g)+ Cl2 (g)→ SO2Cl2(g)

h) SO2Cl2 (g)+ H2O (l)→ H2SO4 (aq)+ HCl(aq)

i) H2SO4 (aq)+ Ca(OH)2 (aq)→ CaSO4(s) + H2O(l)

j) C2H5OH (l) +O2(g) → CO2(g) + H2O (l)

k) Zn(s) + HCl(aq) → ZnCl2(aq) + H2(g)

SHOW CLEARLY ALL YOUR CALCULATIONS STEP BY STEP, SHOW MOLAR MASS, MOLES, and GRAMS… ETC.

13. The Claus reactions, shown below, are used to generate elemental sulfur from hydrogen sulfide. Balance the equation & Show the net equation

H2S + O2 → SO2 + H2O

SO2 + H2S → S + H2O

14. When 189.4 g of ethylene (C2H4) burns in oxygen to give carbon dioxide and water, how many grams of CO2 are formed? Write a balanced equation first.

15. Phosphoric acid can be prepared by reaction of sulfuric acid with “phosphate rock” according to the equation: Ca3(PO4)2 (s) + 3H2SO4 (aq)→ 3CaSO4 (s)+ 2H3PO4 (aq)

Suppose the reaction in (4) is carried out starting with 105 g of Ca3(PO4)2 and 93.3 g of H2SO4. Which substance is the limiting reactant?

16. A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride: 2Li + F2 → 2LiF. After the reaction is complete, what will be present?

17. Naturally occurring iron contains 5.82% [pic], 91.66% [pic], 2.19% [pic], and 0.33%[pic]. The respective atomic masses are 53.940 amu, 55.935 amu, 56.935 amu, and 57.933 amu. Calculate the average atomic mass of iron.

18. If 30.8 g of O2 are mixed with 30.8 g of H2 and the mixture is ignited, what mass of water is produced? Write a balanced equation first.

19. Consider the following reaction:
[pic]

What mass of CCl4 will be formed if 1.20 moles of methane react with 1.28 moles of chlorine?

The percent yield is a ratio of the ____________ yield to the _____________ yield, multiplied by 100%.

20. 0.1156 g of a compound reacted with oxygen gives 0.1638 g CO2 and 0.1676 g of...
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