Worksheet 1

1. If 200.0 g of zinc sulfide contains 134.2 g of zinc, how many grams of sulfur can be obtained from 1.18 kg of zinc sulfide?a. 388 g Sb. 79.2 g Sc. 158.4 g Sd. 196 g Se. 792 g S

2. If 200.0 g of zinc sulfide contains 65.8 g of sulfur, what mass of zinc in g is contained in 8.705 kg of zinc sulfide?

3. 79Se contains how many protons, electrons, and neutrons respectively?

4. Fill in the following table for stable species:

Symbol Protons Neutrons

Electrons

Group Name Period

Element Name

Mg

37

Noble Gas 2

35

(Difficult) 118

5. Suppose that the radioactive element Technetium (Tc, Z = 43) has three isotopes: 97Tc (21.72%, 96.95 amu), 98Tc (58.70%, 97.99 amu) and 99Tc (98.92 amu). What is the atomic mass of Tc as it would appear in the periodic table?

6. For each of the elements problem 5, predict the charge.

7. The mass of a proton in grams is 1.67E-24 grams (a very small number). Avagadro’s number is 6.02E23. What happens when you multiply the mass of the proton with the Avagadro’s number? What do you think the answer represents? Is it possible to measure 1.67E-24 grams on a laboratory balance?