Assigned Exercises

1. A sample of 8.000 g of nitrogen can be combined with 9.143 g of oxygen to form nitric oxide gas (NO). What mass of oxygen would be required to convert the same sample of nitrogen to nitrogen dioxide (NO2) instead?Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.287E-15______g

2. Lithium has two stable isotopes, 6Li and 7Li. If a sample is composed of 20.0% of the lighter isotope (with the balance being 7Li), calculate the average molar mass of the sample.Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15______g/mol

3. Compute the number of electrons in a flake of pure gold valued at $0.38. Assume that the price of gold is $1626.0/troy oz. (1 troy oz = 31.1 g)Enter the correct numerical value to 2.0% precision. Express scientific notation like 4.29E-15_______electrons

4. An unknown element has two naturally occurring isotopes. Isotope 1 has a mass of 96.00 amu and an abundance of 41.20%. Isotope 2 has a mass of 98.00 amu. What is the atomic mass of the element?Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.287E-15______amu

5. The Greek mathematician Archimedes is credited with discovering how to verify the amount of pure gold in an irregularly shaped object (e.g., a crown) by placing it in water. How much water should be displaced by a pure gold object having a mass of 0.7800 kg? Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.287E-15_______cm3

6. How many atoms are contained in a block of aluminum metal measuring 3.0 mm x 8.0 mm x 11 mm? The density of aluminum is 2.7 g/cm3.Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.3E-15_________atoms

7. How many atoms are contained in a titanium sphere having a diameter of 12.0 mm? The density of titanium is 4.506 g/cm3.Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15________atoms

8. Calculate the volume of 7.90 mol of water. Assume that the density of water is 1.00 g/mL.Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15_______mL

9. How many carbon atoms are in a 1.44 carat diamond? 1 carat = 200 mg (exactly)Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15_______atoms

10. What is the mass of 1.35 mol of BCl3?Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15_______g

11. How many moles of water molecules are in 2.10 g of water?Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15________mol

12. How many copper atoms are in a cube of copper metal measuring 1.12 cm on each edge? The density of copper is 8.96 g/cm3.Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15_________atoms

13. Calculate the molar mass of C9H16O2.Enter the correct numerical value to 1.0% precision. Express scientific notation like 4.29E-15_______g/mol

14. Calculate the mass of 4.77 moles of helium gas in kg.Enter the correct numerical value with the appropriate number of significant figures. Express scientific notation like 4.29E-15_______kg