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Ch 6 Practice Test

Name _____________________

 

Calculate the formula mass for the following .

1. H2SO4 ________ 2. (NH4)3PO4___________ 3. Al(C2H3O2)3__________

 

Make the following conversions;

4. 5.84 g of sodium hydroxide to moles

5. 12.04 x 1024 atoms of mercury to grams of mercury

6. 4.75 moles of water to molecules of water

7. 116 grams of magnesium bromide to moles

8. 0.0263 moles of potassium nitrate to grams

9. 0.500 moles of oxygen gas to atoms of oxygen

10. 2.00 moles of nitrogen gas to grams

 

Determine the percent composition of each of the following.

11. MgBr2 12. Ca(NO3)2

 

13. Determine the empirical formula for substance that is 24.58% potassium, 34.81% manganese and 40.50 % oxygen.

 

14. Determine the empirical formula for a substance that is 56.4% phosphorus, and 43.7% oxygen.

 

15. If the molecular mass of the compound in problem # 14 is determined to be 220 AMU. , what is the molecular formula ?

 

 

 

Answers

1) 98.1 2) 149 3) 204 4) 0.146 5) 4.00 x 103 6) 2.86 X 1024

 

7) 0.630 8) 2.66 9) 6.02 X 1023 10) 56.0 11) 13.2% Mg, 86.8% Br

 

12) 24.4% Ca, 17.1% N, 58.5 % O 13) KMnO4 14) P2O3 15) P4O6