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1. If a sample of strontium nitrite contains 45 g of oxygen, how many grams of strontium does it contain? Give your answer in correct standard notation. 2. How many moles of atoms are in a 12.8 kg sample of cadmium borate? Give your answer in correct scientific notation.  3. How many grams oxygen are in 6.89 g of arsenic acid? Give the answer in standard notation.  4. 9.894 g of a metal are reacted with oxygen to produce 14.4605 g M2O3. What is the metal?  5. What is the empirical formula of a compound with the following mass percent composition: 12.218% P, 16.865% S, and 70.917% Br?  6. What is the molecular formula of a compound whose molar mass is 360.50 g/mol and whose empirical formula is SiO2? 7. What is the percent mass composition of hydrogen in ammonium acetate? 8. How many grams of water would be needed to make a 0.56 M solution with 2.53 kg potassium phosphate? Assume the density of the solution is 1.23 g/mL. Give the answer in correct scientific notation. 9. What is the molarity of an acetic acid solution if its volume is 6.78 x 103 mL and it contains 9.60 x 1024 carbon atoms? Give the answer in standard notation. 10. If 923 mL of a 1.62 M solution of lithium sulfate is mixed with 0.0450 L of a 13.5 M solution of aluminum sulfate, what is the molar concentration of total ions in the final solution? Give the answer in standard notation.  11. What volume of water (in mL) must be added to 238 mL of 0.405 M hydrochloric acid to create a solution that with a pH of 0.681? Give the answer in standard notation. 12. What is the %(m/m) concentration of a 4.56 M solution of iron (III) bromide? Assume the density of the solution is 1.07 g/mL. Give the answer in standard notation. 15. Calculate the pH of the following solution that has 7.32 x 10^-10 M hydroxide ions. Calculate the hydronium ion concentration of a solution with a pOH of 12.8. Give the answer in scientific notation.  
 What is the pH of the resulting solution when 45.9 nL of a pH 5.60 solution is mixed with a 6893 pL of a pOH 8.10 solution?  
 18. A student makes a potassium bromide solution with 7.40 x 103 g water at 75oC. She then finds that she can still add an additional 345 kg of potassium bromide before no more will dissolve. What was the original molar concentration of the solution she made? Assume the density of the solution (at any concentration) is 1.21 g/mL. Give the answer in standard notation. Use the solubility chart from lecture notes. 19. A student makes a saturated solution of potassium nitrate at 85oC with 341 g water and then cools the solution down to 15oC. What mass (in g) of potassium nitrate will precipitate out of solution when he cools his solution down? Give the answer in standard notation. Use the solubility graph in the lecture notes.