ApchemWiki | RecentChanges | Preferences
Showing revision 6
Answer the following question in the space provided (do not have to show work)
1. What is the symbol for micro __________ , complete the blank _______ m = _________ nm
2. What is chemical name or chemical formula for:
- Potassium bisulfite ___________________
- HBrO3 ____________________
- Diphosphorus hexachloride ______________
- Sn(CO3)2 __________________
- Phosphoric acid ____________________
Answer the following problems (showing all work) on a separate sheet(s) of paper. One problem per side of page.
3. A 5.325g sample of methyl benzoate, a compound used in the manufacture of perfumes, is found to contain 3.758g of carbon, 0.316g of hydrogen, and 1.251g of oxygen. What is the empirical formula of this substance?
4. A strip of zinc metal weighing 2.00g is placed in an aqueous solution containing 2.50g of silver nitrate to form silver metal and zinc nitrate.
- Write the balanced chemical reaction including phases.
- How many grams of silver will be formed?
- If theoretically you should have gotten 1.85g of the metal, what is the percent yield for this reaction?
5. Water is added to 4.267 grams of UF6. The first products are 3.730 grams of a solid containing only uranium, oxygen and fluorine. The second product is a gas that was massed at 9.700 grams. The gas is 95.00 percent fluorine and the remainder is hydrogen.
- From the data, determine the empirical formula of the gas.
- What fraction of the fluorine of the original compound is in the solid and what fraction in the gas after the reaction?
- What is the formula of the solid product
- Write a balanced equation for the reaction between UF6 and H2. Assume that the empirical formula of the gas is the true formula.
6. The Space Shuttle environmental control system handles excess CO2 (which the astronauts breathe out - it is 4% by mass of exhaled air) by reacting it with lithium hydroxide, LiOH, pellets to form lithium caronate, Li2CO3 and water. If there are 7 astronauts on board the shuttle, each exhales 20.0 liters of air per minute, how long could clean air be generate if there were 2.50E4 g of of LiOH pellets available for each shuttle mission? Assume the density of air is 0.00100 g/ml.
Answers:
1. Go over in class
2. Go over in class
3.C4H4O
4. 1.59g Zn , 85.9%