ChemCom Extra Credit Problem

For Oct 16 – Oct 25

(This is a chance to get an extra kick to your end of quarter grade)

You may complete up to three extra credit problems in a term.  Each extra credit problem that is done correctly will add two points to your final grade (this is 0.6 of a letter grade).  Extra credit problems must be completed and turned in to Mr. Konieczko  PRIOR TO THE NEXT PROBLEM BEING POSTED in order to get credit.  Once a new problem is posted, there will be NO CREDIT awarded for the previous problem.  Generally, the problem turn in time will be 2:30, or when I leave on the last day of the time given, above.

This week’s problem: We are about to enter the world of chemical equations and the law of conservation of matter.  A spin off of the law of conservation of matter is the law of definite proportions, which states that the elements in any given compound are in definite proportions by mass.  That is, the ratio of mass of each element to that of every other element in the compound is a constant.

Problem:  If 6.537 g of zinc reacts with exactly 7.0906 g of chlorine to form the only compound of chlorine and zinc, how much zinc will react with:

                 a. 14.18 g of chlorine?

                 b. 28.36 g of chlorine?

                 c. 100.0 g of chlorine?

Problem:  The reaction of 6.54 g of zinc and 3.20 g of oxygen produces 9.74 g of zinc oxide, the only compound of these two elements.

                 a. How much zinc oxide would be produced if 6.54 g of zinc and 5.00 g of oxygen are allowed to react?

                 b. What law enables us to answer this question? 

                 c. How much zinc would react with 1.00 g of oxygen?

Note: The quarter ends on November 8. There will only be one more extra credit problem posted between now and the end of the first quarter.