Mathematics Of Atomic Theory

Chemistry Honors

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Mathematics of the Atomic Theory 1) Compound XY is known to contain 45.0% X by mass. What is the % composition for element Y? How much mass would Y have in a 20.00 g sample of compound XY?

2) A 50.0-g sample of sodium chloride is found to contain 19.50 g of Sodium. What is the percent composition of Sodium in this compound? How much Chlorine would you find in a 70.00 g sample of sodium chloride?

3) Compound AB is found to contain 30.00 grams of element A and 25.00 grams of element B. Calculate the mass ratio of B to A.

4) What is the mass ratio of Chlorine to Lithium in Lithium Chloride if the percent composition of Lithium is 16.5%?

5) H2O and H2O2 are different compounds made from the same two elements. How does the law of definite proportions support this? Explain.

6) Substances A & B react to form products C & D. What is the mass of C if A has a mass of 14.00 grams, D has a mass of 20.00 grams, and B has a mass of 12.00 grams? Which mathematical law are you putting to use in solving this problem? Briefly explain.

7) A student throws sodium metal into water where it bubbles and fizzes until it disappears. She later takes the complete mass of the fluid and finds that it is less than the combined mass of the water & sodium before the experiment. She attempts to explain this loss of mass by concluding that the sodium "disappeared". Explain, in detail, which mathematical law she has not considered; and explain what really happened during the experiment that led to the mass discrepancies she observed.

8) The Oxygen/Hydrogen mass ratio of H2O is about 8/1. For H2O2, it is about 16/1. a. What information about each compound is necessary in obtaining these ratios? Explain how you would use them mathematically from the information you suggest is needed.

b. Use the law of multiple proportions to explain in detail how the mass ratios of both compounds are supportive of the atomic theory when compared with one another.

9) A 16.00 g sample of methane (CH4) is found to contain 12.00 grams of carbon and 4.00 grams of Hydrogen. A 56.00g sample of Ethylene (C2H4) is found to contain 48.00 grams of Carbon and 8.00 grams of Hydrogen. Use this information to mathematically illustrate and explain the Law of Multiple Proportions. (How will the composition of two compounds made from the same two elements compare?)

10) In the table below, fill in the five main components of Dalton's Atomic Theory. In the second column, write the mathematical law from which it is most likely that Dalton drew his conclusion. In the third column, explain your reasoning. 5 statements of Dalton's Theory

Mathematical Law in support of Dalton's statement

Explanation.