A 1995 penny having a mass of 2.740 g is cut to expose the zinc and dropped into sulfuric acid. After the zinc has completely reacted (stops bubbling), the copper shell is found to have a mass of 0.055 g. Calculate (to the correct number of significant figures) the mass of zinc in the penny. Your Answer: Answer

A 1995 penny having a mass of 2.740 g is cut to expose the zinc and dropped into sulfuric acid. After the zinc has completely reacted (stops bubbling), the copper shell is found to have a mass of 0.055 g. Calculate (to the correct number of significant figures) the mass of zinc in the penny. Your Answer: Answer

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter1: The Nature Of Chemistry

Section: Chapter Questions

Problem 127QRT

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On October 21, 1982, the Bureau of the Mint changed the composition of pennies (see Exercise 120). Instead of an alloy of 95% Cu and 5% Zn by mass, a core of 99.2% Zn and 0.8% Cu with a thin shell of copper was adopted. The overall composition of the new penny was 97.6% Zn and 2.4% Cu by mass. Does this account for the difference in mass among die pennies in Exercise 120? Assume the volume of the individual metals that make up each penny can be added together to give the overall volume of the penny, and assume each penny is the same size. (Density of Cu = 8.96 g/cm3; density of Zn = 7.14 g/cm3).
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