Chapter 1, Problem 1.101E

Several samples of methane gas, the primary component of natural gas, are decomposed into carbon and hydrogen. The masses of the carbon and hydrogen are then weighed, and the results are tabulated as shown here. Which of these does not follow the law of constant composition? a. 4.0 grams hydrogen and 12.0 grams carbon b. 1.5 grams hydrogen and 4.5 grams carbon c. 7.0 grams hydrogen and 17.0 grams carbon d. 10 grams hydrogen and 30 grams carbon

Copper atoms. (a) What is the average mass of one copper atom? (b) Students in a college computer science class once sued the college because they were asked to calculate the cost of one atom and could not do it. But you are in a chemistry course, and you can do this. (See E. Felsenthal, Wall Street Journal, May 9, 1995.) If the cost of 2.0-mm diameter copper wire (99.9995% pure] is currently 41.70 for 7.0 g, what is the cost of one copper atom?

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).

Determine the mass in grams of 7.21 × 10²¹ atoms of carbon. (The mass of one mole of carbon is 12.01 g.)

Tin, element 50 on the periodic table, has 10 stable isotopes. 117^Sn makes up 7.687% of naturally occurring tin atoms. How many atoms of 117^Sn are present in 72.00 g of naturally occurring tin?

What is the mass, in grams, of exactly 230 sodium atoms? Would it be the same answer only in grams? 230 Na atoms x (1 mol/ 6.022 x 10^23 atoms) x (22.99 g Na/ 1 mol Na) = 8.78 x 10^-21 g Na I'm not sure if I set the calculation up right, but it gives me the same answer as the calculation for amu.

White phosphorus consists of a molecule made up of four phosphorus atoms. It burns in pure oxygen to produce tetraphosphorus decaoxide. A 1.00 g piece of phosphorus is burned in a flask filled with 2.60 x 1023 molecules of oxygen gas. What mass of tetraphosphorus decaoxide is produced?

Pitchblende is the most important compound of uranium. Mass analysis of an 84.2-g sample shows that it contains 71.4 g of uranium, with oxygen the only other element. How many grams of uranium are in 102 kg of pitchblende?

Determine the mass in grams of 3.11 × 10²¹ atoms of arsenic. (The mass of one mole of arsenic is 74.92 g.)