Problem 25
A Toyota Prius hybrid gets 23 kilometers per liter in city driving. What is the mileage in miles per gallon? (Given: \(1 \mathrm{~km}=0.621 \mathrm{mi}\) and \(1 \mathrm{~L}=0.264 \mathrm{gal})\)
Problem 26
A Toyota Prius hybrid gets 21 kilometers per liter in highway driving. What is the mileage in miles per gallon? (Given: \(1 \mathrm{~km}=0.621 \mathrm{mi}\) and \(1 \mathrm{~L}=0.264 \mathrm{gal})\).
Problem 27
A sterling silver spoon has a mass of \(65.5 \mathrm{~g}\) and contains \(7.50 \%\) copper. Find the mass of copper in the spoon.
Problem 28
A stainless steel spoon has a mass of \(55.5 \mathrm{~g}\) and contains \(10.5 \%\) chromium. Find the mass of chromium in the spoon.
Problem 29
If a solution contains \(255 \mathrm{~mL}\) of ethanol and \(375 \mathrm{~mL}\) of water, what is the percent of ethanol in the solution?
Problem 30
If 20.0 gallons of gasohol contains 2.40 gal of ethanol, what is the percent of alcohol in the gasohol?
Problem 31
If a solution contains \(255 \mathrm{~mL}\) of ethanol and \(375 \mathrm{~mL}\) of water, what is the percent of ethanol in the solution?
Problem 32
Sodium chloride, table salt, is composed of \(39.3 \%\) sodium and \(60.7 \%\) chlorine. Calculate the mass of sodium in \(0.375 \mathrm{~g}\) of salt.
Problem 33
Before 1982 the U.S. Mint cast penny coins from a copper and zinc mixture. If a 1980 penny weighs \(3.051 \mathrm{~g}\) and contains \(0.153 \mathrm{~g}\) zinc, what is the percent of copper in the coin?
Problem 34
In 1982 the U.S. Mint stopped making copper pennies and began phasing in pennies made of zinc plated with a thin layer of copper. If a 1990 penny weighs \(2.554 \mathrm{~g}\) and contains \(2.490 \mathrm{~g}\) zinc, what is the percent of copper in the coin?
