2.6 Problem Solving Using Unit Conversion

2.6 Problem Solving Using Unit Conversion

• For two units that describe the same quantity, write a conversion factor.

• The daily value is 150 mcg.

• The gold jewelry contains a lot of gold.

• A liter of milk costs $1.65.

• 1000 kilo is a metric ton.

• An hour has 60 minutes.

• There are 7 days in a week.

• There is a can of Coke.

• There is a label on a bottle that tells you how much of a drug you can take per 1 mL.

• There is one yard.

• The daily value is 70.

• The weight of one kilogram is 2.20 lbs.

• A car goes 27 miles per gallon of gas.

• By mass, sterling silver is 93% silver.

• The acids can be identified by writing the equality and two conversion factors.

• The liter is 1.06 quarts.

• The store sells oranges for $1.29 per pound.

• 100 mL is contained in one deciliter.

• A ring has 75% gold by mass.

• The daily value is 3.5 g.

• The car traveled 26.0 km on 1 L of gasoline.

• The mass of Earth's crust is 28.2%.

• Change from one unit to another using conversion factors.

• The process of problem solving in chemistry often requires one or more conversion factors to be changed.
• The unit of the given and the unit of the needed are identified for the problem.
• Sample Problem 2.8 shows how the problem is set up with one or more conversion factors used to convert the given unit to the needed unit.

• Greg's doctor ordered a heart exam.
• The dosages of pharmaceuticals are based on body mass.

• To convert the given unit to the needed unit, you have to write a plan.

• The equalities and conversion factors are listed.

• To calculate the answer, set up the problem to cancel units.
• Write the given, 164 lbs, and use the conversion factor that has lbs in the bottom number to cancel lbs in the given.

• The needed unit is in the numerator.
• After all the other units have canceled out, the unit you want in the final answer is the one that remains.
• This is a way to make sure that the problem is set up correctly.

• The numerical answer is adjusted to give a final answer with the proper number of significant figures.

• The answers to numerical problems contain a number and a unit.

• A total of 2500 mL of boric acid antiseptic solution is prepared.

• One factor follows the other in setting up these problems.
• The calculations can be done without writing intermediate results once the problem is set up.

• The process is worth practicing until you understand unit cancelation, the steps on the calculator, and rounding off to give a final answer.
• When two or more conversion factors are required, the final answer will be based on getting a final calculator display and rounding off zeros to give the correct number of significant figures as shown in Sample Problem 2.9.

• Greg has been diagnosed with a disease.
• His doctor prescribes a small amount of the drug to be taken once a day.

• The given and needed quantities should be stated.

• To convert the given unit to the needed unit, you have to write a plan.

• The equalities and conversion factors are listed.

• To calculate the answer, set up the problem to cancel units.
• The metric factor can be used to cancel milligrams and the clinical factor can be used to get the number of tablets.

• There is a bottle of cough syrup.
• If four times a day is given, it is measured for a patient.

• A person with 16% body fat by mass exercises regularly.

• To convert the given unit to the needed unit, you have to write a plan.

• The equalities and conversion factors are listed.

• To calculate the answer, set up the problem to cancel units.

• 1.33 lbs of ground round is contained in a package.

• Change from one unit problem to another using conversion factors.

• 5000 mL is the volume of a cooler.

• A hummingbird has a mass.

• There is a balloon with a large volume.

• The daily value is 800.

• A glass of orange juice contains a lot of juice.

• The following conversions can be performed using metric and 2840 mg of sodium.

• A jar has olives.