Chme(Mastring-Ch1)

# Chme(Mastring-Ch1) - Dimensional Analysis Learning Goal To...

This preview shows pages 1–6. Sign up to view the full content.

Dimensional Analysis Learning Goal: To understand how to use dimensional analysis to solve problems. Dimensional analysis is a useful tool for solving problems that involve unit conversions. By carefully tracking units and conversion factors, you can avoid many of the errors commonly encountered in chemistry problems. Dimensional analysis can also help you work through problems when you are not sure where to begin. Dimensional analysis involves multiplying a given value by a conversion factor. This results in a value in the new units. The conversion factor can be the ratio of any two quantities, as long as the ratio is equal to one. For example, dimensional analysis could be used to determine the number of nickels in 3432.35 . To begin, write down the starting value, 3432.35 . This can also be written as a fraction: . Next, convert dollars to cents. This conversion involves a simple conversion factor: . Note that the "dollar" unit should appear on the bottom of this conversion factor, since "dollars" appears on the top of the starting value. Finally, convert cents to nickels. This conversion also involves a simple conversion factor: . This time "cents" should be on the bottom of the conversion factor, since it was on top of the previous conversion factor. Combining these expressions gives us Finally, cancel units. Since dollars are divided by dollars, and cents are divided by cents, both of these units can be canceled. Multiplying through gives the final result: You wash dishes for a chemistry laboratory to make extra money for laundry. You earn 6 , and each shift lasts 75 . Your laundry requires 6 .

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Part A How many shifts must you work if you wish to wash 10 of laundry? Hint A.1 How to approac h the problem Hint not displaye d Hint A.2 Find the number of quarters require d Hint not displaye d Hint A.3 Find the number of dollars require d Hint not displaye d
Scientific Notation Scientific notation can be used to express very large or very small numbers more easily. For example, In MasteringChemistry, you may enter answers in scientific notation in the following format: 2.998*10^8 5.09*10^-6

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Part A Convert the number 0.000127 to scientific notation, then enter the answer using the Masterin gChemis try format . Express your answer numerica lly. ANSWER: 1 . 2 7 × 1 0 4 C o r r e c t Entering scientific notation on a calculator It is important, especially for exams, that you be able to enter scientific notation in your calculator. All calculators are different, but look for a button such as E , EE , or EXP . If this button exists on your calculator,
it means "times ten to the" and so you never actually type the number 10 . For example, would be entered on a calculator as 2.998 E 8 For entering negative exponents, some calculators require the sign to be entered after the exponent. For example, might be entered on a calculator as 5.09 E -6 or as 5.09 E 6- Also note that many calculators have a "change sign" button ( +/- ) that should be used for exponents instead of the button that indicates subtraction.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern