Key 1.13 JDL

Key 1.13 JDL - need to convert the number to a value...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Key for Micro Exam 1 Question 13 –edited by JDL Question 13: The mass of a very small rock is 570. μg (micrograms). What is the mass expressed in pg? Answers: (a) 5700 (b) 5.70 x 10 -4 (c) 5.70 x 10 5 (d) 5.70 x 10 8 (e) 5.7 x 10 4 (f) 5.70 x 10 -16 This is a conversion that can be accomplished using dimensional analysis but it might be a little tricky due to the uncommon units. Perhaps the simplest way to solve the problem is to convert μg to g and then convert g to pg. You need to know that 10 6 μg = 1 g and 10 12 pg = 1 g. 570. μ g | 1 g | 10 12 pg = 570. x 10 6 pg = 5.70 x 10 8 pg | 10 6 μg | 1 g After converting to pg, you’ll have to write your answer in scientific notation. That is, you’ll
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: need to convert the number to a value between 1 and 10. To do this, just move the decimal two places to the left and add a two to the exponent. Its important that you note the number of significant digits given in the question as well as the answer choices. Since there is a decimal point after the 0, there are three significant digits in the given data and therefore there must be three in the answer as well. Note however that in this class, unless you are told to consider the number of significant digits in choosing your answer, you should not let that be the deciding factor in your choice....
View Full Document

This document was uploaded on 11/04/2011 for the course CHEM 105 at BYU.

Ask a homework question - tutors are online