HOME

Course Chapters

Calculator Fundamentals

Mathematics Review

Basic Concepts

Advanced Concepts


Section Tests

Pre-test

Post-test


Useful Materials

Glossary


Online Calculators

Redox Calculator

Kinetics Arrhenius Calculator

Thermodynamics Calculator

Nuclear Decay Calculator

Linear Least Squares Regression

Newton's Method Equation Solver

Compressibility Calculator

Units Conversion Calculator

Nomenclature Calculator


Related Information Links

Texas Instruments Calculators

Casio Calculators

Sharp Calculators

Hewlett Packard Calculators


Credits

Contact Webmaster


Another Problem 1

In an experiment, a chemist allows a red solution to flow at a rate of 0.1 mL per second for 14 seconds into a beaker containing a blue solution. The red solution has a density of 1.10 g/mL, and the blue solution has a density of 0.98 g/mL. Rounding each answer to the correct number of significant figures, if there are initially 20. mL of blue solution in the beaker:

(a)
How many grams of blue solution are in the beaker?
(b)
How many milliliters of red solution have been added after 14 seconds?
(c)
How many grams of red solution have been added after 14 seconds?
(d)
Recalculate the answers for (b) and (c) for a red flow rate of 0.10 mL per second.

Solutions:
(a)  20 g    (b) 1 mL   (c) 2 g   (d) 1.4 mL, 1.5 g


Sketch:

This is largely a problem of unit conversions and keeping track of significant figures. For a flow rate of 0.1 ml per second, there is only 1 significant figure for this measurement, so the answers that use this quantity are only good to 1 significant figure.

(a)
20 mL x .98 g/mL = 19.6 g, but to 2 sig figs, this is rounded to 20 g.
(b)
0.1 mL/s x 14 s = 1.4 mL, so to 1 sig fig this is rounded down to 1 mL.
(c)
0.1 mL/s x 14 s x 1.10 g/mL = 1.54 g, so to 1 sig fig this is rounded up to 2 g.
(d)
0.10 mL/s x 14 s = 1.4 mL, so to 2 sig fig this is 1.4 mL
0.10 mL/s x 14 s x 1.10 g/mL = 1.54 g, so to 2 sig fig this is rounded down to 1.5 g.

Try another problem like this one.

Next Try It Out Problem.


Developed by
The Shodor Education Foundation, Inc.
in cooperation with the Department of Chemistry,
Appalachian State University

Copyright © 1998
Last Update:
Please direct questions and comments about this page to
WebMaster@shodor.org