Therefore: volume = mass / Density = (5.0 g) / (1.06 g/mL) QUESTION: Glacial acetic acid is a liquid with a density of 1.06 g/mL. If an experiment calls for 5.0 g of acetic acid, what volume of glacial acetic acid do we need? A. 4.7 mL, B. 4.72 mL C. 0.21 mL, D. 0.212 mL Density is defined as the ratio of mass to volume: Density = mass / volume Therefore: volume = mass / Density = (5.0 g) / (1.06 g/mL) = 4.71698 mL  4.7 mL Glacial acetic acid is a liquid with a density of 1.06 g/mL. If an experiment calls for 5.0 g of acetic acid, what volume of glacial acetic acid do we need? A. 4.7 mL, B. 4.72 mL C. 0.21 mL, D. 0.212 mL PAUSE CLICK Density is defined as the ratio of mass to volume. Therefore, to calculate density, we simply divide the mass by the volume. If we know the mass and density of a sample, we can calculate its volume by simply rearranging this equation. CLICK Volume equals HIGHLIGHT in yellow “mass” by the density HIGHLIGHT in green “density” The question gives us a mass of 5.0 grams HIGHLIGHT in yellow “5.0 g” and a density of 1.06 grams per milliliter HIGHLIGHT In green “1.06 g/mL” which is equal to 4.71698 milliliters. Note that the gram units cancel out. SHOW CANCELLATION OF UNITS. THere are 2 significant digits in 5.0 grams, and 3 significant digits in 1.06 g/mL CALLOUT The less precise term, 5.0 g has only 3 significant digits. Therefore, we express our answer to only 2 significant digits. We round off our answer to 4.7 mL The correct answer is A. This is a typical calculation you will encounter in the laboratory when dealing with corrosive liquids. It is not advisable to weigh corrosive liquids because they can ruin a balance, which is very expensive, if you happen to spill them. CLICK PAUSE END RECORDING

Video ID: 1A-8-1 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08