Diemer_Sarah_Lab2

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Florida Atlantic University *

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1045 L

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Chemistry

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Apr 3, 2024

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docx

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Lab #2 . Density Your Name-Printed Please ______Sarah Diemer______________ Introduction Density is a measurement that is dependent on the material being tested but independent on the amount. It is a measure of the amount of material that occupies a certain volume. The denser a material the more a given volume of it will weigh. In general, gases are not dense in comparison to solids and liquids. Other than water, solids are denser than liquids. Materials : Measuring cup with any of the following units – ounces, quarts, cups, liters, or milliliters Balance or scales that weights in pounds, grams, kilograms, or ounces. Vegetable oil Nail Paper clip Styrofoam packing chip or part of an egg carton Piece of gravel Tooth pick Relative Density We can look at relative densities by comparing the results of the mass of a particular material in a given volume to one another. Often we will compare the relative densities to water by simply adding the material to water and noticing if the material sinks or floats for solids or for immiscible liquids (that is liquids that are not soluble in water) which liquid lays on the bottom or conversely on top.

To water contained in a transparent container such as a glass, add the following items and record if they sink or float for the solids or if they are the upper of lower layer for liquids. Also record if your observations are consistent with the material being denser than water by circling a “yes” in the appropriate column or if not denser than water by circling a “no”. Material Observation Denser than Water Vegetable oil _____ not denser_____________ Yes or No Nail _____denser_______________ Yes or No Paper clip _____not denser______________ _ Yes or No Styrofoam packing chip or part of an egg carton _________not denser__________ _ Yes or No Piece of gravel ____denser________________ Yes or No Tooth pick _________not denser___________ Yes or No Density Mathematically we define density, d, in terms of weight or mass, m, and volume, V as d = m / V We can rearrange this expression to determine mass if given density and volume using a mathematical operation called cross multiplication since the result of this cross multiplication is equal. This is shown below. d m 1 V = so that d V = m we can divide both sides by the same thing and not change the equality so we will divide d V = m by d to get d V = m d d = and V = d/m

Thus, we can solve for any of the three values given the other two values. Here, we will use a measuring cup to measure the volume of objects and a scale or balance to measure its weight. For regular objects such as cubes or rectangular objects we can obtain the volume through mathematical calculations. Thus the volume of a simple rectangular box is determined by simply multiplying the height by the length by the width of the box. For irregular objects we will employ an approach attributed to the ancient Greek mathematician Archimedes. Supposedly, Archimedes was given the task of determining if a new crown in the shape of a laurel wreath that had been made for King Hiero was solid gold or if other less valuable materials had been added to the wreath. He had to do this without damaging the wreath. One day, as the story goes, he was in the community bath house and noticed that the level of water rose as he got in. He realized that this increase in water level was equal to his volume. Thus he would measure the increase of water level resulting from the addition of the wreath to the water and knowing the weight of the wreath determine its density and compare it to the known density of gold. We will use this volume displacement to determine the volume of objects. Here you may have to modify the exercise in order to get decent differences in volume and be able to measure the weight with some reliability using the equipment that you have available to you. Thus, if the procedure calls for one nail and you need more to get a decent volume and/or weight measure you may need to use more nails.

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