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Chem Lab: Comparing Density Graphs Name: ___________________________ Hour: ________ Purpose: Compare the densities of a variety of materials by observing graphs. Materials: Triple Beam Balance, Coal, Galena, Rose Quartz, Sulfur, Block of Wood, Graduated Cylinder, Ruler Pre- Lab Questions: 1. Define the following terms in your own words: Volume-________________________________________________________________________________ Mass-_________________________________________________________________________________ Density-_______________________________________________________________________________ 2. Formula for density is 3. Units: D= Volume-__________ Mass-______________ Density-______________ Find the Density: 1. Find the mass of each object using the triple beam balance. 2. Record your findings in the table below. Don’t forget the units. 3. To find the volume of the objects: a. Put about 50 ml of water in the graduated cylinder AND record the exact amount in the space labeled “Initial Volume”. b. Drop the object into the cylinder and record the total mL in the space labeled “Total Volume”. This is the volume of the water and the volume of the object. c. Find the difference between Initial and Total. Record in the column marked “Volume.” Object Mass (Object) Initial Volume (water) Total (water + object) Volume (object) Solve for Density (show your work) Coal (black) Galena (silver) Rose quartz (pink) Sulfur (yellow) Question: 1. Why didn’t use the formula, volume=length X width X height, to find the volume of the above objects? _____________________________________________________ More on back! Chem Lab: Comparing Density Graphs Name: ___________________________ Hour: ________ Density of a Block of Wood: Find the mass, volume and density of wood. Show your work and include units. Mass= ________ units: ______ Volume=_______ units: ______ Density= _______ units: ______ Follow Up Questions: 1. Considering your work above, why does wood float on water? Hint: Think about the Density of Water lab. 2. Consider the graph to the right: a. What is the independent variable? b. What is the dependent variable? c. What does the slope of this graph represent? d. Which of the three elements in the graph has the greatest density? e. Which of the three elements has the smallest density? 3. Imagine you made a graph similar to the one above for the four substances in the first part of the lab (coal, galena, rose quartz, sulfur). List them in order from the substance with the steepest slope to the substance with the least steep slope: 4. Directly proportional means that as one value increases, the other value also increases. Inversely proportional means that as one value increases, the other value decreases. Do mass and volume appear to have a direct or an indirect relationship?