Lab 1 density. A characteristic property.pdf

Lab 1 density. A characteristic property.pdf - Lab 1...

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Unformatted text preview: Lab 1: density. A characteristic property! Wednesday, September 27, 2 017 6:44 PM Background: -­ Solid substances are denser than liquids. -­ Ice floats on liquid water. Because ice is less dense than water. -­ All matter has mass and volume, which means it takes up space. -­ Relationship between these values defines a fundamental characteristic of matter known as density. -­ Property used to identify elements or compounds. -­ Density = mass per unit volume of a substance : -­ -­ The standard metric unit for density is grams per milliliter (g/mL) -­ For solids, the cubic centimeter is used instead and the unit of density is then grams per cubic centimeter. -­ Numerically the two volume units are equivalent, because 1 cm cubed is equal to 1 mL. -­ Example: density of copper is 8.69 g/mL. If you calculate the density of an unknown metal to be 8.69 g/mL the metal is most likely copper. Measuring Mass -­ The mass of a substance can be measured using a balance. Measuring the volume of a liquid -­ Usually measured using volumetric equipment ( graduated cylinder) -­ The surface of a liquid will curve and form a meniscus, concave or convex Measuring the volume of a solid -­ Measured either by taking length measurements or using water displacement. -­ Water displacement is most valuable for measuring the volume of the solids that are in lumps, powders, irregular shapes -­ When a solid is placed into water it will displace, push the water. The volume of the object is the difference between the initial and final water volume: V solid = V 2 – V 1. Short Answer Density: A Characteristic Property Short Answer Density: A Characteristic Property Experiment 1: Find the Density of Various Liquids Lab Results 1. In this experiment, you took measurements for three volumes of water. Use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Mass of graduated cylinder (g) Volume of water (mL) Mass of graduated cylinder plus water (g) 2. In this experiment, you took measurements for three volumes of ethanol. Use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Mass of graduated cylinder (g) Volume of ethanol (mL) Mass of graduated cylinder plus ehtanol (g) Data Analysis 1. In this experiment, you took measurements for three volumes of water. Use the data you collected during the experiment to calculate the quantities in the table below. In this experiment, the volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density can only be as precise as the volume. Total mass of water (g) Density of water (g/mL) Average density of water (g/mL) 2. In this experiment you took measurements for three volumes of ethanol. Use the data you collected during the experiment to calculate the quantities in the table below. Please note that in this experiment the volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density c an only be as precise as the volume. Total mass of ethanol (g) Density of ethanol (g/mL) Average density of ethanol (g/mL) volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density c an only be as precise as the volume. Total mass of ethanol (g) Density of ethanol (g/mL) Average density of ethanol (g/mL) Experiment 2: Identify an Unknown Liquid Lab Results 1. In this experiment you took measurements for three volumes of an unknown liquid. Use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Mass of graduated cylinder (g) Volume of unknown liquid (mL) Mass of graduated cylinder plus unknown liquid (g) Data Analysis 1. In this experiment you took measurements for three volumes of unknown liquid. Use the data you c ollected during the experiment to calculate the quantities in the table below. Please note that in this experiment the volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density c an only be as precise as the volume. Total mass of unknown liquid (g) Density of unknown liquid (g/mL) Average density of unknown liquid (g/mL) Experiment 3: Find the Density of Various Metals Lab Results 1. What was initial volume of water and the initial mass of the graduated cylinder with water? 2. For each of the iron measurements, use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Total volume of water plus iron (mL) cylinder with water? 2. For each of the iron measurements, use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Total volume of water plus iron (mL) Total mass of iron in the cylinder (g) 3. For each of the aluminum measurements, use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Total volume of water plus aluminum (mL) Total mass of aluminum in the cylinder (g) Data Analysis 1. For each of the iron measurements, use the data you collected during the experiment to calculate the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Please note that in this experiment the volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density c an only be as precise as the volume. Net volume of iron (mL) Density of iron (g/mL) Average density of iron (g/mL) 2. For each of the aluminum measurements, use the data you collected during the experiment to calculate the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Please note that in this experiment the volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density c an only be as precise as the volume. Net volume of aluminum (mL) Density of aluminum (g/mL) Average density of aluminum (g/mL) 3. Create and save a graph of mass (y-­axis) v ersus the v olume (x-­axis) for iron. Click the graphing icon to create your graph. Click the box underneath the graph to show the trendline. It will automatically calculate your s lope and intercept. The density equals the slope of the graph. 4. Create and save a graph of mass (y-­axis) v ersus the v olume (x-­axis) for aluminum. Click the graphing icon to create your graph. Click the box underneath the graph to show the trendline. It will Click the box underneath the graph to show the trendline. It will automatically calculate your s lope and intercept. The density equals the slope of the graph. 4. Create and save a graph of mass (y-­axis) v ersus the v olume (x-­axis) for aluminum. Click the graphing icon to create your graph. Click the box underneath the graph to show the trendline. It will automatically calculate your s lope and intercept. The density equals the slope of the graph. Experiment 4: Identify an Unknown Metal Lab Results 1. For each of the unknown metal measurements, use the data you collected during the experiment to record the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Total volume of water plus metal (mL) Total mass of metal in the cylinder (g) Data Analysis 1. For each of the unknown metal measurements, use the data you collected during the experiment to calculate the quantities in the table below. Remember to pay attention to significant figures and record all masses and volumes with all the decimals provided by the lab. Please note that in this experiment the volume is your least precise measurement containing fewer significant figures than the mass. Therefore, the density can only be as precise as the volume. Net volume of metal (mL) Density of metal (g/mL) Average density of metal (g/mL) Conclusions 1. Given that the density of glycerol is 1.261 g/mL, how much will 15.00 mL of glycerol weigh? 2. Given the density v alues for the metals in the table below, will the same volume of your unknown metal be lighter or heavier than copper? Metal Density (g/cm3) zinc 7.13 tin 7.28 2. Given the density v alues for the metals in the table below, will the same volume of your unknown metal be lighter or heavier than copper? Metal Density (g/cm3) zinc 7.13 tin 7.28 copper 8.96 silver 10.49 lead 11.36 3. Why do you think it is important to record your data with all the decimals provided by the instruments even if they are zero? How will this help with data analysis? ...
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