Identify Unknown Substances Using Density

I. LIQUID - Identification of an Unknown Liquid: Using the physical properties of Solubility, Density, and Boiling Point.

Density was an important part of this lab. Density can be defined as the ratio of the mass of an object to the volume. To find the density of an object, simply divide mass and volume. The equation looks like this: D=M/V. Density is an intensive property that depends only on the composition of a substance, not the size of the sample.

This experiment was performed to determine the difference in density between pre-1982 pennies and post-1982 pennies. In addition, we were given an unknown substance and our task was to configure what it was through calculating its volume,mass, and density. Furthermore, we were being introduced to the procedures of displacement in this experiment as well. All together, we were given the task of finding out why there was a difference in density between the two pennies. My partner, Michael Sapawa, and I first had to measure the mass of both pennies using a scale. Then we calculated the volume of the samples with graduated cylinders through the method known as displacement. We then applied our schema and drew out the formula for density, which

Experiment 2 “Density” was about how to measure the mass and volume and determine the density of water, alcohol, and a solid. For this lab, we begin by calculating the mass of empty graduated cylinder and the mass of 25 mL of tap water. After taking the mass of water and cylinder, we record it on “Density of Water: Data Table”. Since we did not have enough time of complete the whole lab, so we skipped the procedure to measure the density of alcohol. We jumped to the next procedure, which was density of a solid. For that we used a copper and it density 8.95. For this lab, my partner and I did not make any mistakes or errors. But, for better improvement I think we should have more time to complete the whole lab. I felt like we was rushing through

If I fill up two different containers with different amounts of water, then I will be able to understand the density of the two different mass/volumes of two different containers.

The primary goal of this laboratory is to correctly identify an unknown substance. To achieve this task, one may use various tests that reveal both chemical and physical properties of a substance. By comparing the results of a known substance and the unknown substance, one may eliminate alternative possibilities and more accurately predict the undisclosed compound. Furthermore, by performing these tests, data can be collected and verified regarding chemical and physical properties of the unknown. Understanding the chemical properties of a known substance aids one’s understanding of the unknown based on comparative analysis of the results of the tests.

This experiment was performed to observe differences in density based on the chemical makeup of an object. Pennies minted before 1982, pennies minted after 1982, and an unknown metal sample was tested to see if there were any differences in their densities. Ten pennies from each category and the metal sample were weighed using a scale to find mass and the displacement method was used to find their volumes. The masses and volumes were then used to calculate the densities of the pennies (D=m/v). The density of the pre-1982 pennies were 8.6 g/mL while the post-1982 pennies were 6.9 g/mL. The metal sample’s density was 1.7 g/mL. Following the experiment we were given the real densities of each item to calculate the percent error with the formula

We found the density of the unknown object #6 to be 5.9(g/mL). We then use the table to identify the metal, and the result is that the name of the metal is zinc. Since the density of zinc is 7.14 and that is the closes number to our density, we determine that our unknown object is zinc. Our average density for the unknown liquid #5 is .779(g/mL). The closes density of a known liquid on the table is .792(g/mL), so we concluded that our liquid #5 is cyclohexane which has a density of

2. In order to calculate the density of a solid or liquid sample, what measurements are needed?

In Measuring and Understanding Density, several experiments were performed to find density of regularly shaped objects, irregularly shaped objects, liquids and gasses. An additional experiment was done to find the specific gravity of a sampling of liquids. The purpose of the experiment was to provide a better understanding of density and to be able to extrapolate unknowns based upon these calculations. The experiments yielded data in keeping with Kinetic-molecular theory in regards to the density of water versus its temperature. Key measurements and formulae were also used to determine densities of metal and plastic objects as well as irregularly shaped rocks. It is possible to find the density of an object (be it liquid, gas or

Conclusion: The purpose of this lab was to find the relationship between the mass and the volume of the four samples. The densities from least to greatest were shortest(4), short(3), medium(2), and longest(1). Density can vary with temperature, and that could cause errors in the collected data. A real world application of density is icebergs. Icebergs float because they are less dense than the water around them. The icebergs are made of frozen freshwater but they are surrounded by very cold salt water. Initially, salt water has a higher density than freshwater and the low temperatures of the water cause the density to increase even more. The salt water and its increasingly high density allows for the less dense icebergs to float. Knowing this about density is good to know so we can figure out how things in the world work, like how and why massive icebergs float in the middle of the

formulas, such as percent by mass. Eventually, we were able to determine the empirical formula of the unknown substance.

The purpose of this lab is to identify the molecular mass of the volatile liquid. The molecular mass needs to be identified because it is a property that helps determine a substance. Since the substance is volatile, or easily evaporated, the liquid can be converted into gas. As the substance converts into gas, the ideal gas law, PV=nRT, can be used to calculate the the number of moles. Once, the number of moles is calculated, it is used in the molecular mass equation, which is, molecular mass = grams /mol. The grams of the gas is taken directly by measuring the substance, and the moles is taken indirectly through the calculations of the ideal gas law. The result of the calculations should be the molecular mass of the substance.

The purpose of this lab is to measure densities and understand how it can be used to identify unknown substances. Density is determined by a substance mass divided by its volume. It's possible to identify a substance by its density because density is an intensive property that does not change with the size of the substance.Density is also an intensive property , which depends on the type of matter not the amount. Density is also a qualitative observation which is descriptive info about a substance. In addition temperature can affect a substance's density, because it affects its mass and its volume.

The purpose of this experiment is to identify an unknown substance by measuring the density and boiling point. I will be able to conclude which substance is my own from a list of known options stating what its real boiling point and density is.