Lab Assignment: Density of an Unknown Solid

OBJECTIVE

Given an unknown solid you should be able to correctly calculate the density of that solid. You should be able to use density to solve problems involving mass and volume.

Pre-Lab Activities

1. Read Lab 3

2. Complete PhET Sims online Pre-Lab Activity.

Lab Activities

1. Find the Density of the Unknown Samples.

2. Your Lab Instructor will initial the Title Page of Your Lab to indicate that you have attended the lab, completed the required lab activities, cleaned your lab bench and all equipment used, and returned all lab equipment to its designated space. A Lab Report that is not initialed in the Checkout box may not be graded. It is at the discretion of your Lab Instructor.

INTRODUCTION TO DENSITY AND SPECIFIC GRAVITY

The experimental purpose of this lab is to determine the density of a solid. You will use the information you learned in lab 2 about accuracy, precision, and significant figures as measured in the laboratory to use error analysis to evaluate your data.

DEFINITIONS

Density is defined as mass per unit volume. Density is a fundamental property of matter.

It is necessary to state the conditions of pressure and temperature because density varies as these conditions change. This is particularly true in the case of gases.

Calculating Density

Choose Same Mass and complete the following table.

To determine the volume of a buoyant block that floats you can hold it under the water.

IMPORTANT - Remember to use the Significant Figure rules you learned in Lab 2.

2. Choose Same Volume and complete the following table

3. Choose Same Density and complete the following table

4. Choose Mystery and complete the following table

5. Click on show table to determine the identity of the mystery blocks.

1. Find the density of the samples assigned to you by your Lab

Instructor.

a. You should record its identity.

b. Describe the appearance of the sample.

c. You are to determine the density of your sample using two different methods.

d. You need to write a procedure giving the steps you will follow to find the density of the sample for each method. The procedure should be written as numbered list and should be clear and easy to follow. A fellow student with no knowledge of density should be able to follow your procedure.

e. You may use any lab equipment that is visible in the classroom. You may also use the analytical balances.

f. Your lab instructor must initial your procedure before you do anything else.

g. Once your procedure is initialed by your lab instructor you are to follow the steps in your procedure to find the density of your sample.

h. Obtain the actual density of your sample from your Lab Instructor and find the percent error in your density calculation.

i. Use your procedure to determine the density of the second sample. You can choose which method to use.

Lab Report Density

Title Page

CHECK OUT Lab Instructor's Initials Your Lab Instructor will initial the Title Page of Your Lab to indicate that you have attended the lab, completed the required lab activities, cleaned your lab bench and all equipment used, and returned all lab equipment to its designated space. A Lab Report that is not initialed in the Checkout box may not be graded. It is at the discretion of your Lab Instructor.

Please tear this page out of your lab manual and turn it as the title page of your lab report.

PhET SIMS Worksheet Experimental Procedure must be signed by lab instructor list of steps and safety precautions

Results and Calculations Page(s) state your results with correct units and correct number of significant figures show all calculations used to determine your results compare your experimental results with accepted results (if available), calculate the percent error if your percent error is large, explain why your results differ from accepted results list potential sources of error (both systematic and random error)

how might you improve the experiment in order to obtain results closer to the accepted result

Answer the following question using complete sentences. Write neatly and legibly or type your answers. Use a separate sheet of paper.

1. Density is a property of matter. Is density a physical or chemical property?

Is density an intensive or extensive property?

2. You can express the density of an object in units of kg/L or in units of g/mL.

How is the density of an object in kg/L related to its density in g/mL?

3. You are given a sample block of an unknown metal. The block displaces 3.24 mL of water and has a mass of 62.5429 g. What is the density of the unknown metal? What is the metal? Cite the source you use to answer this question. See the HCC Library Homepage for information on citing sources.

4. Watch Bunsen burner safety video in preparation for next week's lab.

Attachment:- Density-of-an-Unknown-Solid.rar