Mass, Volume and Density

Edit Experiment

VIDEO LINKS:

Lab Experiments (Write protocols based on the videos then complete your protocols as you perform experiments in class):

  1. Weighing
  2. Measuring Volume

Data analysis and calculations (Use these if you need help with your data and calculations)

  1. Measurements
  2. Significant figures

For today the prelab will be written as a group at the beginning of class. Future pre-labs will be due before your lab class meets and will include Experimental Protocol, Chemical Table and Equipment Table.

 

Experimental Protocol

(Analysis) Watch the experiment videos. Take notes on the protocols. Stop the videos and re-watch as necessary to acquire details of the procedure. Write out the protocol for each part of the experiment.  (It can be written in sequential steps.  Complete sentences are not necessary.)  This is the protocol you follow, so be detailed.

Part 1: Find the mass of a regular object.

 

Part 2: Find the volume of a regular object.

 

Part 3: Find the mass of an irregular object.

 

Part 4: Find the volume of an irregular object.

 

Part 5: Find the density of a regular and an irregular object.

Chemical Table

(Representation) Prepare your chemical table including the materials you use in the experiment.  Here is a general template that you may use.
Chemical Name Chemical Formula Molar Mass (g/mol) Hazards Reference PPE
Sodium Chloride NaCl 58.5 Skin irritation https://fscimage.fishersci.com/msds/21105.htm  
           
           
           

Equipment Table

(Analysis) Identify the equipment (type AND size) needed for the experiment and include the name and an image (picture) of each.  Be sure to describe the equipment, how to use it, and why it is suitable for this use.
Equipment Name Equipment Picture Intended Purpose

Data Collection

(Acquiring competencies) Following your detailed protocol, perform all the experiments. Record your observations and take pictures of your key steps in the process. Your observations and images need to be incorporated in your data section and this section should be as detailed as possible as you will use this information to complete your discussion.   Take every measurement 3 times and then average the values for best accuracy. Find both the mass and the volume for every object you investigate.        

Part 1: Find the mass of a regular object.

 
Object name Mass 1 Mass 2 Mass 3 Average
 

Part 2: Find the volume of a regular object.

Object name length Width Height Volume
Average Average Average Average
Average Average Average Average
 

Part 3: Find the mass of an irregular object.

 
Object name Mass 1 Mass 2 Mass 3 Average
 

Part 4: Find the volume of an irregular object.

 
Object name Initial Volume Final Volume Difference
Average Average Average
Average Average Average

Data Processing

  1. (Manipulation) Find the density of a regular and an irregular object:
Object name Mass Volume Density Known value
 
    1. (Manipulation) Calculate the % error in the density calculations using the following formula:
% error=((experimental value-true value))/(true value)×100% Make this number positive (take the absolute value).  Your instructor will have the true values.
  1. (Representation) Draw a graph with mass on the y-axis and volume on the x-axis. For water, draw a red line starting at (0,0) and having mass = volume for all points. Plot your data points for each of your objects in your experiment on the graph.
  2. (Experimental design) Design and test an experiment to determine the mass and volume of a small piece of plastic.
  3. (Interpretation) Predict the region where most metals will appear on the graph.
  4. (Interpretation) Predict the region where most plastics will appear on the graph.
  5. (Assumptions and analysis) Fill in the following table using the observations and data from your experiments.
Assumptions made Testing the assumption If assumptions are wrong ...
The distilled water is pure Evaporate it and check for residue The density would change depending on the density of the contaminant
The objects used for displacement does not absorb water Take the mass before placing in water and again after it was removed form water and dried
Mass shown on the scale is accurate Different scales show different mass for the same object
 

Discussion

For the discussion you have two options:
  1. Answer each question below in sufficient detail to address each task, so more than 1-2 sentences.
  2. Write a minimum half-page (12 font, single spaced) discussion on the experiment conducted this week. The assignment will be graded on completeness, clarity of the explanations and the meaningful integration of the collected and calculated data. Correct grammar and appropriate format for the chemical formulae and chemical reactions is expected. You may use the outline included at the end of this document on how to build your essay to address each category.
 
  1. (Acquiring competency) Using at least one of your recorded mass and volume measurements, identify its required components (number and unit).
  2. (Analysis) Identify the number of significant figures in all your recorded measurements. Describe what process you used to decide how many numbers were significant.
  3. (Lab skills) Describe how you measured the volume of the regular and irregular objects. Use one of your measurements for each to demonstrate the process.
  4. (Acquiring competency) Describe how you calculated the density of the regular and irregular objects. Use one of each of your calculations to demonstrate the process.
  5. (Analysis) Give a supported argument for whether density is affected by the amount of material in your sample.
  6. (Analysis) Use one your density calculations as an example to show how you determined the number of significant figures in your answer.
  7. (Analysis) Propose a relationship between the density of an object and its ability to float in water. Explain your reasoning.
  8. (Experimental design) Propose another experiment to determine the density of something that interests you around your house. Testing your proposed method is a good way to ensure that you are correct. Don’t hesitate to share your pictures!

Recommended Discussion Outline:

The techniques I used in this experiment were… By dividing the mass by the volume, the amount of each was no longer important because… In this experiment we assumed .... The purpose of the experiment was (Hint: it was not to find the density of a bunch of random objects) … By performing this experiment, I learned…