Calculator Black Box Lab:



Calculator Black Box Lab:

Activity one:

Purpose: to demonstrate the relationship between grams and numbers of particles, through calculator functions and visual representation

Introduction: In chemistry one of the most important relationships is between number of particles and mass and moles . This lab will help represent these concepts using familiar mathematical terms.

Objectives: Identify the units of the output data.

-Determine the mathematical relationship between the input and the output data.

-Recognize the underlying Chemistry to the numbers you are given.

-Prepare a visual representation of the transitions between mass, moles, particles and volume.

Procedure: find and record the mass of five nails.

- find and record the mass of five pieces of pie plate scraps.

- Record in the table.

|Mass of element A (L1) |Mass of element B (L4 ) |

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| | |

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- Enter the values from “A” into list one.

- Enter the values from “B” into list four.

- MAKE SURE THE DATA IS PROPERLY ENTERED AND ONLY IN L1 AND L4

- Run the program DOMAGIC on your calculator.

- Select Stat / Edit on your calculator to see the results.

- Now you must determine the mathematical relationship between the numbers given.

- Graph the stat plot

- For metal A (nails): List one vs. List two (List two as the X value)

- For metal B (scraps): List four vs. List five (List five as the X value)

- Use linear regression to determine a slope for both lines. Y=ax+b (L2, L1, Y1)

- (note to get Y2 go to vars then y-vars select 2 and Y2 will be entered then add ) and hit enter will get the appropriate slope of 55.847 and 26.8915

Follow Up: What values on the periodic table do the slopes seem similar to?

The units for list one (y values) are?

The units for list two (x values) are?

The slope (molar mass) has units of and has a value of .

Since the regression equation passes through (or very close) to the origin, the equation can be paraphrased as y = mx. Substitute MM for molar mass and n for number of moles in the equation.

The equation that has just been found can be used to convert moles to grams and grams to moles for any pure substance. We now know that list two and list five correspond to moles.

Do the following steps for List three and List six.

- Graph the stat plot

- For metal A (nails): List three vs. List two (List two as the X value)

- For metal B (scraps): List six vs. List five (List five as the X value)

- Use linear regression to determine a slope for both lines.

The slope is : .

The number should be the same for both elements and is the number of particles in one .

Since the regression equation passes through (or very close) to the origin, the equation can be paraphrased as y = mx. Substitute N, number of partcles, for Y and n, moles, for x.

What are the equations used by the calculator to convert the numbers?

Complete the following data table:

| |Element A |Element B |

|Slope of mass vs. moles | | |

|Slope of ? vs. moles | | |

The constant slope can be considered a physical constant for all elements, however, the other number, the molar mass is unique to all elements.

PART TWO:

We have seen the relationship between mass, moles, and number of particles. However, we will now see if there is a relationship between volume and mass/ moles/ number of particles.

Procedure: Run program MOMAGIC.

- Bring up STAT/ EDIT and examine the results.

- List one holds the molar mass of a solid element and list two holds the density for the same.

- Construct a scatter plot of L2 (density) vs. L1 (molar mass).

- Does the graph have any apparent mathematical relationship?

- List three holds the molar mass of some gaseous element, List three holds the density for the same.

- Create a scatter plot of L2 vs. L1 (L1 in x).

- Calculate the regression equation for the scatter plot.

- Write down the equation and add it to your plot.

- Calculate the slope for the graph.

Follow up: What are the units of the slope (g/L)/(g/mol)?

- What is the relationship between density and molar mass and when does it exist?

- Substitute into the equation y = mx the terms molar mass, MM, for x, and density, D for y

- Can this slope be described as a physical constant, similar to Avogadro’s number, since it appears to hold true for all gaseous elemants?

- What is the numerical value and unit for this constant: .

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