1. Set up the Sheet Layout and Labels:
Open a new Excel workbook and enter the following labels in the specified cells:
| Cell | Content/Label |
|---|---|
| A1 | Volumetric Solution Preparation: HCl Molarity & Factor |
| A3 | Input Data: |
| A4 | Mass of Trometamol (g): |
| A5 | Volume of HCl used in titration (mL): |
| A7 | Constants: |
| A8 | Molar Mass of Trometamol (g/mol): |
| A9 | Nominal Molarity (M): |
| A11 | Calculation Steps: |
| A12 | Moles of Trometamol (mol): |
| A13 | Moles of HCl reacted (mol): |
| A14 | Volume of HCl used in titration (L): |
| A16 | Results: |
| A17 | Actual Molarity (M): |
| A18 | Factor: |
| A20 | Acceptance Criteria: |
| A21 | Molarity Lower Limit (M): |
| A22 | Molarity Upper Limit (M): |
| A23 | Factor Lower Limit: |
| A24 | Factor Upper Limit: |
| A26 | Validation Status: |


2. Enter Fixed Values and Formulas:
Now, enter the fixed values and the formulas into the corresponding cells. Pay close attention to which cells are referenced in the formulas.
| Cell | Formula/Value | Explanation |
|---|---|---|
| B4 | Leave Blank (This is for user input - e.g., 0.6055) | This is where you will manually enter the mass of trometamol used in your standardization. |
| B5 | Leave Blank (This is for user input - e.g., 12.00) | This is where you will manually enter the volume of HCl solution consumed during your titration. |
| B8 | 121.1 | Molar mass of Trometamol. |
| B9 | 0.50 | Your nominal (theoretical) molarity for the diluted HCl|
| B12 | =B4/B8 | Calculates moles of trometamol from its mass and molar mass. (e.g., 0.6055 / 121.1) |
| B13 | =B12 | Since the reaction is 1:1, moles of HCl reacted equal moles of trometamol. |
| B14 | =B5/1000 | Converts the volume of HCl used from mL to Liters. (e.g., 12.00 / 1000) |
| B17 | =B13/B14 | Actual Molarity Calculation: Moles of HCl reacted divided by the volume of HCl in Liters. (e.g., 0.005000 / 0.01200) |
| B18 | =B17/B9 | Factor Calculation: Actual Molarity divided by the Nominal Molarity. (e.g., 0.4167 / 0.50) |
| B21 | =0.90B9 | Calculates the lower limit for molarity (0.90 times the nominal 0.50 M). Result should be 0.45. |
| B22 | =1.10B9 | Calculates the upper limit for molarity (1.10 times the nominal 0.50 M). Result should be 0.55. |
| B23 | 0.90 | Fixed lower limit for the factor. |
| B24 | 1.10 | Fixed upper limit for the factor. |
| B26 | =IF(AND(B17>=B21,B17<=B22,B18>=B23,B18<=B24),"ACCEPTED","NOT ACCEPTED") | Validation Status: Checks if Actual Molarity is within its range AND Factor is within its range. Displays "ACCEPTED" or "NOT ACCEPTED". You can apply conditional formatting to this cell (e.g., Green fill for "ACCEPTED", Red fill for "NOT ACCEPTED"). |


3. Format Cells for Protection:
By default, all cells in Excel are set to be "Locked" when sheet protection is applied. We need to unlock the input cells so the user can type into them.



Unlock Input Cells:

Select cells B4 and B5.

Right-click on the selected cells and choose "Format Cells...".

Go to the "Protection" tab.

Uncheck the box next to "Locked".

Click OK.


Ensure Other Cells are Locked (Default State):

Select the entire sheet by clicking the gray square in the top-left corner (above row 1 and left of column A).

Right-click on any selected cell and choose "Format Cells...".

Go to the "Protection" tab.

Ensure the box next to "Locked" is CHECKED. (This is usually the default).

Ensure the box next to "Hidden" is UNCHECKED. (This makes formulas visible).

Click OK.



4. Protect the Sheet:
This step will activate the protection settings you've just configured.



Go to the "Review" tab on the Excel ribbon.

Click "Protect Sheet" in the "Protect" group.

In the "Protect Sheet" dialog box:

You can optionally enter a password to unprotect the sheet later (recommended).

Under "Allow users of this worksheet to:", make sure at least "Select locked cells" and "Select unlocked cells" are checked. You can choose other options based on your needs, but these two are essential for user interaction.


Click "OK". If you set a password, you'll be prompted to re-enter it.
Now, when you try to click on a cell containing a formula (like B17 or B18), you will see the formula in the formula bar, but you won't be able to edit it. You will only be able to enter data into cells B4 and B5.