# Finding Average Molarity: SF in Data

• frozonecom
In summary, when calculating the average molarity of a substance, it is important to consider the significant figures of the data. In this case, the two recorded molarities both have 2 significant figures. To find the average molarity, the two molarities should be added together and then divided by 2. When dividing, the resulting answer should have the same number of decimal places as the data with the least number of decimal places. In this case, it would be 0.187 M with 3 decimal places. However, when reporting the final answer, there is a debate on whether to use 0.0935 M (with 4 significant figures) or 0.094 M (with 2 significant figures
frozonecom
Significant Figures in Data

Suppose I have two recorded Molarity of a certain solution.
And the data I have are:

0.092 M and 0.095 M --- which both has 2 significant figures.

If I were asked to get the AVERAGE MOLARITY of my substance, then I'd do:

(0.092 M + 0.095 M)/2 = My AVG. MOLARITY.

Since 2 is an exact number, I will not base the SF of my final answer to that number.
Instead, I'd base it to my Molarities, but I know I should do the addition first, since they're enclosed in a parenthesis. (following PEMDAS)

0.092 M + 0.095 M = 0.187 M ----- (It should have 3 decimal places, since that is my least decimal place in my data)

Then, dividing my answer by 2, should I report it as:

0.0935 M ----- since 0.187 has 3 SF
OR
0.094 M ------- since my initial working data only has 2 SF?

Which one is more correct? Which one should I follow and why?

Last edited:
Anyone??

I would quote (0.0935 +- 0.0004) M, where the 4 comes from the assumption that both initial values have an uncertainty of 0.0005 each and the remaining part is error propagation.
If you cannot give an explicit uncertainty for some reason, I think I would prefer 0.094 M.

## What is molarity?

Molarity is a unit of concentration that measures the number of moles of a solute dissolved in one liter of solution.

## Why is finding average molarity important?

Finding average molarity is important because it allows scientists to accurately determine the concentration of a solution, which can impact the outcome and effectiveness of experiments and chemical reactions.

## How do you calculate average molarity?

To calculate average molarity, divide the number of moles of solute by the volume of the solution in liters.

## What is the significance of SF in data when finding average molarity?

SF, or significant figures, are important when finding average molarity because they indicate the precision and accuracy of the measurement and can affect the final result of the calculation.

## What are some common sources of error when finding average molarity?

Some common sources of error when finding average molarity include miscalculations, inaccurate measurements, and incomplete dissolving of the solute in the solution.

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