What is more precise...a graduated cylinder or a flask?

Question

Density 1:

Pipet 25.00 mL of a salt solution into a flask to measure the density of the salt solution.

Density 2:
Measure between 9-10 mL of a salt solution into a graduated cylinder to measure the density of the salt solution.

Which density measurement should be more precise?

Density 1:

Mass of 25 mL solution + flask, g 124.257 , 124.298
Mass of flask, g 95.366 , 95.366
Mass of 20 or 25 mL solution, g 28.891, 28.932
Volume of solution, mL 25.00 , 25.00
Density of salt soluation, g/mL 1.156, 1.157
Average density of salt solution 1.157
Standard Deviation 0.0007071

Density 2:
Mass of cylinder + solution, g 61.724 , 61.755
Mass of cylinder, g 50.238 , 50.239
Mass of solution, mL 11.486 , 11.516
Volume of solution, mL 9.91 , 9.89
Density of solution, g/mL 1.16 , 1.16
Average density of salt solution, g/mL 1.16
Standard deviation 0.0

The standard deviation is my calculation...but I think I calculated it wrong...from my calculations, I see the graduated cylinder as being more precise...is that right though?

The flask was a Erlenmeyer Flask that the 25.00 mL salt solution was pipeted into...then weighed from the original weight of the flask and then with the solution...the density was calculated...and the standard deviation...which I do not think I calculated right...

The next was the graduated cylinder which we were supposed to measure between 9-10mL of salt solution and record the measurement as volume...weigh the sample and calculate density and standard deviation.

We were then to explain which is more precise in measurements...

Our chemistry instructor is horrible...and we are all lost.

Answer 1

Both the flask and the cylinder are graduated so any measurement with is correct, and just as valid. Therefore the containers are equivalent and have little influence on the accuracy of the measurements. Since each container has a similar neck above the salt solution the shape of the container has little to do with the accuracy.

So the only relevant factors are the SIZE of specimens. If you have a larger sample then you will get a better AVERAGE solution for the question on density. If you have a smaller sample then you have a less representative sample so it would be less accurate.

The key word is GRADUATED is both containers are graduated then they are calibrated to give a measurement that conforms to a specific measurement, and all measurements should be equal. to any measurements in any other container.

The next question is how you plan to determine the salt content. If you are just weighing the samples and comparing that weight to the weight of pure water then the only difference If you are boiling the water and analyzing the contents then the round flask will spread the heat more evenly and allow for a uniform boil, but that won't change the resulting salt residue contents. Unless the contents themselves are changed by the heat applied. Then there is the Buchner Flask, the Florence Flask, the Erlenmeyer Flask or the Retort. All of which are different shaped and designed for different uses, but in the final analysis if they are graduated then the graduation means that the shape doesn’t matter so you are left with the size of the sample.

Answer 2

A volumetric flask can be moe accurate for preparing solutions. Graduated cylinders are more accurate for getting a number of measurements. For problem 1, if you pipette 25ml, that is accurate for the volume. To determine the density you need to know the mass of the flask and the mass of the solution in it. Then the formula, mass divided by volume to get density. For problem 2 You need to know is it 9 or 10 ml for the volume. Then you can measure the mass of the cylinder and determine the mass of just the solutionThen use the formula again. In neither case were you actually measuring density. You were measuring volume and then mass. If you did each accurately ,both will be accurate. The one question is the 9 yo 10 ml part. You need one or the other..

Answer 3

the comparison is not actually between a flask and a graduated cylinder

the comparison is between a pipet and a graduated cylinder

a typical pipet will measure volume more precisely than a typical graduated cylinder

a very specialized very narrow graduated cylinder could be much more precise than a poorly made pipet

the answer they are looking for is probably "density 1"

if you just make a pipet measurement yourself and then make a graduated cylinder measurement you will see the difference

siting that meniscus on the cylinder can introduce more error than on the pipet

Answer 4

Graduate cylinder. Flask volume markers are not that great and if you miss it by little you measurement goes way off.

Well and your density 1 has more solution to work with stupid flask.

Answer 5

nvrm i only read the first part of your question and i dont feel like doing the rest of it cuz i dont want to spend my time off school doing stuff i would do in school although normally they should be equally precise