Percent Error Formula: Find the % Error in Lab w/ 10 mL Water

[lindseyam]

Homework Statement

I need to find the percent error from a lab I did in class. i have all the data but I don't know what would be used for the theoretical weight and experimental weight in the percent error formula. I used 10 mL, 25 mL, and 50 mL of water in a graduated cylinder. I'll just used the 10 mL information. I got 8.9 mL for the meniscus. The weight of the cylinder was 75.35 grams and with the water, 82.92 grams which makes the weight of the water 7.57 grams. So the problem once again is what I would use for the theoretical weight and experimental weight in the percent area formula. I would ask my teacher but he's not that friendly and makes me feel like an idiot.

Homework Equations

The Attempt at a Solution

 

[Borek]

Please describe the experimental procedure, experiment is unclear to me - I can't see a connection between 10 mL, 8.9mL and 7.57g.

 

[lindseyam]

Please describe the experimental procedure, experiment is unclear to me - I can't see a connection between 10 mL, 8.9mL and 7.57g.

I had 10 mL of water in the graduated cylinder and got a meniscus of 8.9 and the water weighs 7.57 grams. and the percent error formula is (theoretical - experimental) divided by theoretical X 100. Would theoretical and experimental be?

 

[Borek]

It still doesn't make sense.

I had 10 mL of water in the graduated cylinder and got a meniscus of 8.9

I don't get it. If the meniscus was at 8.9, you had 8.9 mL of water in cylinder, not 10 mL.

Would theoretical and experimental be?

 

[DeeNos]

The percent error formula is used to determine the accuracy of an experimental result compared to a theoretical value. In your case, the theoretical value would be the expected weight of the water based on its known density (at a given temperature) and the volume used. The experimental value would be the actual weight of the water measured in the lab.

To find the theoretical weight, you can use the formula: mass = density x volume. The density of water at room temperature is approximately 1 gram per milliliter. So for 10 mL of water, the theoretical weight would be 10 grams.

Using the given data, the percent error can be calculated as follows:

Percent error = | (experimental value - theoretical value) / theoretical value | x 100

= | (7.57 g - 10 g) / 10 g | x 100

= 0.243 x 100

= 24.3%

Therefore, the percent error in your experiment with 10 mL of water is 24.3%. This indicates that your experimental value was 24.3% lower than the theoretical value, which could be due to factors such as measurement errors or experimental limitations. It is important to analyze the sources of error in your experiment and try to improve them for more accurate results in the future.