Ok so we had a mass determinations lab in chemistry. We were supposed to use both a triple beam balance scale and an electronic scale to precision.
We first weigh our beaker on both scales (i did it on the electronic first), then record the weight. Then we have three objects, we put the first one in the beaker and record the weight of the beaker + the object...then we subtract the beaker weight by itself - the beaker + the object to get the weight of the object by itself. Then we do this for the other two objects until we have gotten this data for all three objects...then I did the same for the triple beam balance scale...
Here are my calculations:
Calculations:
Electronic Scale:
Mass of empty beaker: 49.112g
ID number of object Mass of beaker plus object – empty beaker Mass of object itself
Transparent Cube A
65.814g – 49.112g=16.702g
Cork B
49.695g - 49.112g=0.583g
Steel Cylinder C
78.026g – 49.112g=28.914g
Triple Beam Balance Scale:
Mass of empty beaker: 49.1g
ID number of object- Mass of beaker plus object – empty beaker- Mass of object itself
Transparent Cube A
65.95g – 49.1g=16.85g
Cork B
49.85g – 49.1g=.750g
Steel Cylinder C
78.2g – 49.1g=29.1g
This is my calculations. What I need to do now is something about translating my calculations to sig figs? I think in my case it's decimal points. But I'm not sure how to translate these calculations into the right decimal points or sig figs, please help?
I'm not sure which number is the exact number to not consider but I'm assuming it's the weight of the beaker. I am led to believe I am supposed to base the final calculations on the decimal points of the initial weight of the beaker + the object
Please just tell me the final numbers that I need to put on my lab book. People talked about precision and systematic error I don't get it I just need to write down the numbers on my lab book because I have two hours till class starts
In other words, just do my work for me.
Suggestion: Start earlier next time.
In order to properly express your calculations in terms of significant figures, you need to determine the precision of the measurements and apply the rules of significant figures accordingly.
The basic rules for significant figures are as follows:
1. Non-zero digits are always significant.
2. Leading zeros (zeros before any non-zero digits) are not significant.
3. Captive zeros (zeros between non-zero digits) are always significant.
4. Trailing zeros (zeros at the end of a number after a decimal point) are always significant.
5. In calculations involving addition or subtraction, the final result should be rounded to the least number of decimal places of any value being added or subtracted.
6. In calculations involving multiplication or division, the final result should be rounded to the least number of significant figures of any value being multiplied or divided.
Now, let's apply these rules to your calculations:
1. Mass of Empty Beaker:
- Electronic Scale: 49.112g
- Triple Beam Balance Scale: 49.1g
Since the numbers do not contain any zeros or decimal places, they are already in their most precise form.
2. Mass of Object A:
- Electronic Scale: 16.702g
- Triple Beam Balance Scale: 16.85g
Both measurements have four significant figures. In this case, you should use the measurement with the least number of decimal places, which is the electronic scale measurement (16.702g).
3. Mass of Object B:
- Electronic Scale: 0.583g
- Triple Beam Balance Scale: 0.750g
Both measurements have three significant figures. Here, the number with the least number of decimal places is the electronic scale measurement (0.583g).
4. Mass of Object C:
- Electronic Scale: 28.914g
- Triple Beam Balance Scale: 29.1g
The electronic scale measurement has five significant figures, while the triple beam balance scale measurement has three significant figures. In this case, use the measurement with the least number of significant figures, which is the triple beam balance scale measurement (29.1g).
Therefore, the final numbers to write in your lab book considering significant figures are:
- Mass of Empty Beaker:
- Electronic Scale: 49.112g
- Triple Beam Balance Scale: 49.1g
- Mass of Object A:
- Electronic Scale: 16.702g
- Triple Beam Balance Scale: 16.9g
- Mass of Object B:
- Electronic Scale: 0.583g
- Triple Beam Balance Scale: 0.750g
- Mass of Object C:
- Electronic Scale: 28.914g
- Triple Beam Balance Scale: 29.1g
As for precision and systematic errors, precision refers to the degree of consistency and reproducibility of a measurement. In this case, precision would be determined by comparing the measurements you obtained from the electronic scale and the triple beam balance scale. If the measurements are consistent with each other, it indicates higher precision.
Systematic error, on the other hand, refers to a consistent deviation from the true value of a measurement. It can occur due to various factors, such as equipment calibration issues or procedural errors. If you notice a consistent difference between your measurements and the expected values, it might suggest a systematic error. This could be investigated further by troubleshooting the equipment and reviewing the experimental procedure.
However, for the purpose of completing your lab book, it should suffice to record the final numbers with the appropriate significant figures as indicated above.