Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: sidoniaknight on September 06, 2019, 06:12:17 PM
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This is for a post-lab. See attached. We measured the mass of water that was measured from three pieces of equipment: Grad. Cylinder, Pipet, and a Buret. We are supposed to use the density of water to calculate the volume of water measured out. The calculated volume that is closest to 6mL is the more accurate measuring instrument. Here's my problem. They give the density as 1 g/mL . Should I consider this as 1 sig fig? If so, then all my measurements would be reported as 6mL due to sig. fig's multiplication/division rule. At least, that's what I am assuming. I fell as if this defeats the purpose of the question which brings me to this lovely forum. I would appreciate any insight into the matter. Thank you!
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In calculations we consider the Sig Fig of only measured values and not of the given values
Here significant figures of the answer will depend on the number of significant figures in the volume which you have measured using different apparatus.
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Sigs figs are affected by measurments. "Exact" numbers, like the density of water(because the definition of 1g is the weight of 1ml of water), conversion factors(60 minutes in an hour) and the number of discrete objects(12 pencils, 5 dogs) do not affect them. Accuracy is defined as closeness to the true answer, while precision is defined as consistency in measurments. You can be one and not the other, both, or neither.
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Thanks for the answer folks. Do I need to somehow flag this post as answered?