if you are asked to "obtain about 3 g of sodium chloride weighed to the nearest 0.001 g should you weigh out exactly 3.000 g? explain your answer.

You may but that isn't required.

About 3 g means you could weigh
2.995, 2.900, 3.001, 3.050, 3.100, 3.200, etc. You want somewhere close to 3g and I would think anywhere between 2.500 and 3.500 would be ok. Others may think a better range is 2.750 to 3.250. It really depends upon the experiment being conducted. The spirit of the question means you want APPROXIMATELY 3 g but whatever amount you weigh you want it to be weighed to the nearest 0.001 g.

If you are asked to "obtain about 3 g of sodium chloride weighed to the nearest 0.001 g should you weigh out exactly 3.000 g? explain your answer.

To answer this question, let's first understand the concept of significant figures. In science, significant figures represent the level of precision or accuracy of a measured value. The number of significant figures in a value indicates the level of certainty in the measurement.

Now, given that you are asked to obtain about 3 g of sodium chloride, weighed to the nearest 0.001 g, it implies that the intended level of precision is up to three decimal places (0.001 g). Weighing out exactly 3.000 g would exceed this precision requirement.

To weigh out about 3 g of sodium chloride with the required precision, you should consider the significant figures to be used for the 3 g measurement. In this case, "about 3 g" suggests that the number 3 itself is estimated. Therefore, using the full significant figures of the value 3, you could weigh out approximately 3.000 g or slightly less, as long as the value is within the tolerance of ±0.001 g.

It's important to note that "about 3 g" is not a highly precise measurement requirement, so it allows for a small amount of variation. By using the appropriate number of significant figures, you can achieve the desired level of precision while not exceeding it.