the instruction state, "weigh about 5 g sodium chloride".give the minimum and maximum amount of sodium chloride that would satisfy these instructions.
Weighing an object depends on the device you are using. When using a balance, record all the masses to include one uncertain digit and all certain digits. This instruction indicates that the measured quantity of sodium chloride should be 5 g plus or minus a small quantity. In this example 4.8 to 5.2 S will satisfy these requirements. To weigh exactly 5.00 g or 5.000 g wastes time since the directions call for approximately 5 g. Sometimes it is necessary to measure an amount of material precisely within a stated quantity range. Suppose the directions read, "weigh about 5 g of sodium chloride to the nearest 0.001 g" This instruction does not imply that the amount is 5.000 g but that it should be between 4.8 and 5.2 S and measured and recorded to three decimal places. Therefore, four different students might weigh their samples and obtain 2.141 g, 2.0 g, 2.4 g, I.812 g, and 1.887 g each respectively, and each would have satisfactorily followed the directions.