Picture this in your mind as you read it: You weigh an empty, clean, dry beaker on the balance (scale). It weighs 32.15 grams. Y
ou are instructed to measure out 2.0 grams of solid X and put it in the beaker you just weighed. Using weighing paper, you weigh out 2.0 grams of solid X and carefully transfer it into the beaker. You now weigh the beaker WITH the solid in it and get a mass of 34.40 grams. What is the weight of the solid, using the correct number of significant figures? 2.0 grams, just as you weighed it before putting it in the beaker. 2.00 grams, using the correct number of significant figures. The mass is 34.40 g -32.15 g -2.3 grams The mass is 34.40 g -32.15 g -2.25 grams
The mass of the solid X must be the total mass (beaker + solid X) less than the mass of the beaker. Then:
mass of the solid X = 34.40 - 32.15
mass of the solid X = 2.25 g
The difference of 0.25 g must occur for several problems: an incorrect weight in the balance, the configuration of the balance, the solid can be hydrophilic and absorbs water, and others.
