A student performs the following procedure:

Procedure

1. Measure 25 grams of an unknown solid.

2. Measure 200 grams of water.

3. Pour the unknown solid and water into beaker, which weighs 50 grams.

4. Stir the solution.

The student records the following observation:

Observation

About half of the unknown solid dissolves and the other half settles to the bottom of the beaker.

Part A:

The student calculated the combined weight of the unknown solid and the water to be 275 grams. Describe the mistake the student made in this calculation.

Part B:

Describe how stirring the solution will affect the total amount of matter in this investigation.

Match the words in the left column to the appropriate blanks in the sentences on the right. (a) this is the law of definite proportions: all samples of a given compound, regardless of their source or how they were prepared, have proportions of their constituent elements. (b) this is the law of conservation of mass: in a reaction, matter is neither created nor destroyed. (c) this is the law of multiple (c) this is the law of multiple blank: when two elements form two different compounds, the masses of element b that combine with 1 g of element a can be expressed as a ratio of small whole-numbers. in this example, the ratio of \rm o from hydrogen peroxide to \rm o from water = 16: 8 \to 2: 1, a small whole-number ratio.: when two elements form two different compounds, the masses of element b that combine with 1 g of element a can be expressed as a ratio of small whole-numbers. in this example, the ratio of o from hydrogen peroxide to o from water = 16: 8 → 2: 1, a small whole-number ratio.