EXERCISES
1. Why does the chemist use distilled water in making solutions, rather than filtered water?
2. How could you determine the total amount of solid matter dissolved in a sample of water?
3. How could you determine whether a given sample of water is distilled water?
4. How could the presence of air dissolved in water be detected?
5. How could the amount of water in a food such as bread or potato be determined?
6. Would ice frozen from impure water necessarily be free from disease germs?
7. Suppose that the maximum density of water were at 0° in place of 4°; what effect would this have on the formation of ice on bodies of water?
8. Is it possible for a substance to contain both mechanically inclosed water and water of crystallization?
9. If steam is heated to 2000° and again cooled, has any chemical change taken place in the steam?
10. Why is cold water passed into C instead of D (Fig. 24)?
11. Mention at least two advantages that a metal condenser has over a glass condenser.
12. Draw a diagram of the apparatus used in your laboratory for supplying distilled water.
13. 20 cc. of hydrogen and 7 cc. of oxygen are placed in a eudiometer and the mixture exploded. (a) How many cubic centimeters of aqueous vapor are formed? (b) What gas and how much of it remains in excess?
14. (a) What weight of water can be formed by the combustion of 100 L of hydrogen, measured under standard conditions? (b)What volume of oxygen would be required in (a)? (c)What weight of potassium chlorate is necessary to prepare this amount of oxygen?
15. What weight of oxygen is present in 1 kg. of the ordinary hydrogen dioxide solution? In the decomposition of this weight of the dioxide into water and oxygen, what volume of oxygen (measured under standard conditions) is evolved?