Search -
A Laboratory Outline of Elementary Chemistry
A Laboratory Outline of Elementary Chemistry Author:Alexander Smith Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. Excerpt from book: Section 3mark. The lowest point of the meniscus must be opposite the mark (Fig. 3). Pour this water into a test-tube and place a narrow rubber band round the test-tube at the level of the lowest po... more »int of the meniscus. Measure and place in the test-tube a second 5 c.c. of water. Mark with a second rubber band the new position of the meniscus. Make in your notebook a full-size drawing of the test-tube, and Fig. 3 show the positions of the bands. Observe carefully the proportions of the tube occupied by 5 c.c. and by 10 c.c. of water, so that when directed in future to use, say, "about 10 c.c." of a liquid or a solid you may be able to judge the amount by the eye. b. Fill the graduated cylinder with water to the highest mark. Fill the evaporating dish with water from the cylinder, note the volume of water remaining, and subtract to learn the capacity of the dish. Record all the figures in your notes. Repeat with the flask. c. What is the weight of 1 c.c. of water [p. 422] ? What weights of water do the evaporating dish and the flask hold? EXERCISE 3. Weighing And Density. Object: textit{To learn to weigh and to learn how to measure densities. Apparatus: Balance. Evaporating dish. Graduated cylinder. 20 c.c. pipette (one for every 10-20 pupils). Materials: Roll sulphur. Sodium chloride (sat. sol.). « a. Weigh the evaporating dish (dry) on the balance to the nearest decigram (0.1 g.) and record the weight. In doing this, record first the weights missing from the box. Then record the weights on the pan of the balance, and note whether the numbers agree. Finally, re-count the weights to make Section 4sure that no error has ,been made. In all weighings with the balance, count the weights three times, as just described. Place in the dish about 10 g. of pieces of roll sulphur (no particles or dus...« less