n little more than a century. These differ from one another in (1) atomic weight, (2) physical an

means one atom of oxygen.[The symbols of elements will also be used in this book to stand for an indefinite quantity of them; e.g. O will be used for oxygen in general as well as for one

cause it has the least atomic weight. The atomic weight of O is 16, which means that its atom weighs 16 times as much as th

? If O represents one atom, how much does O2 or 2 O stand for? How much by weight? Mo

the elements of which it is composed. How many atoms in the following molec

st name of binaries. How many parts by weight of Na and of Cl in NaCl? What is the molecular weight, i.e. the weight of its molecule? Name KCl. How many atoms in its molecule? Parts by weight of each element? Molecular weight? Does the symbol

ts of the symbol, and shows the number of molecules. How many in thes

he element after which it is written, and shows the

it coefficient one), eight of potassium bromide, ten of hydrogen chloride; also for

nt? Parts by weight of each? Give molecular weight. Is the size of the molecule thereby changed? Name these, give the number of atoms

pal El

Valence. Vap.D. At

27. II, IV ...

120. III, V.

s 75. III

137. II ..

210. III, V .

11. III ..

80. I, (V

d 112. II

40. II .

2. (II), IV

35.5 I, (

. (II),IV,VI ..

9. II, IV ..

63. I, II ..

9. I, (V) ..

(I), III ...

H 1. I

. I, (V) 127.

. II,IV,(VI)

6. II, IV .

7. I ...

24. II ..

55. II, IV, VI

200. I, II

9. II, IV ..

14. (I),II

O 16. I

31. (I),III,

197. (II), IV

39. I ..

28. IV .

108. I ..

23. I ..

r 87. II .

32. II,IV,

8. II, IV .

65. II

ulphur trioxide. Name these: CO2, SiO2, MnO2. The prefixes are: mono or proto, one; di or bi, two; tri or ter, three; tetra, four; pente, five; hex, six; etc. Diarsenic pentoxide is

ement, as HgO. What is a chloride? Define sulphide, ph

eight of each element? What is its molecular weight? To produce FeS a chemical union took place between

phur = Iro

symbols F

c weights,

the proportion of each element which combines, and which should be taken for the experiment. If 56 g. of Fe be used, 32 g. of S should be taken. If we use more than 56 parts of Fe with 32 of S

experiment with copper and sulphur, usi