An introduction to chemistry, with practical questions: designed for beginners in the science

Front matter

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Preface

J. HE science of chemistry is considered as a part of a polite and liberal education for both sexes, and is taught in most of the literary institutions of our country. Its utility and the interest which it is calculated to excite, cannot fail to recommend it to the attention of every inquisitive mind. It is so intimately connected with the physical sciences in general, that no one of them can successfully be. cultivated entirely independent of it

Chemistry is not confined to one department of nature it takes a wide range through all the works of creation, and subjects all material bodies to its laws. " The solid matters comprising the terrestrial mass of the globe we inhabit; the aqueous fluids which penetrate its cavities or float on its surface ; the more gaseous fluids which surround this ponderous mass ; the agencies of heat, light and other fleeting substances expanded through the mighty space, are subjects upon which the chemical philosopher may dwell with infinite profit and delight."

Chemistry extends itself into the minute concerns of active life, and is the fostering hand of innumerable important arts, and the various discoveries made in the science are so many acquisitions to those arts.

The science is no longer, as formerly, confined to the laboratory of the artist, but it ranks among the first in philosophical research. It has been enriched, and is continually undergoing improvements by philosophers, in every part of Europe. Works on cheHstry are daily

IV. PREFACE.

issuing from the press, which are excellent in themselves, and have a tendency to advance the student in the knowledge and improvement of the science. But there are few that are calculated, in every respect, for beginner?.

Tiie Conversations on Chemistry, by Airs. Bryan, is a very useful and popular work, and has been through many editions both in Europe and America. The subjects are treated in a very pleasing and familiar manner. Great obligations are due to the amiable authoress for the good she has done to the cause of the science. But the exper diency of adapting this as an elementary work, at the present time is questioned by many instructors, as great improvements and discoveries have been made in the science since that work was written ; many subjects are there inserted which have no relation whatever to this country, and the colloquial manner of treating the subjects necessarily occupies a great portion of the book, which might otherwise be appropriated to subjects of more in> portance.

Works which treat of the rudiments of chemistry should be perspicuous, as it embraces a variety of subjects, and those, owing to the revolutions which the science is continually undergoing,arc too often involved with other matters, not immediately connected with first principles. The consequence of which is, the student finding many objects arresting his attention, at once, all equally gratifying and attractive, looses sight of those elements, by which only, a permanent foundation can be laid. The author is no advocate for those who pretend to display all the elegance of the temple of sjcience at once, into which the novice is introduced without preparation or ceremony, where idleness and industry are permitted to participate equally in the same rewards. He believes-

PREFACE. V-

that the candidate for excellence must proceed with caution, perseverence and labour; that there is but one road to science, which at first is rugged, steep and difficult ; that as we advance, we acquire strength to encounter new difficulties, till finally we are qualified to relish the sublime beauties that await the persevering and industrious.

We ought alwaj's to bear in mind the maxim,

An attempt has been made in the following work ; to bring the principles of chemistry into as small a compass as possible, and in a concise manner to exhibit the various subjects treated of by the most eminent chemical writers of the present day.

The work is designed for beginners in the science, it became therefore, necessary to consult the interests both of the instructor and pupil. Few chemical works appear to have had this object in view. Authors have gone upon the supposition that the learner has already become acquainted with the elements, and is qualified to pursue it^ through all the intricate subjects, in the elaborate works of the present day, The consequence is, that either much time is lost in attempting to acquire a knowledge of the subject, or an aversion is contracted which ends in a total neglect of this useful and pleasing science. To obviate these inconveniences is the design of the author in the following pages ; whether he has succeeded in his object, he leaves to a candid and impartial public to judge.

With regard to imparting instruction, the author considers the plan he has adopted in this work as preferable. From long experience as an instructor, he feels a confidence in recommending the interrogatory method, as attended with the greatest utility. Questions at the end of 1*

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each chapter very much assist the learner ; and are likewise conwnient for the instructor. Each question having a reference to a particular section, the answer may be easily committed to memory ; by which means the remarks of the author are readily comprehended, and much time saved, which is too often employed in turning over the leaves of a book, searching for the object, without a suitable guide to direct to the place ; this has a tendency to discourage rather than promote exertion.

No pretensions, are made to originality in the following pages ; the work is a compilation. Neither is it designed to supersede any other. It is an introduction for the purpose of enabling students to commence with more pleasure and success those excellent works of Gorham, Thomson and Henry, which should follow this where a correct knowledge of the science is- desirable. In this compilation, recourse has been had to the works of various chemical writers ; from which such extracts have been made as were thought necessary for an introduction. If the subjects have been- properly arranged, and treated in a clear and perspicuous manner, the author will be rewarded by a consideration that he has performed an important task ; but this he dares not flatter himself that he has been able, fully, to accomplish.

Some, perhaps, may object that remarks have beeit made, and passages inserted, which will not be easily understood by beginners, particularly in the chapter on Chemical Equivalents and the Atomic Theory ; but the author is not conscious of inserting any thing which is not admitted by the most eminent of the European chemists, and which he is confident is conformable to the most accurate and rigid experiments, as well as to just theory. In examining the remarks of authors on the above subject, for the. purpose of making a selection, being limited

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as to the size of the work, he found that he must either omit the articles altogether, or treat them agreeably to the plan of the authors from whose works they have been extracted. The atomic theory has been adopted r under various modifications, by most scientific men of the present day - r and most treatises of chemistry that have been published within the last ten years have a reference to it, especially in the proportions of the different compounds -> the work, therefore, in his opinion, would have been very defective without some notice of the theory ; especially as one of the principal objects in the compilation was to prepare the pupil, by a knowledge of the first principles of the science, to enter upon fuller and more elaborate treatises, it became,, therefore, necessary to treat the subjects not only in a concise manner, but conformably to the present exalted state of the science. Should any, however, be disposed to omit the chapter on chemical equivalents in the instruction o£ very young persons, it may be done without any derangement of the other parts.

As some acquaintance with what is called Natural and Experimental Philosophy is necessary, previously to entering on the study of chemistry, the work is commenced with some of the rudiments of that science ; but brevity was absolutely necessary,, as the limits assigned to the work would not admit otherwise J> R> C,

Boston, May 10th, 1822.

Table Of Contents

10. 11. 12. 13.

14. 15.

16. 17. 18. 19. 20.

CHAPTER I. Definition, <$*c. — General Laws of Matter

1. Chemistry is the science which investigates the combinations of matter, and the agencies of those general forces whence these combinations are established or subverted.

2. The subjects of Chemical inquiries are particles of matter, both the magnitude and form of which, and the distances within which they act upon each other, are wholly incapable on account of their extreme minuteness to be estimated.

Observation. Authors are not agreed with regard to the etymology of the word Chemistry ; it is generally thought to be of Arabian origin.

3. Matter is the first principle of all natural things, from the various combinations and arrangements of which all bodies are formed.

4. Substance is that which supports the different forms and appearances which are presented to our senses. In common language it means a distinct or definite portion of matter, whether solid or fluid

Observation. The ward substance is compounded of the Latin preposition sub, under, and sto to stand ; it differs from matter, because it impll s a determinate fig- X ure, whereas, matter implies a more general and confused idea of solidity and extension, without any regard to figure.

5. Every kind of substance has certain characteristic properties, such as Solidity, Divisibility, Mobility and Inertia.

6. By solidity or impenetrability, in common language is to be understood the property of not being easily separated into parts.

Observation. If a piece of wood or stone occupy a certain space, they must first be removed before another body can be put in the place ; and though fluids, from their nature, appear at first to oppose such resistance, yet in proper circumstances they will be found to retain th 3 property in an equal degree.

Exp. 1 . Put some water into a tube closed at one end, and insert into it a piston, a piece of wood, or metal, which exactly fit the bore of the tube ; then try to push the piston to the bottom, you will find it impossible, even by the force of the greatest pressure.

Exp. 2. Pour the water from the tube, which will be empty as it is called in common language, but in reality, filled with atmospheric air. In attempting to push the piston to the further end, you will meet with the same resistance as before.

7. We derive our idea of impenetrability from the resistance which we meet with in bodies, whether they be solid or fluid.

8. Divisibility is that property by which matter is capable of being divided into parts, and those parts separated from each other.

Observation. This divisibility is evident in bodies of sensible magnitudes ; w r e can never hy subdividing arrive at a part so small, but we can conceive that it consists of two halves, but how far this actual division may be carried, whether to infinity or whether we should at last arrive at ultimate atoms, which from their nature, are not capable of subdivision, is a point not ascertained.

The actual division of matter may be carried to an amazing extent,so as to approximate to our ideas of infinity.

Illustration 1. A grain of gold is hammered by the gold beaters until it is the thirty thousandth part of a line in thickness, and will cover fifty square inches.— Each square inch may be divided into two hundred strips,, and each strip into two hundred parts v which may be seen with the naked eye ; consequently a square inch contains forty thousand visible parts, which multiplied by fifty, the number of square inches which a grain of gold will make, give two million parts, which may be seen with the naked eye.

2. It has been calculated that sixteen ounces of gold, which, in the form of a cube, would not measure one inch and a quarter in its side,, will completely gild a quantity of silver wire sufficient to surround the globe.

Exp. 1. Put into a quart of water a small piece of nitrate of silver, lunar caustic, not larger than a common pin's head, it will impart a uniform milky colour to the whole liquor.

Exp. 2. Into a pint of water put a small piece of sulphate of copper, blue vitriol, not more than the one hundredth of a grain, it w r ill impart a sensible blue colour to the whole liquid.

9. Mobility is that property by which bodies are capable of being moved from one place to another.

10. Inertia is a tendency which bodies possess of continuing in the state in which they are placed, whether of rest or motion, unless prevented by some external force.

Illustration 1 . A man standing in a boat while it is pushed from the shore, will be in danger of falling backwards, but he will gradually acquire the motion of the boat, and if it be suddenly stopped, he will fall forwards, because his tendency will be to continue in motion.

2. A man riding on full gallop, if the horse suddenly stop, is in danger of falling over the animaPs head, his tody having acquired the motion of the horse.

1 1 . Space has no limits or bounds ; it consists of parts, which may be divided by the mind, but are not capable of actual separation. Its parts are only distinguished by bodies placed in them.

12. Space is either absolute or relative.

13. Absolute space is mere extension, it has no limits or bounds, and is itself immoveable.

14. Relative space is that part of absolute space that is occupied by any body, and is compared by any part occupied by any other body.

15. Motion is either absolute or relative.

16. Absolute motion is the actual motion which bodies possess, independant of each other, and only with regard to the parts of space.

17. Relative motion is the degree and direction of the motion of one body compared with that of another.

Illustration. By this imperceptible motion plants and animals grow, and the greatest number of compositions and decompositions throughout the globe take place.

The temperature of bodies is constantly varying, consequently the particles must be in continual motion, in order to adapt themselves to the size of the body.

18. Accelerated motion is, when the velocity of motion continually increases.

19. Retarded motion is, when the velocity continually decreases.

20. The velocity of uniform motion is estimated by the time employed in moving over a certain space, or by the space moved over in a certain time.

21. To ascertain the velocity, divide the space run over by the time.

22. To know the space run over, multiply the velocity by the time.

23. In accelerated motion, the space run over is as the square of the time, instead of being directly as the time, as in uniform motion.

Illustration. A body falling from a height, moves at the rate of 16 1-12 feet in a second of time, and acquiresa velocity of twice that, or 32 1-6 in a second. At the end of the next second it will have fallen 64 1-3 feet. — - The space being as the square of the times, the squareof 2 is 4, and 4 times 16 1-12 is 64 1-3. And so on.

24. By velocity is meant what bodies would acquire if they should fall through a space where there was no air. Its resistance diminishes considerably their velocity in falling. Therefore in estimating the velocity of bodies, this circumstance must be taken into consideration.

25. A body acted upon by one force will always move in a straight line.

26. Bodies acted upon by two uniform forces, whether equal or unequal, must form a straight Lne. But if one of the forces be not uniform, that is, either accelerating or retarding, the moving bodies will descr.be a curve line.

Illustration. If a ball be projected from a cannon, it receives an impulse, which, if there were no res.stance from the air, and if it were not acted upon by gravity, would cause it to move always _n a straight Lne, bi-t as soon as it leaves tie mouth of the 6annen, gravity acta upcn it, and causes it 10 change its direction to that of a curve.

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27. The momentum of a body is the force with which it moves, and is in proportion to the weight or quantity of matter, multiplied into its velocity.

28. All bodies appear to possess attraction and repulsion, the causes of which are totally unknown.

29. There are various kinds of attraction, viz. the attraction of cohesion ; of gravitation ; electricity ; magnetism ; and chemical attraction or affinity.

30. All the phenomena of chemistry arise from the attractions and repulsions exerted between the particle* of matter.

31. Attraction of cohesion acts only at very small distances. It is by this attraction that bodies preserve their forms, and are prevented from falling to pieces.

Exp. 1. If two leaden bullets have a little scraped from each, so as to make them fit exactly ia those parts^ and they be put together with a. twist, they will adhere so strongly as to require a considerable force to separate them.

Illustration. Hardness, softness, brittleness, ductility and malleability depend upon different modifications of the attraction of cohesion,

32. When a body is in solution, and the attraction of cohesion is exerted suddenly, the particles unite indiscriminately and form irregular masses. But when it acts more slowly, the particles assume a particular arrangement, and form masses of regular figures. This is termed crystallization, and the regular figured masses are denominated crystals.

33. Attraction of cohesion is the cause of the forms in which different bodies exist, and the regular figures which many of them assume.

31. The attraction of gravitation or gravity is the tendency of bodies towards each other, which is exerted at all distances.

35. Every particle of matter in the universe gravitates towards every other particle.

Illustration 1. By the attraction of gravitation, the heavenly bodies are retained in their orbits by their mutual action ; and by this, a stone dropped from a height falls to the surface of the earth.

2. The planets and comets all gravitate towards the sun and towards each other as well as the sun towards them, and that in proportion to the quantity of matter in each.

36. All terrestrial bodies tend towards a point, which* is exactly or very nearly the centre of the earth, consequently bodies fall every where perpendicular to the surface, and on opposite sides in opposite directions.

Observation. If two bodies of equal quantity of matter were placed at ever so great a distance from one another, and left at liberty in free space, and if there were no other bodies in the universe to affect them, they would fall equally swift towards one another, and would maet in a point which was half way between them at first.

37. Gravitation decreases from the surface of the earth upwards as the square of the distance increases.

38. We know nothing of gravity but by its effects,

39. Electric attraction is that exerted by amber, sealing was, and some other substances when rubbed.

Illustration. When amber and sealing wax are rubbed with a silk handkerchief, they attract feathers, dust, &c... from small distances.

40. Magnetic attraction is that exerted by the load stone on iron.

Illustration. The tendency of the needle to the pole is an instance of this attraction.

PRACTICAL QUESTIONS.

What is Chemistry ?

What are the subjects of Chemical inquiries ? What is matter ?

What is substance ?

What are the characteristic properties of matter ? What is understood by solidity ?

Do fluids possess solidity ?

Illustrate this by experiment.

How do we obtain our ideas of impenetrability ? What is divisibility ?

Illustrate this.

What experiment can you exhibit to confirm it, What is mobility ?

What is inertia ?

Illustrate it.

What is space ?

How is space divided T

What is absolute space ?

What is relative space ?

How many kinds of motion are there ?'

What is absolute motion ?

What is relative motion ?

Illustrate it.

What is accelerated motion ?

What is retarded motion ?

How do you estimate the velocity of retarded motion f

How do you estimate the space run over ?

How is the space m accelerated motion ?

Illustrate this.

What is meant by velocity ?

How will a body move that is acted upon by one force ?

How if acted upon by two forces ?

Illustrate it.

What is the momentum of a body ?

What do all bodies appear to possess ?

How many kinds of attraction are there ?

From what do all the phenomena of Chemistry arise 2

What is attraction of cohesion ?

Illustrate this.

What is the effect when the attraction of cohesion is exerted suddenly.

What is the cause of the forms of different bodies ?

What is the attraction of gravitation ?

How does every particle of matter gravitate ?

How is it with regard to the planets and comets ?

How with regard to terrestrial bodies ?

What would be the consequence suppose there were only two bodies in the universe, and they placed at a distance from each other ?

How does gravitation decrease from the surface of the earth ?

What do we know of gravity ?

What is electric attraction ?

Illustrate it.

What is magnetic attraction ?

Illustrate it.