Langsung ke konten utama

Formulas of Compounds

  A compound is a distinct substance that is composed of the atoms of two or more elements and always contains exactly the same relative masses of those elements. In light of Dalton's atomic theory, this statement simply means that a compound always contains the same relative numbers of atoms of each element. Foe example, water always contains two hydrogen atoms for each oxygen atom.
The types of atoms and the number of each type in a each unit (molecule) of a given compound are conveniently expressed by a chemical formula.
  In a chemical formula, the atoms are indicated by the element symbols and the number of each type of atom is indicated by a subscript, a number that appears tothe right of and below the symbol for the element.
  The formula for water is written H2O, indicating that each molecule of water contains two atoms of hydrogen and one atom of oxygen (the subscript 1 is always understood and not written).

Komentar

Posting Komentar

Postingan populer dari blog ini

How the Other Half Lives

      Lord Manners was a rich and famous banker. When he died, he was given a magnificent funeral which was attended by hundreds of famous people. The funeral was going to be held in Westminster Abbey. Many ordinary people lined the streets to watch the procession. The wonderful black and gold carriage was drawn by six black horses. The mourners followed in silence. Lord Manners was given a royal farewell. Two tramps were among the crowd. They watched the procession with amazement. As solemn music could be heard in the distance, one of them turned to the other and whisper in admiration, "Now that's what I call really living!"
1 komentar
Baca selengkapnya

The Mystery of the Talking Shoe

     Tracy Evans didn't have to be at work till ten, so she ignored her alarm clock. But she woke up with a start when she heard a stange sound coming from her wardrobe. What was it? It must have been a mouse, Tracy thought. No, it can't have been. She knew there were no mice in her room. I must be careful, Tracy said to herself as she opened the wardrobe. There, in front or her, was the lovely pair of wedge-shaped sandals she had bought the day before. Then she heard the sound again. "It must be Coming from my sandals!" she cried. She picked them up and, sure enough, one of them was "talking". Tracy had to be at work at ten, but she still had enough tome to visit Mr.Lucas, her shoemaker. He removed the wooden heel and they were both amazed to see a white larva eating the wood. Mr.Pope, of the Natural History Museum, solved the mystery. "These shoes must have been imported from brazil. An insect must have laid its eggs in the tree from which the shoes ...
Posting Komentar
Baca selengkapnya

Who has the last say?

Some people are always saying that they don't built cars as they used to be. What nonsense! I walked round the beautiful new Ferrari again, admiring its lines, when my thoughts were rudely interrupted. "Will you be here long?" a voice asked sharply. "I haven't made up my mind yet," I said, loolking up at a sour-faced traffic warden. "Well, you can't stop here," he told me "Who says so?" I asked him cheekily. "I said so," he said to me. "It says here," he added, "in case you can't read. "No, waiting"." "You read very well. Go to the top of the class! I told him, "but I'll make my own decisions." "oh, will you?" the traffic warden asked. "Then so will I and I've decided to give you a ticket, " he said to me with relish as he began filling out a form. "Go, ahead,"I told him."This car doesn't belong to me anyway. I ...
Posting Komentar
Baca selengkapnya