Recently somebody asked about the meaning of CaCl2. This was not a simple question, because she mentioned that CaCl2 consists of one Ca2+ ion and two Cl- ions.
Okay, I should clarify this problem. I say a problem rather than a question, because this is a serious misconception, its really dangerous, it can make the big problem in the future. Many concepts that relate to this concept will go wrong.
CaCl2 is an ionic compound. Remember that ionic compound has an ionic bond. What is the difference between ionic bond and covalent bond? In general, ionic bond is a bond between cations and anions, as a result of transferring electron(s) from metal to non metal. On the other hand, covalent bond is a bond between non metal atoms that occurred because of sharing electron pair between atoms. For example, CO2.
Now think about how cations and anions bond. Each cation attracts anions and each anion attracts cations, so they link together, ones surround the other. As a result, they form a giant structure. They attract each other strongly, so they are very close one of another. There is a lattice energy with the negative enthalpy change. The more negative the enthalpy change, the strong the ionic bond of the compound. Because all the ions link together, this is called CRYSTAL structure rather than MOLECULAR one. A crystal has an empirical formula and a molecule has a molecular formula.
A molecule, for example CO2, is a simple structure. A CO2 molecule consists of one C atom and two O atoms. The molecular formula shows the type of elements and the number of atoms. However, a molecule is very small, we can not see.
CaCl2 is an empirical formula. CaCl2 consists of Ca2+ ions and Cl- ions with the ratio of Ca2+ : Cl- = 1 : 2. We can not say that CaCl2 contains one Ca2+ ion and two Cl- ions. Its really a big mistake. Its wrong, do not mention again that CaCl2 is a molecule, or the small part of crystal consists of 3 ions. No, do not mention it any more. Because crystal is a giant structure, so we can see that the crystal can grow up.
The properties of crystal compounds are different with molecular compounds. These properties are very important in learning other concepts. You have to understand in dept about the above explanation. Please do the exercises that relate to these concepts. You can use my other blog that I have written in Indonesian language, in GEMAR KIMIA. You can find this from my blog list.
Okay, now I hope every of you can understand better about the difference between empirical formula and molecular formula.
Okay, I should clarify this problem. I say a problem rather than a question, because this is a serious misconception, its really dangerous, it can make the big problem in the future. Many concepts that relate to this concept will go wrong.
CaCl2 is an ionic compound. Remember that ionic compound has an ionic bond. What is the difference between ionic bond and covalent bond? In general, ionic bond is a bond between cations and anions, as a result of transferring electron(s) from metal to non metal. On the other hand, covalent bond is a bond between non metal atoms that occurred because of sharing electron pair between atoms. For example, CO2.
Now think about how cations and anions bond. Each cation attracts anions and each anion attracts cations, so they link together, ones surround the other. As a result, they form a giant structure. They attract each other strongly, so they are very close one of another. There is a lattice energy with the negative enthalpy change. The more negative the enthalpy change, the strong the ionic bond of the compound. Because all the ions link together, this is called CRYSTAL structure rather than MOLECULAR one. A crystal has an empirical formula and a molecule has a molecular formula.
A molecule, for example CO2, is a simple structure. A CO2 molecule consists of one C atom and two O atoms. The molecular formula shows the type of elements and the number of atoms. However, a molecule is very small, we can not see.
CaCl2 is an empirical formula. CaCl2 consists of Ca2+ ions and Cl- ions with the ratio of Ca2+ : Cl- = 1 : 2. We can not say that CaCl2 contains one Ca2+ ion and two Cl- ions. Its really a big mistake. Its wrong, do not mention again that CaCl2 is a molecule, or the small part of crystal consists of 3 ions. No, do not mention it any more. Because crystal is a giant structure, so we can see that the crystal can grow up.
The properties of crystal compounds are different with molecular compounds. These properties are very important in learning other concepts. You have to understand in dept about the above explanation. Please do the exercises that relate to these concepts. You can use my other blog that I have written in Indonesian language, in GEMAR KIMIA. You can find this from my blog list.
Okay, now I hope every of you can understand better about the difference between empirical formula and molecular formula.
1 comment:
g ada karbon bu......
apakah bisa ditambahkan artikel tentang senyawa karbon n' hidrokarbon?
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