Basic Chemistry: Chemical Formulas and Equations

When you want to study chemistry, surely you will not be separated from Chemical Formulas and Equations. Because it is one of the foundations of Chemistry itself.

When you get the hang of it all, you'll find it easier to learn more chemistry. For that, please refer to the explanation below carefully.

Source

Coat Of the Elements

To express the composition of the compound and to describe the qualitative and quantitative changes occurring when the reaction is, precisely, briefly and directly, therefore, chemical symbols and formulas are used.

Source

The first element symbol is formed from the first letter of the International (Latin) name, and most elements, with the second letter contained in the same name.

The first letter of an element is capitalized. For example, C (carbon), H (hydrogen), O (oxygen), N (nitrogen), K (potassium), Al (aluminum), Cr (chromium), Na (Sodium), and many other elements in the periodic table .

The symbol, in addition to being used as a qualitative reference, is also very useful in the determination of quantitative analysis. In general, the element symbol represents 1 atom or some specific element representing 1 gram of atom.

Thus, C denotes 1 atom of carbon element or 1 gram of atom (12.011 g) of carbon. Similarly, O represents 1 oxygen atom or 1 gram atom (15.9994 g) of oxygen. Or H which states 1 gram atom (1.0080 g) hydrogen.

You will find many of the above figures rounded up in a matter called the relative atomic mass (Ar).

Empirical Formulas

The empirical formula is used to express the composition of the material whose molecules comprise more atoms. It consists of the symbols of the elements that make up the compound.

Source

The number of atoms of a particular element in the molecule is written as a subscript behind the element's emblem (but 1 is never written as a subscript) because the symbol itself has already declared an atom.

Thus, carbon dioxide molecules are formed from one carbon atom and 2 oxygen atoms, then the empirical formula is CO2. In water molecules, there are two hydrogen atoms and one oxygen atom, then the empirical formula of water is H2O.

Rules of Writing of Chemical Formulas

Source

Although there are no strict rules concerning the order of atomic symbols in a chemical formula, for inorganic substances, are generally symbols

Metal or Hydrogen is written early. Then follow with non metals and finally oxygen.

Whereas in the organic substance formulas, the usual order is C, H, O, N, S, P.

Knowledgeable Function Empirical Formulas

If the empirical formula of a compound is known, it can be drawn conclusions about the physical and chemical properties of the compound. Example:

• From the empirical formula, it can be known what elements are contained in the compound.
• The relative molecular mass (MR) can be determined simply by summing the relative atomic mass of the elements that make up the compound.
• Make it easy to calculate the relative amount or percentage composition of certain elements.

Structure Formula

By understanding the concept of valence, we can also know the composition of the compound which can be expressed by the structure formula. Any valence of an element may be regarded as an arm or a hook, through the chemical bonds formed.

Each valency can be described as a single line painted out of the element's symbol, eg H-, O =, and others.

The structural formula of compounds can be expressed by lines painted between atoms, such as H-Cl, H-O-H, and others. This structure formula is widely used in organic chemistry.

Aromatic compounds, such as Benzene (C6H6), are described in hexagonal form and have single, intermittent double bonds (conjugate bonds).

Chemical Equations

A chemical reaction can be identified by chemical equations. This equation contains the formula of the elements that react on the left side and the formula of the right reaction. Some things to consider in writing chemical equations, including:

Source

1. In the equation of the reaction, a single arrow arrow (→) is used instead of the "equals" or "results" sign. In an equilibrium reaction, the alternating arrow (⇄) is used to indicate that the reaction can travel both ways.
2. The formula of the compound used in the chemical equation must be written correctly.
3. The chemical equation must be balanced by the use of stoichiometric numbers so that the sum of each atom is equal on both sides.
4. The amount of charge on the left side must equal the amount of charge on the right side.
5. When charged particles (ions and electrons) are involved in the reaction, the charge must be clearly indicated (eg Pb2 +) and equilibrium. The amount of left-side payload should equal the amount of right-side payload.

Example:

Ca (OH) 2 + H3PO4 → Ca3 (PO4) 2 + H2O

Being:

3Ca (OH) 2 + 2H3PO4 → Ca3 (PO4) 2 + 6H2O

From the above reaction equations, we can see that each side has 3 calcium atoms (Ca), 2 phosphorus atoms (P), 12 hydrogen atoms (H), and 14 oxygen atoms (O). So it can be said that the above reaction equation is equivalent.

Source

To make the reaction look perfect, it is worth mentioning the physical properties of each compound itself.

In this case, the letter "s" is used to denote solid (solid), the letter "l" to express the liquid (liquid), and the letter "g" for the gas. As for the species dissolved in water used the letter "aq" (aqueous).

The letters are written in parentheses and placed behind the formula. For example: AgBr (s), H2O (l), O2 (g), and H3PO4 (aq).

In chemical equations, it is also commonly used downward arrows (↓) to indicate the formation of a precipitate, while for upward arrows (↑), states the existence of gas liberation.

Here is my discussion of the basic science of chemistry entitled "Basic Chemistry: Chemical Formulas and Equations". Science that I have very little to share with my readers, then I leave a link for readers so easy to understand furthermore advanced. Thank you from me, @manah