Writing and Naming Chemical Formulas

Writing and Naming Chemical Formulas

Writing formulas

Steps:

1.       Write the symbols for the ions.

2.       Crisscross the numbers and write them as subscripts.

A.      Binary compounds

It consists of two elements which are formed by metals and non-metals.

                Examples:

·         K⁺   and   Cl^-                    KCl

·         Ca²⁺  and   Br^-                       CaBr₂

·         Mg²⁺ and  N^3-                  Mg³N²

Exercises:

Write the formula for the following:

1.       Strontium fluoride

2.       Calcium sulfide

3.       Calcium phosphate

Naming Formulas

1.       In naming binary compounds containing metals with fixed oxidation number,  the metal is named first, followed by the nonmetal with the ending –ide.

               Example:

              Ca₃N_{2  -}  calcium nitride

             Exercises:

1.        CaBr₂                              4. KCl

2.       Mg₃N₂                              5. Na₂O

3.       Al₂S₃

2.       In naming binary compounds containing metals with variable oxidation numbers, the oxidation number must be specified.

Two types of naming system:

1.       Stock system – the oxidation number is indicated by Roman numeral in parentheses.

2.       Classical system – the suffixes –ous and -ic are used to denote the lower and higher oxidation states. 

Cu²⁺ O^2-     Cu₂O

                      Copper (I) oxide

                      Cuprous oxide

                Exercises:

1.       Fe²⁺   and  Cl^-                     4. Pb²⁺   and   I^-

2.       Sn⁴⁺   and   F^-                      5. Hg²⁺  and   Br^-

3.       Cu²⁺  and O^2-

B.      Binary compounds containing two non-metals

Prefixes are used

CO – carbon monoxide

CO₂ – carbon dioxide

Exercises:

1.       Name the following compounds

1.       NO                         4. P₂O₅

2.       SO₂                        5. PCl₅

3.       CCl₄

2.       Write the chemical formulas of the following:

1.       Nitrogen dioxide                        4. sulfur trioxide  

2.       Dinitrogen trioxide                    5. Diphosphorus pentoxide

3.       Carbon disulfide

C.      Metals with Polyatomic Ions

·         Polyatomic ion is a stable group of atoms that carries an overall electrical charge.

·         Parentheses are placed around the polyatomic ion and subscript is written just after the close parenthesis whenever a multiple polyatomic ion is necessary.

                 Mg²⁺ OH^-      Mg(OH)₂

·          Parentheses are not used when single polyatomic ion is present.

                                KKClO₃                  CaCO₃                 NaHCO₃

  Exercises:

                   Write the correct formula for

1.       Strontium bicarbonate                     4. Magnesium phosphate

2.       Ammonium nitrate                           5. Copper (III) carbonate

3.       Iron (III) sulfate

Give the name of the following:

1.       K₂CrO₄                                               4. FeSO₄

2.       Zn(NO₃)₂                                             5. Sn(OH)₄

3.       CuClO₃

D.      Acids

1.       Binary

Hydrogen and a Nonmetal

·         The word hydrogen comes first; then the second word is made by affixing the

suffix  –ide to the root word of the nonmetal.

HCl   hydrogen chloride

·         When these substances are dissolved in water, they become aqueous acids. The prefix hydro is attached to the root word of the nonmetal and the suffix –ic is added. The word acid becomes the last term.

H₂S (aq)     hydrosulfuric acid

HCl (aq)    hydrochloric acid

2.       Tertiary/ ternary/ oxyacids

·         -ite – ous acid     phosphorous acid (H₃PO₃)

·         -ate – ic acid       Sulfuric acid (H₂SO₄)

E.       Bases –(OH)

Fe(OH)₂  - ferrous hydroxide

Mn(OH)₃ – manganic hydroxide

Sn(OH)₂ – Tin (II) hydroxide

Writing Chemical Equations

Writing Chemical Equations

Chemical equation

·         The chemist’s shorthand for describing the course of chemical reaction.

Basic terms and symbols:

1.       Reactants – the substance that undergoes change in a chemical reaction. They are always written on the left

2.       Products – the substance produced in a chemical reaction. They are always written on the right.

3.       (g) – for gas

4.       (l) – for liquid

5.       (S) – for solid substances

6.       (aq) – for a substance in water solution

                                  Heat

·         Mercury (III) oxide   --------->   mercury and oxygen

HgO   --------->   Hg  + O₂

Chemical Reaction is  the process by which chemical change takes place.

Types of Chemical Reactions

1.       Syntheses/ Combination reaction

A + B   --------->   AB

Examples:

CuS + S  ---------> CuS

MgO + H₂O ------->  Mg(OH)₂

2.       Analysis/ Decomposition reaction

AB   --------->   A + B

Examples:

H₂O   --------->   H₂ + O₂

KClO₃   --------->   KCl + O₂

3.       Single replacement/ substitution

AX + B   --------->   BX + A

AX + Y   --------->   AY + X

Examples:

KI + Cl₂   --------->   KCl + I₂

Mg + H₂SO₄   --------->   MgSO₄ + H₂

4.       Double Replacement / metathesis

AX + BY   --------->   AY + BX

Examples:

AgNO₃ + FeCl₃   --------->   AgCl + Fe (NO₃)₃

 

Balancing Equations:  

Consider the following equation:

N₂ + H₂   --------->   NH₃

Steps:

1.       Count the number of atoms of each element on the reactant side and product side.

Element                Reactant                      Product

N                              2                                  1

H                              2                                  3

2.       Find out which atoms are unbalanced.

3.       Now balance each element at a time. Do this by placing a small whole number called coefficient in front of symbols or formulas.

N₂ + 3H₂   --------->   2NH₃

4.       Check if the equation is completely balanced.

Element                 Reactant                     Product

N                              2                                   2

H                              6                                   6

Exercises:

Classify the following equations ant then balance.

1.       C₃H₈ + O₂   --------->   CO₂ + H₂O

2.       Ca (ClO₃)₂   --------->   CaCl₂ + O₂

3.       FeCl₃ + Ca (OH)₂   --------->   CaCl₂ + Fe (OH)₃

4.       Hg (NO₃)₂ +Mg   --------->   Mg (NO₃)₂  + Hg

Laws of Nature

Laws of Nature

The "Laws of Nature" are neither matter nor energy - they are the phenomena that control the action and interaction of all matter and energy in the universe. They are universally invariant, conditions may change but the "Laws" never vary. When the "Laws of Nature" came into existence the universe came into existence, they created the universe and determined its size - where the "Laws" end, the universe ends.

The concept of the “Laws of Nature” and “Universal Space” is the same. Nothing can exist beyond their domain, not even space. They are the framework of the universe that gives the universe its personality. What would the universe be like without inertia or gravity, etc... They create the personality of the universe.

Universal space has no structure, it is all one, and there is no unique part of space. Space (the "laws of nature") may or may not be expanding. If they are expanding this could account for the "red shift" of the galaxies. If space is not expanding, the galaxies are simply falling toward the outer boundary of a finite universe; this would also explain the "red shift" of the galaxies.

Nothing moves - relative to space itself. The planet Earth (and everything else in the universe) is stationary - relative to universal space itself. (This should soon be borne out when the results of "Gravity Probe B" are fully analyzed.) The "energy level" of matter - relative to space - determines a body's inertial mass.