LECTURE 5 Flashcards
• Rules in balancing chemical equations
- Adjust the coefficient of ____ last
- Check to see that the atoms of all
elements are balanced
Mono-atomic
• Rules in balancing chemical equations
1. Gaseous elements exist as ____ molecules (e.g. H2, O2, N2, F2, Cl2, Br2, I2)
2. Balance first the elements other than oxygen or hydrogen
- When there are groups of atoms acting as a unit such as a polyatomic ion, it is best to balance them as _____ groups
- Balance hydrogen or oxygen next and select the one that is present in the ___ number of compounds first
Diatomic
Self-contained
Fewer
• Guidelines in balancing chemical equations
1. Subscripts of a compound are ___; they cannot be changed
- The coefficients used should be the smallest whole numbers possible
- The coefficients multiplies every number in the formula
Fixed
– In reactions between two compounds in aqueous solution, the positive and negative
ions appear to “change partners”
Reaction
AX + BY → AY + BX
Double replacement reaction
– Also known as Methathesis Reactions
Double replacement reaction
– Reactions in which one element displaces another from a compound
– More active metals displaces less active metals
Reaction
AB + X → XB + A
where X is more active than A
Single replacement reaction
– Are those reaction in which a compound decomposes to produce the following:
• Two Elements
• One or more elements and or one or more
compounds
• Two or more Compounds
Reaction
AB → A + B
Decomposition reaction
– Reaction in which two or more substances combine to form a compound
• Element + Element — Compound
• Element + Compound—Compound
• Compound + Compound—- Compound
Reaction
A + B → AB
Combination reaction
- • ____
A + B—- AB - _____ Reaction
AB → A + B - _____ Reaction
AB + X → XB + A - _____ Reaction
AX + BY → AY + BX
Combination reaction
Decomposition reaction
Single replacement reaction
Double replacement reaction
– Consists of symbols and formulas
representing a chemical reaction
• ______
– Reacting species written to the left of the arrow
• _____
– Species Formed as a result of the reaction
Chemical equation
Reactants
Products
– Acids formed by combination of hydrogen with most of the polyatomic anions
• Naming Convention
– [Root of the Anion] + [-ic or -ous] + [acid]
– Oxyanion ends that ends with
• –ite change to – ous
• – ate change to –ic
Oxyacids
are acids composed of hydrogen plus another element
Naming Convention
[Hydro] + [Root of the Anion] + [-ic] + [acid]
Binary acids
– The least electronegative element is written first
– The number of atoms of each element is indicated
by the use of Greek Prefixes
Non-metal-non-metal binary compounds
– The name has a root taken from the name of the central atom
e.g. Carbonate CO3²
Nitrate NO3
Chlorate ClO3
-
Polyatomic ion
• Formula that contains more than one of a
group of atoms that occurs as a unit
e.g. Na2CO³ Sodium Carbonate
KMnO⁴ Potassium Permanganate
CaClO² Calcium Chlorite
Polyatomic compounds
Formula Writing & Naming Compounds
To distinguish between compounds with varying
charges
• ____
• [Name metal] (Charge in Roman
Numeral) [non-metal ends with –ide]
• ____
• [Latin name + “ous” or “ic”] ) [non-metal
ends with –ide]
where: ous – lower charge
ic – higher charge
Stock method
Classical method
Formula Writing & Naming Compounds
• Metals with Ions of ____ one charge
– Some representative elements and most transition elements can form more than one cation
e.g. Copper chloride is ambiguous
More than
Guide for Naming Binary Ionic Compound
• _____ Compounds
– [Name of Metal] [Non-Metal ends with -ide]
• Formula writing
– Cross Charge Method
• ____ are used in formulas when atom ratios are ____
Ionic binary
Cross change method
Subscripts
Not 1:1
GUIDE FOR NAMING BINARY IONIC BONDS
• The ____ is always listed before the anion
• The Cation – Anion ratio must give a net charge of ___
• The ratio is always expressed by the ____ whole numbers
• The ____ English name of the metal is used
• The name of the anion includes only the English root plus –____
Cations
Zero
Smallest
Unchanged
Ide
– Composed of just two elements
• Metal Cation + Non Metal Anions
–Example: NaCl, K2S
Metal-nonmetal binary compounds (binary ionic compound)
• Shows the distribution of electrons in the outermost shell of the atom as the atoms are united to each other
Lewis electronic formula
• Represents atoms as lines or bonds to represent valence
Structural formula
• Based on the actual number of atoms that comprise a
molecule of that compound
Molecular formula
• Reflects the simplest ratio of atoms in the compound
Empirical formula
