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Using Lindlar's catalyst results in syn addition to form a cis alkene. Using lithium in liquid ammonia yields a trans alkene Ozonolysis Preparation of alkynes

Adding HBr to a diene forms a 1-2 adduct (top) or a 1-4 adduct (bottom) Adding Br2 to a diene forms a 1-2 adduct (top) or a 1-4 adduct (bottom)

Creates a vicinal halide (anti addition) syn addition Creates an alkyl halide following Markovnikov's ru Creates a Markovnikov alcohol Creates an anti-Markovnikov alcohol Alkenes react with peracides to form epoxodies/oxiranes through a syn addition Yields two carbonyl compounds. React with cold potassium permanganate to form vicinal diols through a syn addition. Eliminates water to form the most stable alkene (use Zaitsev's rule) Eliminates HX to form the most stable alkene (anti elimination) (use Zaitsev's rule)

Balancing Redox 4 of 6 Reactions - Balance the Charge Next, balance the charges in each half-reaction so that the reduction half-reaction consumes the same number of electrons as the oxidation half-reaction supplies. This is accomplished by adding electrons to the reactions: 2 I - → I 2 + 2e - 5 e - + 8 H + + MnO 4 - → Mn 2+ + 4 H 2 O Now multiple the oxidations numbers so that the two half-reactions will have the same number of electrons and can cancel each other out: 5(2I - → I 2 +2e - ) 2(5e - + 8H + + MnO 4 - → Mn 2+ + 4H 2 O) Balancing Redox 5 of 6 Reactions - Add the Half-Reactions Now add the two half-reactions: 10 I - → 5 I 2 + 10 e - 16 H + + 2 MnO 4 - + 10 e - → 2 Mn 2+ + 8 H 2 O This yields the following final equation: 10 I - + 10 e - + 16 H + + 2 MnO 4 - → 5 I 2 + 2 Mn 2+ + 10 e - + 8 H 2 O Get the overall equation by canceling out the electrons and H 2 O, H + , and OH - that may appear on both sides of the equation: 10 I - + 16 H + ...

Balancing Redox Reactions 1 of 6- Half-Reaction Method To balance redox reactions , assign oxidation numbers to the reactants and products to determine how many moles of each species are needed to conserve mass and charge. First, separate the equation into two half-reactions, the oxidation portion and the reduction portion. This is called the half-reaction method of balancing redox reactions or the ion-electron method . Each half-reaction is balanced separately and then the equations are added together to give a balanced overall reaction. We want the net charge and number of ions to be equal on both sides of the final balanced equation. For this example, let's consider a redox reaction between KMnO 4 and HI in an acidic solution: MnO 4 - + I - → I 2 + Mn 2+ Balancing Redox Reactions 2 of 6- Separate the Reactions Separate the two half reactions: I - → I 2 MnO 4 - → Mn 2+ Balancing Redox 3 of 6Reactions - Balance the Atoms To balance the atoms of each half-r...

Virtual Chemistry Text Table of Contents Oxidation and reduction reactions go hand in hand, which is why they are also called redox reactions. Acids and bases may be thought of as reactions involving hydrogen, or protons, while redox reactions tend to be concerned with electron gain and loss.

Three-Dimensional Arrangement of Atoms in a Molecule There are two electron pairs around the central atom in a molecule with linear molecular geometry, 2 bonding electron pairs and 0 lone pairs. The ideal bond angle is 180°. Ben Mills Molecular geometry or molecular structure is the three-dimensional arrangement of atoms within a molecule. It is important to be able to predict and understand the molecular structure of a molecule because many of the properties of a substance are determined by its geometry. The Valence Shell, Bonding Pairs, and VSEPR Model The outermost electrons of an atom are its valence electrons. The valence electrons are the electrons that are most often involved in forming bonds and making molecules. Pairs of electrons are shared between atoms in a molecule and hold the atoms together. These pairs are called "bonding pairs". One way to predict the way electrons within atoms will repel each other is to apply the VSEPR (valence-shell electron-pair ...