## Oxidation State Practice Problems

In the previous post, we talked about the oxidation state and the rules for their determination. In short, you need to know, or have the table, for the standard oxidation states, and determine the unknowns.     Keep in mind, … Read more

## Oxidizing and Reducing Agents

In any oxidation-reduction reaction, there is an oxidizing agent and a reducing agent as oxidation cannot occur with reduction and vice versa, reduction cannot occur without oxidation. The oxidizing agent takes electron(s) from the reducing agent, so we can also … Read more

In the previous post, we talked about atomic radii, and discussed the following periodic trends: Atomic radius decreases across the periodic table to the right. Atomic radius increases down a group in the periodic table.     Radii of Cations … Read more

In a general definition, radius is a straight line from the center to the circumference of a circle or sphere. So, how do we define the atomic radius? The center of the atom is the nucleus, and we consider the … Read more

## Effective Nuclear Charge

Effective nuclear charge (Zeff) is the nuclear charge an electron actually experiences. Let’s understand what this statement means. We know from basic physics that opposite electrical charges attract, and if we consider the hydrogen atom, it is fairly straightforward to … Read more

## Heat and Phase Change Diagrams

In the previous post, we talked about Heat Capacity and Specific Heat. The formula we use to calculate the heat transferred between the objects is given as:     By using this formula, we were able to calculate, for example, … Read more

## P4O10 Oxidation Numbers

To determine the oxidation number of an atom(s) in a molecule or an ion, start with the known oxidation numbers and the rules summarized below:     Keep in mind that the summary is zero for neutral molecules and is equal to … Read more

## H+ Concentration from pH

We have learned that the pH is calculated by the following formula: To calculate the concentration of H+ or H3O+ hydronium ion from pH, we take the antilog of the pH, that is 10 to the negative power of pH. … Read more

## Calculating the pH of 0.10 M NH4Cl

Ammonium chloride (NH4Cl) is the salt of a weak base ammonia (NH3) and a strong acid HCl, so it yields an acidic solution.   NH3 + HCl → NH4Cl   So, let’s follow what we have discussed earlier and see … Read more

## Calculating the Ka for a Weak Acid

Determine the ionization constant (Ka) of a weak acid if its 0.520 M solution has a pH of 2.40. The plan is to determine the [H+] from the pH and use it to determine the equilibrium concentrations of HA and A–. … Read more