## Percent Composition and Empirical Formula Practice Problems

In the previous post, we talked about the percent composition and its use for determining the empirical and molecular formulas of compounds. Remember, the percentage composition shows the amount of each element in a compound expressed as a mass percent … Read more

## How To Convert Grams To Number of Atoms

In the previous two posts, we discussed converting grams to moles and grams to molecules. For the moles, here is what we do: first look up the molar mass in the periodic table, set up the correct conversion factor, and … Read more

## Grams to Molecules and Molecules to Mass

In the previous post, we discussed converting grams to moles. Remember, the first thing was to look up the molar mass in the periodic table, set up the correct conversion factor, and finally do the multiplication. Here is a short … Read more

## How To Convert Grams To Moles

To convert the grams to moles, we need to know the molar mass of the substance. Remember, molar mass (M) is the mass of one mole of atoms/molecules/ions expressed in g/mol. To calculate it we are always going to need a … Read more

## Writing Chemical Formulas For Ionic Compounds

Some Patterns of Ions To write the name of an ionic compound based on its name, we first need to remember the valency and the names of the common ions. Let’s start with the alkali and alkaline earth metals. These … Read more

## Calculating The Percent Abundance of Each Isotope

In the previous post, we have seen that the average atomic mass is calculated by the weighted average of the atomic masses of all the isotopes. The formula we can use for this calculation can be written as:   Average … Read more

## How To Calculate The Average Atomic Mass

In the previous post, when talking about isotopes, we mentioned that the mass given for elements in the preperiodic table is not a whole number. For example, the mass of potassium is given as 39.098, and this is because that … Read more

## What Are Isotopes?

Isotopes are atoms of the same element that have the same atomic number but different mass numbers. Now, because the atomic number represents the number of protons, we can also say that isotopes have the same number of protons but … Read more

## How To Calculate The Number of Protons, Neutrons, and Electrons

Before we start with some examples of calculating the number of protons, neutrons, and electrons, let’s recall what information we get about a particular element from the periodic table. For example, if we look up potassium, K in the periodic … Read more

## Mass, Moles, and Number of Particles Practice

In this set of practice problems, we will work on molar calculations such as converting between Mass, Moles, and Number of Ions and Atoms. For all the problems, calculating the molar mass is not shown as it should be a … Read more