October 23, 2019

To convert grams to moles and vice versa, we must always use Molar Mass.

Molar Mass can be calculated using the Periodic Table.

To calculate the molar mass, we multiply each atom in the molecule by its atomic mass found in the Periodic Table and multiply by the number of atoms.

For example, to calculate the molar mass of CO2

C= 1*12.011 = 12.011

O= 2*15.999 = 31.998

12.011 + 31.998 = 44.009 g/mol

To convert grams to moles, we...

October 21, 2019

Lactic acid has one acidic hydrogen. A 0.1 M solution of lactic acid has a pH of 2.44. Calculate Ka for lactic acid? When we do acid/base questions, we always need to ask ourselves 2 questions.

Question1 Do we have an acid or a base?

In this case the question itself, told us that we are dealing with an acid.

Question 2 Is this a weak or a strong acid?

Strong acids are: HCl - hydrochloric acid HNO3 - nitric acid H2SO4 - sulf...

October 16, 2019

Will precipitation occur when the following solutions are mixed? If so, write a balanced chemical equation for the reaction.

(a) Na2CO3 and AgNO3, (b) NaNO3 and NiSO4, (c) FeSO4 and Pb(NO3) 2

In order for precipitation occur, we must first write out the products of each reaction. These are double replacement reactions, where we can use the following formula: AB+CD --> AD + CB to predict the products. We also need to remem...

September 25, 2019

How To Name Acids

An acid is a substance that releases H+ ions (hydrogen ions) when it is dissolved in water.

Acids can be divided into 2 categories: binary acids and oxyacids.

Binary Acid - consists of H + nonmetal

Examples of binary acids are HCl, H2S, HBr

Naming a binary acid - HYDRO _____ IC ACID

HCl - hydrochloric acid

H2S - hydrosulfuric acid

Oxoacid - consists of H + Polyatomic ion containing O

Examples of oxoacids are H...

June 24, 2019

How to identify a weak acid?

A weak acid is an acid that does not dissociate completely. If we are given a Ka for an acid that is small, the acid must be weak. For strong acids, Kat are not even usually given, unless the professor is trying to trick you.

There are three definitions of acids:

Arrhenius acid- Hydrogen ion producer when in water.

Bronsted Lowry acid - proton (H+) donor

Lewis acid - electron pair acceptor.

I...

December 4, 2018

What does it mean for a reaction to be spontaneous? It means that the reaction will occur on its own, without any outside energy input needed. It does not mean that this will happen fast. In fact, it could take hundreds of years for a spontaneous reaction to occur.

The way to predict spontaneity is by calculation Gibbs Free Energy or deltaG. When deltaG is negative that means the reaction is spontaneous, and positive me...

November 14, 2018

Many students in their general chemistry classes learn about coordination complexes. Coordination complexes are created when transition metal ions bind to molecules and ions called ligands. . Examples of ligands are: H2O, CN-, NH3, en.

Transition metals have many unique characteristics due to their partially filled d orbitals. These characteristics are: 1.  Transition metals often have more than one stable oxidation sta...

February 25, 2018

First we must write the formula for density. Density = mass/volume Now, let's figure out if we have all of the components for our equation. We do have the weight or mass of  silver metal, 194.3 g. But we need to calculate volume of the metal. We know that initially volume in cylinder was 242 ml and when silver metal was placed in the cylinder, the volume increased to 260.5 ml. Therefore, to find the volume of metal...