# Avogadro’s Law: History and Work Problem

Learn about Amedeo Avogadro and his funky gases, Italian Revolutions, and starry-nosed moles.

# Charles’s Law: History and Work Problem

And we're back for the second installment of our gas laws series - Charles' Law. If you need to refresh on the other gas laws in this series you can check out our post on Boyles' Law, Avogadros' Law, and the Ideal Gas Law. Let's review what a gas is: a gas a is a … Continue reading Charles’s Law: History and Work Problem

# Boyle’s Law: History and Work Problem

The two variables we're looking at today are pressure and volume, whose gas relationship was discovered during the Renaissance.

# Work Problem: Light and Photons

What we often refer to as 'light' is a narrow portion of a broad spectrum of electromagnetic radiation. This spectrum stretches from radio waves with a wavelength of 10³ m to gamma rays with a wavelength of 10⁻¹² m. We work mainly with light in the visible spectrum in this lesson, but the fundamentals learned here can be applied to any portion of the EM spectrum.

# Practice Problem: Gibbs Free Energy

Given Question: The reaction given above is accompanied by the Enthalpy of the reaction (H) and the entropy (S). Determine the change in Gibbs Free energy (G) and if the reaction is spontaneous or not. If the reaction isn't spontaneous, calculate the temperature in which it will be.  Start off by listing what … Continue reading Practice Problem: Gibbs Free Energy

# Work Problem: Calculation of Molar Mass of Unknown Base Using Titration With a Strong Acid

Given Question: A student titrates 2.0135 grams of an unknown monobase weak base to the equivalence point with 67.02 mL of .5003 M HCl(aq). What is the molar mass of the weak base?  Step 1: This is to sort out what we're given in the equation, as well as some previous knowledge. We'll use the first … Continue reading Work Problem: Calculation of Molar Mass of Unknown Base Using Titration With a Strong Acid

# Determining the Molar Solubility of Iron (II) Hydroxide

Given Question: Calculate the molar solubility of Fe(OH)2 (Ksp=4.87*10^-7).  Tutor's Note: The Ksp radical that's written down comes in later, I got confuzzled by my own notes! Happens to all of us. Sorry students 🙂  Step 1: Write out the reaction equation with all ions. Make sure it's balanced! We'll use this in the next step with … Continue reading Determining the Molar Solubility of Iron (II) Hydroxide

# Determining Precipitate Yield (g) in Aqueous Solution

Given Question: Given the reaction: K3(PO4)+ Ni(SO4)→ K3(SO4)(aq)+Ni(PO4)(s), with 100.0 ml of K3PO4 and 200.0 ml of NiSO4 under standard conditions, how many grams of precipitate form?  Step 1: Determine the limiting reactant and the precipitate.  In order to determine the limiting reactant, one must convert all reactants to moles (mol). In this case, we can … Continue reading Determining Precipitate Yield (g) in Aqueous Solution

# Calculating the pH of a Buffer System

The point of this problem is to correctly calculate the pH of a buffer system using formonitrile, or hydrogen cyanide. Here, we use the dissociation constant and the Henderson-Hasselbach equation. Given Problem: Calculate the pH of a buffer that's .250 M HCN (kª= 4.9*10^-10) and 0.170 M KCN.  2. This is to remind us of the … Continue reading Calculating the pH of a Buffer System

# Titration of Strong Acid With Strong Base

The goal of this example is to help students become fluent in calculating pH/pOH of a solution during a titration of a strong acid (HCl) and a strong base (NaOH). This problem includes calculations for titrations of increasing volumes. Given Problem: Calculate the pH of a titration of 25.0 mL of HCl (.100 M) with … Continue reading Titration of Strong Acid With Strong Base