Carboxylic Acids

Primary Amines

Haloalkanes

Haloalkanes are a very useful intermediate compound, often used when converting one useful compound into another. Their own uses are limited, primarily due to the impact they have on the environment. Haloalkanes are generally immiscible (insoluble in water) as they are (technically) non-polar.

Haloalkanes are the products of:

• reacting a halogen (such as bromine) with hydrocarbons.
• reacting an alcohol with Lucas Reagent (chloroalkanes produced); remember that tertiary alcohols react very quickly, while primary alcohols may not react at all.
• reacting an alcohol with PCl₃, PCl₅ or SOCl₂

Haloalkanes can be converted into:

• alkenes, using NaOH (or KOH) dissolved in alcohol (elimination reaction)
• alcohols, using aqueous NaOH (or KOH) (substitution reaction)
• amines, using excess NH₃ (substitution reaction); if you use do not use enough NH₃, it will make an amino salt instead, such as ethyl ammonium chloride

For more information about haloalkanes, click HERE (ChemGuide)

Alcohols

INTRODUCTION

The structure of alcohols tells us a lot about their physical properties and chemical reactions. Last year, the first lesson was about the different isomers of C₄H₉OH, with the students starting by trying to make (and name) all of the ones that contain the alcohol functional group. Can you name these?

PREPARATION

There are a few ways to make alcohols:

• fermentation of sugars
• synthesis gas
• hydration of alkenes

We looked at the hydration of 1-butene using dilute sulfuric acid:

REACTIONS

In this topic, we will do some experiments with primary, secondary and tertiary alcohols. Here are some videos explaining some of the expected observations and how to use them to identify/classify alcohols.

Reactions of Alkenes

Hydrocarbons - Alkanes vs. Alkenes

Today's lesson was based upon an experiment where the properties and reactions of cyclohexane and cyclohexene were compared and contrasted:

Hydrocarbons - Alkenes (1)

This lesson is the first one about Alkenes:

• isomerism (including geometric isomers)
• naming (including cis and trans, when applicable)

2013 Video

2014 Video

2015 Video

Reactions of Alkanes

Today we looked at some of the physical and chemical properties of alkanes. Honestly, this is not very exciting, but it is useful to know these properties and reactions for the latter part of this unit.

Hydrocarbons - Alkanes

Today we looked at the alkanes:

• "functional group" - not really relevant for this homologous group
• general structure
• naming
• isomerism

The videos being posted in this blog will be from previous years while Mrs Goodman teaches us.

2015 blog

2014 blog

Equilibrium Constant

le Chatelier's Principle

Calculating pH

Acidic or Alkaline?

Acids and Bases Overview

We went over what we remember from last year, and where this topic will lead us. There were links made with physical properties, such as electrical conductivity, and chemical properties such as pH and reaction rates, for strong vs. weak acids.

Collision Theory

This was a recap of the Collision Theory. We need to apply it to changes in conditions and reaction rates. This will be done over the next few lessons.

Redox Overview

AUTO-OXIDATION

Some species can act as oxidants and reductants. In special cases, this means the species can decompose itself: auto-oxidation.

KEY CONCEPTS

EQUATIONS

Oxidation Numbers

A quicker way to justify that redox has occurred is to assign atoms their oxidation numbers. If the oxidation number has changed, it is redox:

Redox Half Equations

One of the most important skills we need to have is to write half equations. Once we know which species is being oxidised (or reduced) and which species it has become, we can start to build a half equation using some useful steps/rules:

The following videos are overviews of oxidation and reduction but also include how to write balanced half equations from about the 4-minute mark:

Practical Redox

The following video shows the results of a couple of our experiments for today:

For each reaction:

1. Identify the redox pairs. For example, Permanganate ions and Manganese ions are a pair.
2. Write the half equations for each redox pair.
3. Combine the half equations to give an overall (net) equation.
4. Use oxidation numbers to justify that these are indeed redox reactions. In the first experiment, focus on the oxidation numbers of manganese and iron. In the second experiment, look at the oxidation number of chromium.

Oxidation Reduction Intro

We were introduced to a special type of reaction: Oxidation-Reduction (Redox). What are these reactions? How do we tell if a reaction is redox?

Here are some key terms that we discussed. Understanding and being able to use these terms will help us in the upcoming Achievement Standard assessment tasks.

Calculating Enthalpy Change from Experimental Results

We looked at two possible ways. They are different, depending upon the data you have been given.

Using a Standard Solution

• Precisely known concentration
• Precisely known volume (therefore, known mass as well)
• Known temperature change

Using a Pure Solid

• Precisely known mass of solid
• Known mass of solution
• Known temperature change

Bond Energies

To try and bring everything together, we have to decide if some common reactions/changes are exothermic or endothermic and explain how we chose:

Enthalpy Change Graphs

CATALYSTS

LOWER INITIAL TEMPERATURE

HIGHER INITIAL TEMPERATURE

Enthalpy Changes

We did some experiments to show that some reactions release heat energy (observed as a temperature increase) while others absorb heat energy (temperature decrease). This is explained using a concept called enthalpy.

Molecular Polarity

One of the key skills in this unit is to determine whether a molecule is polar or not. Once we know that, we can explain some of its physical and chemical properties.

Molecular Shapes and the VSEPR Theory

Lewis Dot Diagrams

Electronegativity - Covalent or Ionic?

In this part of the topic, we are focusing on Molecular Substances. Before we can start, we need to be able to work out if a substance is molecular or not. Molecular substances contain Covalent Bonds. How do we decide if a substance contains covalent bonds or not?