## Latest Posts

### Properties & Uses of Ammonia & Ammonium Salts

Physical Properties of Ammonia Colourless gas with pungent choking smellAlkaline gas (turns damp red limus paper blue)Less dense than airVery soluble in water Tests For Ammonia You can test for the presence of ammonia with the two tests below: Test 1 Hold a damp red limus paper into unknown gas. If the litmus paper turns blue, then the gas is…

### Manufacturing Ammonia

Haber Process Ammonia ($\text{NH}_{3}$) is manufactured from nitrogen and hydrogen by the Haber process (which is a reversible reaction). Starting Ingredients – Nitrogen & Hydrogen Nitrogen is obtained from the fractional distillation of liquid air. Hydrogen is obtained from steam reforming of natural gas: $\text{CH}_{4}(\text{g}) + 2\text{H}_{2}\text{O}(\text{g}) \rightarrow \text{CO}_{2}(\text{g})+4\text{H}_{2}(\text{g})$ cracking of petroleum fractions: $\text{C}_{2}\text{H}_{6}(\text{g}) \rightarrow \text{C}_{2}\text{H}_{4}(\text{g}) + \text{H}_{2}(\text{g})$ Equation of…

### Reversible Reaction

A reversible reaction ($\rightleftharpoons$) is a reaction that can take place in both directions – i.e. forward reaction and backward reaction. When the rate of forward reaction is equal to the rate of backward reaction, the reaction is said to have reached a state of dynamic equilibrium. When a chemical reaction reaches a state of dynamic equilibrium: the rate of…

### Preparation of Soluble Salts & Insoluble Salts

Preparation of Soluble Salts The methods of preparing soluble salts are categorised into: Solution + Solid Solution + Solution Solution + Solid In the “solution + solid” method, a solid and solution are reacted together to form soluble salt. You may follow the following procedures to prepare soluble salts: Add solid, a little at a time into warm solution. Stir….

### Salts

A salt is an ionic compound formed when the hydrogen atom in an acid is replaced by a metal ion or ammonium ion. Note: Please do not restrict your thinking/interpretation of “salt” to the normal “table salt” in your kitchen. Neutralization is one common reaction whereby a salt is produced. An acid reacts with a base (neutralization reaction) to produce…

### Oxides

Elements react with oxygen (aka. burn in oxygen) in the atmosphere to form oxides. Oxides are classified as: Acidic Basic Amphoteric Neutral   Acidic Oxides Acidic oxides react with water to form acids. Recall: Solutions of these acids in water have a pH value of less than 7. Acidic oxides are oxides of non-metals, which is also known as non-metallic…

### pH Scale & Indicators

The pH scale (as shown in the figure above) is used to measure the acidity or alkalinity of an aqueous solution. The pH scale is numbered between 0 to 14. For reference, the equation for pH is given by: $$\text{pH} =-\text{lg} [\text{H}^{+}]$$ pH is given by the negative logarithm of the concentration of hydrogen ions ($[\text{H}^{+}]$). You can see that…