Chemical Reactions Unit 19 Overview

What is an Alkali?

Base soluble in water producing more hydroxide ions than hydrogen ions.

What is an Acid?

Corrosive substance with pH < 7 due to high hydrogen ion concentration.

What is Activation energy?

Minimum energy required for colliding particles to react.

What is a base in terms of neutralization?

Substance reacting with acid to neutralize it and form a salt.

What is 'Corrosive'?

Capable of damaging metal, stonework, clothes, and skin.

What is a Displacement reaction?

Occurs when a more reactive element replaces a less reactive one in a compound.

Endothermic

Reaction absorbing energy.

Energy level diagram

Chart showing energy in reactants/products and their difference.

Exothermic

Reaction releasing energy to surroundings, increasing temperature.

Indicator

Substance with color change based on solution pH.

What is a Litmus paper?

Indicator turning red in acids and blue in alkalis.

What is Neutral?

Substance with pH of 7, neither acidic nor alkaline.

Explain the process of Neutralization

Make a substance neutral by removing acidic or alkaline properties.

Oxidation

Gain of oxygen or loss of electrons in a chemical reaction.

pH

Scale measuring acidity or alkalinity.

Saturated solution

Solution where no more solute will dissolve.

Soluble

Able to dissolve in a solvent.

Solvent

Liquid in which a solute dissolves to form a solution.

Solution

Mixture where particles are dissolved and carried by the solvent.

Thermal decomposition

Reaction where compound breaks down into two or more substances when heated.

Universal indicator paper

Paper with chemical solution showing different pH levels through color changes.

Solubility

Measure of how much of a substance can dissolve in a given volume of liquid (solvent).

Solubility of gases

Depends on pressure and temperature; generally, gases become less soluble as temperature increases.

Solubility of solids

Refers to how much of a solid substance dissolves in a given amount of liquid solvent.

Precipitate

Insoluble product formed when two solutions react, leading to a precipitation reaction.

Ion Identification Tests

Methods to identify cations and anions in solutions, involving specific reactions and observations.

Transition Metal Hydroxides

Insoluble compounds formed when sodium hydroxide is added to solutions of transition metal ions.

Energy Conservation

Total energy before and after reaction remains constant.

Exothermic Reaction

Energy released to surroundings, increasing temperature.

Endothermic Reaction

Energy absorbed from surroundings, decreasing temperature.

Activation Energy

Minimum energy for particles to react.

Reaction Profile

Shows energy changes in reactants and products.

Internal Energy

Total energy of particles in a substance.

Temperature

Average speed of particles in matter.

Kinetic Energy

Energy of particles in motion.

Chemical Potential Energy

Energy stored in chemical bonds.

Energy Transfer

Movement of energy to or from surroundings.

Reaction Diagram

Illustrates energy changes in a reaction.

Combustion Reaction

Example of exothermic reaction.

Thermal Decomposition

Example of endothermic reaction.

Neutralisation Reaction

Another example of exothermic reaction.

Reaction Temperature

The temperature change when a reaction occurs

Reaction Energy Change

Difference in energy between reactants and products.