Chemical reactions and Equations long 1 Flashcards
What is a balanced equation ?
The total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the elements present in the reactants.
What are the 5 kinds of reactions and describe them ?
/ Combination reaction - a reaction in which a single product is formed from two or more reactants is known as a combination reaction.
/ Decomposition reaction - In this reaction you can observe that a single reactant breaks down to give simpler products. This is a decomposition reaction.
/ Displacement reaction - In this reaction 1 element has displaced or removed another element from its solution. This reaction is known as displacement reaction
/ Double displacement reaction - Reactions in which there is an exchange of ions between the reactants are called double displacement reactions.
/ Redox reaction - If a substance gains oxygen during a reaction, it is said to be oxidized. If a substance loses oxygen during a reaction, it is said to be reduced. Such reactions are called Redox reactions
What is used for whitewashing and give the formula ?
Slaked lime is used. Calcium hydroxide reacts slowly with the carbon dioxide in air to form a thin
layer of calcium carbonate on the walls. Calcium carbonate is formed after two to three days of whitewashing and gives a shiny finish to the walls.
Formula - Ca(OH)2 + CO2 → CaCO3 + H2O
