Chemical Changes and Reactions

Flashcards about chemical reactions and changes.

What is a chemical reaction?

The process of breaking chemical bonds of reactants and making new bonds to form products.

What conditions are necessary for a chemical change?

Mixing (close contact), solution, heat, light, electricity, pressure, catalyst.

What is a chemical bond?

The force that holds atoms of a molecule together.

What is effervescence?

Formation of gas bubbles in a liquid during a reaction.

What is a precipitate?

An insoluble solid substance formed during a chemical reaction.

What is a direct combination reaction?

A reaction where two or more substances combine to form a single substance.

What is a decomposition reaction?

Breaking up of a compound into elements or simpler compounds.

What is thermal decomposition?

Decomposition caused by heat.

What is a displacement reaction?

A reaction where a more active element replaces a less active one in a compound .

What is a double decomposition reaction?

Reaction where two compounds react to form two new compounds by exchanging radicals.

What is a precipitation reaction?

A double decomposition reaction that forms an insoluble salt.

What is a neutralization reaction?

Reaction between an acid and a base to form salt and water.

What is hydrolysis?

Reaction where salt and water react to form an acidic or basic solution.

What is an exothermic reaction?

A chemical reaction in which heat is given out during the process.

What is an endothermic reaction?

A chemical reaction in which heat is absorbed during the process.

What is a photochemical reaction?

Reaction that occurs with the absorption of light energy.

What is an electrochemical reaction?

Reaction that occurs with the absorption of electrical energy.

What does a positive catalyst do?

Accelerates a reaction.

What does a negative catalyst do?

Retards a reaction.

What do promoters do?

Improve the efficiency of a catalyst.

What is an evolution of gas?

The formation of gas during a chemical reaction

What is a change of color?

A change in the color of the reactants during a chemical reaction.

What is change of state?

A change of state of the reactants during a chemical reaction.

What happens in a direct combination reaction?

Two elements combine to form a compound.

What happens in a direct combination reaction?

An element and a compound combine to give a new compound.

What happens in a direct combination reaction?

Two or more compounds combine to form a single product.

Give an example of Evolution of gas.

Zinc and dilute sulphuric acid results to zinc sulphate and hydrogen gas.

Give an example of color change in a reaction

Iron into blue copper sulfate solution leads to green ferrous sulfate.

Give an example of precipitate formation

Silver nitrate into sodium chloride produces silver chloride(white precipitate) with NaNO3 solution.

Give an example of reaction with state change

Ammonia gas and hydrogen chloride gas to produce solid ammonium chloride.

Give an example of direct combination.

Carbon burns in oxygen to form carbon dioxide.

Give an example of Decomposition.

Mercuric oxide decomposes into mercury and oxygen.

Give an example of Decomposition.

Potassium nitrate decomposes into potassium nitrite and oxygen.

Give an example of Thermal Decomposition

Calcium carbonate decomposes into calcium oxide and carbon dioxide.

Metal activities

Zinc is more active than copper.

Non-metal activities

Chlorine is more active than iodine.

What are reversible reactions?

Reactions that can be reversed by changing conditions.

How do chemical reactions change the potential energy between substances?

Breaking and forming bonds.

Manganese dioxide positive catalyst

Increase the rate of decomposition of hydrogen peroxide.

Products of heating Mercuric Oxide.

Mercury + Oxygen.

Reactants that formulate effervescence, brining a pop sound from flame.

Dilute sulphuric acid, and magnesium ribbon.

Foods that undergo decomposition in body.

Starch, Proteins, Fats.

Gases released from heating crystals of lead nitrate.

Nitrogen dioxide and Oxygen

What occurs when heating zinc carbonate?

Lime water turns milky.

What is required if the soil is acidic?

Neutralized it

What occurs to salts regarding the process of Hydrolysis?

Strong base and weak acid, strong acid and weak base.

What does catalyst do?

Changes the rate of a chemical change.

The most reactive element.

Potassium, Sodium

Iron (III) chloride.

Acid.

What is required to formulate ammonia.

High temperature and catalyst.