Question

1. What is a catalyst? What are the two types of catalysts? Give one example of each.
Define the following with one suitable example.
Exothermic reaction
b. Endothermic reaction
3. What is a chemical reaction? How is it represented? Explain with an example.
What are the characteristics of a chemical reaction? Make a list of them. Give one example each
5. Explain with two examples where chemical reaction leads to formation of precipitate.
6. What are the two most essential conditions for a chemical reaction to take place? Give one
example of each.​

Answer 1

Answer:

1 Types of catalytic reactions

Catalysts can be divided into two main types - heterogeneous and homogeneous. In a heterogeneous reaction, the catalyst is in a different phase from the reactants. In a homogeneous reaction, the catalyst is in the same phase as the reactants

2 In simple terms, the endothermic reactions absorb energy from the surrounding that is in the form of heat. On the other hand, an exothermic reaction releases energy into the surrounding of the system. A popular example of an endothermic chemical reaction is photosynthesis.

3 A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another.[1] Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking of chemical bonds between atoms, with no change to the nuclei (no change to the elements present), and can often be described by a chemical equation. Nuclear chemistry is a sub-discipline of chemistry that involves the chemical reactions of unstable and radioactive elements where both electronic and nuclear changes can occur.

The substance (or substances) initially involved in a chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Reactions often consist of a sequence of individual sub-steps, the so-called elementary reactions, and the information on the precise course of action is part of the reaction mechanism. Chemical reactions are described with chemical equations, which symbolically present the starting materials, end products, and sometimes intermediate products and reaction conditions.

5 Examples Of Precipitation Reaction In Everyday Life

In waste water, a frequent presence of heavy metals can be found such as compounds of sulphide and hydroxide. So, we can add a source of hydroxide that is soluble (NaOH Or Na2S) that will result in precipitation reaction.

6 Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. Some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. Understanding chemical changes is a major part of the science of chemistry.

When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an energy change as new products are generated. An example of a chemical change is the reaction between sodium and water to produce sodium hydroxide and hydrogen. So much energy is released that the hydrogen gas released spontaneously burns in the air. This is an example of a chemical change because the end products are chemically different from the substances before the chemical reaction.

Answer 2

Explanation:

1. Catalyst is a substance that increase the rate of a chemical reaction without itself undergoing in chemical change

2.. (a). EXOTHERMIC REACTION: IN THIS REACTION heat is released ...

eg.. combustion: CH4+2CO2=== CO2+2H2O

(b).. ENDOTHERMIC REACTION : in this reaction heat is absorbed...

eg.. Formation of Gulcose

6CO2 + 6H2O.heat===== C6 H12 O6 + 6O2

3.. THE process in which one or more substance ,the reactant are converted to one or more different substance..

• EVOLUTION OF GAS
• FORMATION OF PRECIPITATE
• CHANGE IN COLOUR
• CHANGE IN TEMPERATURE
• CHANGE IN STATE