Question

state the meaning of land in economies. what does it include? ​

Thoda bda hona chahiye ​

Answer 1

Answer:

Land, In economics, the resource that encompasses the natural resources used in production. ... Land was considered to be the “original and inexhaustible gift of nature.” In modern economics, it is broadly defined to include all that nature provides, including minerals, forest products, and water and land resources.

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Answer 2

Answer:

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A chemical substance that changes the rate of chemical reaction without undergoing any permanent changes during the course of the chemical reaction is said to be a catalyst. The process through which a catalyst changes the rate of chemical reaction is said to be catalysis. Catalyst either increases or decreases the rate of chemical reaction. Catalysts are of two types: Positive Catalyst and Negative Catalyst.

Positive catalyst is defined as the catalyst which increases the rate of chemical reaction. For example: Manganese dioxide (MnO2), a positive catalyst increases the rate of decomposition of hydrogen peroxide.

2H2O2 −→−−MnO2 2H2O + O2 ↑

Negative catalyst is defined as the catalyst which decreases the rate of chemical reaction. For example: Glycerin [C3H5(OH)3], a negative catalyst that decreases the rate of decomposition of hydrogen peroxide into water and oxygen.

2H2O2 −→−−−−−−C­3H5(OH)3 2H­2O + O2

Properties of Catalyst

Catalyst does not change in its mass and chemical composition during the chemical reaction.

Catalyst can be in a small quantity.

Catalyst changes the rate of chemical reaction but does not initiate the chemical reaction.

Endothermic Reaction and Exothermic Reaction

Endothermic reaction is the reaction in which heat energy present in the surrounding is absorbed. The compounds which are formed by the absorption of heat from the surrounding are called endothermic compounds. For example:

CaCO3 + heat → CaO + CO2 ↑

2KClO3 + heat → 2KCl + 3O2 ↑

N2 + O2 + heat → 2NO (Nitric Oxide)

Exothermic reaction is the reaction in which heat energy is released in the surrounding. The compounds that are formed by exothermic reactions are said to be exothermic compounds. For Example:

C(s) + O2(g) → CO2(g) + heat

2H2(g) + O2(g) → 2H2O(l) + heat

CaO(s) + H2O(l) → Ca(OH)2 (aq) slaked lime + large amount of heat

Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g) + heat

Word equation:

The chemical reaction which is expressed in terms of the word (name of reactants and products) is called word equation. For example:

Sodium + Chlorine ⟶ Sodium Chloride

Formula equation:

The chemical equation which is written in terms of symbols by writing their molecular formula is called formula equation. It is of two types:

Skeletal equation: The formula equation in which the number of ions, radicals, atoms etc. in reactant and product side is not equal then it is called skeletal equation. It is also sometimes called unbalanced equation.

chemical-equation

The above equation is skeletal equation as the number of one oxygen atom in reactant and product sides are not equal.

Balanced equation: The formula equation in which the number of atoms, radicals, ions, etc is made equal in both reactant and product side is called a balanced equation. For example:

ANd9GcRlxYGII4d26PvgLO-O5Z_QIXV0O4NrcQ8NnBZiymr6nzILTSxf

Above equation is now a balanced equation because the number of oxygen is made equal in both reactant and product by keeping the suitable number.

Balancing a chemical equation

An unbalanced chemical equation can be converted into a balanced equation by using the following steps:

Step 1: Write the word equation.

Potassium chlorate ⟶Heat Potassium chloride + oxygen

Step 2: Convert the word equation into formula equation.

KClO3⟶ΔKCl +O2

Step 3: Count the number of atoms, ions, etc of the reactant and product and make them equal by using the suitable number in front of them.

2KClO3 ⟶Δ 2KCl +3O2

Information conveyed by balanced chemical equations

It gives symbols, name and the molecular formula of the chemical substances involved as reactants and products.

It gives the relative number of atoms and molecules of reactants that take part in the chemical reaction.

It gives the relative number of atoms and molecules of products formed in the reaction.

It gives the ratio of masses of reactants and products.

It shows the type of chemical reaction.

Limitations of balanced chemical equations

The physical states of reactants and products are not known.

The concentration of reactants and products, in the end, is not known.

The rate of chemical reaction and the time taken for its completion is not known.

The conditions under which chemical reaction takes place is not known.

Whether the heat is released or absorbed during the reaction is not known.

Some reactions may be explosive. It is not revealed by the chemical equation.

Whether the reaction is reversible or not