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Atoms And Molecules
Question
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Give an illustration based on atomic theory for the difference between an element, compound and mixture.

Answer

Characteristic

Compound

Element

Define

A compound contains atoms of different together in a fixed ratio.

An element is a pure chemical substance made of the same type of atom

Distinguishing features

Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds.

Elements are distinguished by their atomic number (number of protons in their nucleus).

Ability to breakdown

A compounds can be separated into the simpler substance by chemical method reaction only.

A element cannot be broken down into the simpler substance by chemical reactions.

Types

The list of compounds is endless.

There are about 117 elements that have observed, can be classified as metal, non-metal or metalloid.

Representation

A compound is represented by using formula.

An element is represented by using symbols

Examples

Water (H2O), sodium chloride (NaCl), sodium bicarbonate (NaHCO3) etc.

Iron (Fe), silver (Ag), gold (Au), nickel (Ni) etc.

Sponsor Area

Some More Questions From Atoms And Molecules Chapter

Convert into mole

(a) 12 gm of oxygen gas

(b) 20 gm of water

(c) 22 gm of carbon dioxide.

What is the mass of?

(a) 0.2 mole oxygen atoms.

(b) 0.5 mole of water molecules.

Calculate the number of molecules of sulphur (S8) present in 16 gm of solid sulphur.

Calculate the number of aluminium ions present in 0.56 gm of aluminium oxide.

Explain law of conservation of mass.

50 g of 10% lead nitrate is mixed with 50 g of 10% sodium chloride in a closed vessel. After the reaction has taken place, it was found that 6.83 g of lead chloride was precipitated. Besides, the reaction mixture contained 90 g water and sodium nitrate. Calculate the amount of sodium nitrate formed.

Name and explain two important laws of chemical combination ?

What are the postulates of Dalton’s atomic theory of matter?

Hydrogen and oxygen combine in two different ways to produce water and hydrogen peroxide. Which of Dalton’s law does this observation confirm? Explain.