Question

D. Answer in brief.
1 What is an element?
2. Define an atom and a molecule.
3. What is the formula of nitric acid? Name the
atoms present in one molecule of nitric acid.
4. Compound A reacts with another
compound B to form a compound C. What
kind of change does this represent?
5. What compounds do these formulae
represent? H,O, CO2, CuSO,, NaHCO3.
6. What is crystallisation? What is it used for?
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Answer 1

Answer:

PLEASE MARK IT AS THE BRAINLIEST

Explanation:

1) an element is a pure substance which cannot be broken down by chemical means, consisting of atoms which have identical numbers of protons in their atomic nuclei. The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number.

2)Atoms are the basic units of matter and the defining structure of elements

Molecule, a group of two or more atoms that form the smallest identifiable unit into which a pure substance can be divided and still retain the composition and chemical properties of that substance.

3) Formula of Nitric acid is HNO₃

The names of the atoms present in one molecule of Nitric acid are

• Hydrogen
• Nitrogen
• Oxygen

4) Combination Reaction

• H= Hydrogen
• O= Oxygen
• CO2= Carbon Di Oxide
• CuSo= Copper Sulphate
• NaHCO3= Sodium Bi Carbonate

6) Crystallization or crystallisation is the process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal. Some of the ways by which crystals form are precipitating from a solution, freezing, or more rarely deposition directly from a gas.

Crystallization is used in the chemistry laboratory as a purification technique for solids. An impure solid is completely dissolved in a minimal amount of hot, boiling solvent, and the hot solution is allowed to slowly cool.