fundamental chemistry|Ch#1(part 2)|tutoronlines

Chapter no. 1

Fundamental Chemistry

( part 2 )

Answer these short Question:

Q.No.23. An element with A = 39 Z = 19 calculate the number of electron and proton in one atom of this element?

Ans. Number of protons = 19
number of electrons = no. of proton
= 19

Q.No. 24. Define molecular formula and give example?

Ans. The formula of a compound that represent the real number of atoms of all elements, known as molecular formula.
for example molecular formula of glucose is C6H12O6.

Q.No.25. Name the element reprsented by the given symbols W & Ba?

Ans. W= tungsten , Ba = Barium

Q.No.26. Write the chemical formula of Aluminium sulphate and calcium phosphate.

Ans. Aluminium sulphate: Al2(SO4)3
Calcium phosphate: Ca2(PO4)2

Q.No.27. Describe any two differences between compound and mixture?
Ans. Compound:

It is form by chemical combination of atoms of elements. The constituents lose their identity and form a new substance having entirely different properties.

Mixture:

It is form by combination of different thing. Its component do not lose their properties.

Q.No.28. Define Homogeneous and heterogenous mixture?
Ans. Homogeneous Mixture:

Those mixture which have uniform composition of components. e.g. air, gasoline.

Heterogenous mixture:

Those in which there is unequal distribution of components has been taken place. e.g. wood, rock

Q.No.29. Which gases are present in air? write their names?

Ans. Air is mixture of nitrogen, oxygen, carbon, dioxide, noble gases and moisture.

Q.No.30. What is atomic number? give examples?

Ans. The element of atomic number showa number of proton in a nucleus of atom of element. It’s symbol is Z.
For example the atomic number of hydrogen is 1. because it has one proton in its nucleus.

Q.No.31. Define element and compound?
Ans. Element:

The substance which consists of same type of atoms, having same atomic number. That can not be change into simple substance by mean of chemical methods.

Compound:

It is formed by chemical combination of atoms of element. The constituent lose their identiy and form a new substance having entirely different properties of theme.

Q.No.32. Define element and give two examples?

Ans. A substance, Which contains same type of atoms, having same atomic number, and that can not be decomposed into simple one by chemical means, known as element. e.g Iron, Gold.

Q.No.33. Write the chemical formulas of caustic soda and washing soda?

Ans. Caustic soda = NaOH
Washing soda = Na2CO3

Q.No.34 Define the term anions? Give one example.

Ans. An atom or a group of atoms having negative charge is called anion. e.g Cl- and O2-

Q.No.35. What is the difference between ions and free radicals?

Ans. Difference between ions and free radicals are

Sr. No Ions
Free Radicals
1 Ions are atoms, which bear some charge. There are the atoms that have odd number of electrons.
2 They can exit solution or in crystal lattice. They can exit in solution as well in air.
3 Their formation is not affected by the presence of light. They may form in presence of light.
Q.No.36. Write two different between ion and atom?
Ans. Atom:

Atom is a smallest particle of an element.
It can not exit independently and can take part in chemical reaction.

Ions:

It is a smallest unit of ions compound.
It can not exit independently and is surrounded by oppositely charged ions.

Q.N.o.37. Define molecular ion?

Ans. When one or more electrons escape from a molecules or enter in a molecule, then molecular ion or radicals is formed, e.g sulphate radical.

Q.No.38. What is the difference between molecules and molecular ion?

Ans. Difference between molecules and molecular ion are given below:

Sr. No
Molecule
Molecular ion
1 The smallest particle of an element or compound, which can exit independently, and having the properties of that element or compound. It is form, when an electron related or gained by an element.
2 It is always neutral. It has negative or positive charge.
3 It is formed by combination of an atom. It is formed by ionization of molecules.
Q.No.39. What is meant by cation?

Ans. An atom or group of atoms having positive charge on it is called cation. e.g. sodium (Na+) and potassium (K+)

Q.No.40. Define diatomic molecule and give an example?

Ans. A molecule which contain two atoms is called diatomic molecule. For example, Hydrogen gas (H2)

Q.No.41. How free radicals is formed?

Ans. To form free radical, there is equal distribution of electrons between two atoms. It occurs when these atoms absorb light or energy. Free radical is very reactive.

Q.No.42. Define ion with an example?

Ans. An atom or group of atom having some charge is called ion. e.g. Na+ ion, Cl- ion.

Q.No.43. Define free radical and give example?

Ans. Atom or group of atoms having odd number of electrons. We put a dot (.) on the symbol of atoms to represent it. For example H., Cl.

Q.No.44. Differentiate between Homoatomic and Heteroatomic molecules?
Ans. Homoatomic Molecules:

Those molecules having same type of atoms are called Homoatomic molecules. e.g. hydrogen (H2) , Ozone (O3).

Heteroatomic Molecules:

Those molecules having different types of atoms are called Heteroatomic Molecules. e.g. water (H2O).

Q.No.45. Define Triatomic and Heteroatomic Molecules and give one example to each?
Ans. Triatomic Molecule:

Those molecules having three atoms are called triatomic molecules. e.g. H2O, CO2.

Heteroatomic molecules:

Those molecules having different types of atoms are known as heteroatomic molecules. e.g. H2SO4.

Q.No.46. What is the difference between anions and cations?
Ans. Anion:

Atoms or group of atoms having negative charge is known as anion. e.g. Cl-.

Cations:

Atoms or group of atoms having positive charge is known as cations. e.g. Na+.

Q.No.47. How cations are formed?

Ans. Cations are formed, when an atom remove few electrons from its valence shell. For example Na+ and K+ are cations of sodium and potassium respectively.

Q.No.48. Why and how elements are arrange in a period?

Ans. The element are arrange in a period on the basic of their atomic numbers and electronic configuration to make the study of elements and their compounds easier.

Q.No.49. Differentiate between gram atom and gram molecule?
Ans. Gram atom:

When the atomic mass of an element represents in grams. It is known as gram atom or gram atomic mass.

Gram molecule:

When the molecule mass of compound represent in gram, it is known as gram molecule.

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