Kerala Syllabus Class 9 Chemistry Model Question Paper Set 1 English Medium

Teachers recommend solving Kerala Syllabus 9th Standard Chemistry Question Papers Set 1 to improve time management during exams.

Kerala Syllabus Std 9 Chemistry Model Question Paper Set 1 English Medium

Score :40
Time: 1 1⁄2 hrs.

Instructions

• First 15 minutes is given as cool off time. This time is to be spent for reading and understanding the questions.
• Answer the questions according to the directions.
• Scor e and time to be considered while answering.

I. Answer any four questions from 1-5. Each carries 1 score. (4 × 1 = 4)

Question 1.
Who proposed the planetary model of the atom?
(J.J Thomson, Rutherford, Bohr Dalton)
Answer:
Rutherford

Question 2.
The arrangement of eight electrons in the outermost shell of an atom is called _____
Answer:
Octet configuration

Question 3.
Which is the gas formed when zinc and hydrochloric acid react together?
Answer:
Hydrogen

Question 4.
The group number of noble gases in the modern periodic table is _____
Answer:
18

Question 5.
Mainly, the mass of an atom depends on the mass of (protons and electrons, electrons and neutrons, protons and neutrons, neutrons and electrons)
Answer:
Protons and neutrons

II. Answer any four questions from 6-10. Each carries 2 scores. (4 × 2 = 8)

Question 6.
The atomic number of an atom is 13. Its mass number is 27.
a) Write the number of electrons and neutrons in the atom.
b) Write the electron configuration of this element.
Answer:
a) Number of electrons = 13
Number of neutrons = 27 – 13 = 14
b) 2, 8, 3

Question 7.
Find out the wrong statements from those given below and correct them.
a) Oxidation is the process of gaining electrons.
b) Oxidising agent gets oxidised in a redox reaction.
c) Oxidising agent gains electrons in a redox reaction.
d) Reducing agent gets oxidised in a redox reaction.
Answer:
a) Wrong
Oxidation is the process of losing electrons.
Or
Reduction is the process of gaining electrons.

b) Wrong
The oxidising agent gets reduced in a redox reaction.
Or
The reducing agent gets oxidised in a redox reaction.

Question 8.
The chemical formula of phosphoric acid is H₃PO₄.
a) What is the basicity of phosphoric acid?
b) Which are the ions in phosphoric acid?
Answer:
a) Three
b) H⁺ and \(\mathrm{PO}_4^{3-}\)

Question 9.
Balance the following chemical equations.
1) N₂ + H₂ → NH₃
2) H₂ + O₂ → H₂O
Answer:
1. N₂ +3H₂ → 2NH₃
2. 2H₂ +O₂ → 2H₂O

Question 10.
The electron configuration of some elements is given below.
i) ₁₂A = 2,8, 2
ii) ₆B = 2,4
iii) ₁₄C = 2, 8, 4
iv) ₁₃D = 2, 8, 3
a) Which of these belong to the same group?
b) Which of these belong to the same period?
Answer:
a) ₆B and ₁₆C belong to the same group.
b) ₁₂A, ₁₄C and ₁₃D belong to the same period.

III. Answer any four questions from 11-15. Each carries 3 scores. (4 × 3 = 12)

Question 11.
Match the items in columns A & B suitably.

A	B
Plum pudding model	James Chadwick
Planetary model of atom	Goldstein
Canal rays	J.J. Thomson
Neutron	Rutherford

Answer:

A	B
Plum pudding model	J.J. Thomson
Planetary model of atom	Rutherford
Canal rays	Goldstein
Neutron	James Chadwick

Question 12.
The atomic numbers of two elements are given below.
Mg = 12 O = 8
a) Write the electron configuration of these elements.
b) Which type of compound will be formed if these two elements combine together?
c) Draw the electron dot diagram of the compound formation.
Answer:

Question 13.
The symbols of three atoms are given below.
₆C¹², N¹⁴, ₆C¹⁴
a) Which of these are isotopes?
b) What is the basis of your selection?
c) Write any use of an isotope.
Answer:
a) \({ }_6^{12} \mathrm{C}\) and \({ }_6^{14} \mathrm{C}\) are isotopes.
b) Atoms having the same atomic number and different mass numbers.
c) \({ }_6^{14} \mathrm{C}\) isotope is used to determine the age of fossils and prehistoric objects.

Question 14.
Compare the properties of ionic and covalent compounds.
Answer:

Properties	Ionic	Covalent
State	Solid	Solid, Liquid and gaseous
Solubility	Soluble in water	Insoluble in water soluble in Organic solvents
Electrical conductivity	Conducts electricity in aqueous and molten states	Generally, do not conduct electricity
Melting point	High	Usually low
Boiling point	High	Low

Question 15.
a) What is the method used to indicate the size of an atom?
b) Which are the factors that affect the size of atom?
c) What happens to the size of atom as we moving from left to right along a period?
Answer:
a) Atomic radius
b) Nuclear charge and number of shells
c) As we move along the period, the size of the atom decreases.

IV. Answer any four questions from 16-20. Each carries 4 scores. (4 × 4 = 16)

Question 16.
a) Mark the oxidation number of atoms in the chemical equations given below.
i) Zn + 2HCI → ZnCl2 + H2
ii) NaOH + HCI → NaCl + H2O
b) Which of these is a redox reaction?
Answer:

Question 17.
The electronegativity values of two elements are given below. (C = 2.55, H= 2.20)
a) Which type of compound will be formed, if these two elements combine together? Give reason.
b) Draw the electron dot diagram of the chemical bonding in the CH, molecule. (Atomic no. C = 4, H = 1)
Answer:
a) Covalent compound
The difference in the electronegativity values is less than 1.7.
(There is not much difference in the electronegativity values).
b)

Question 18.
An unbalanced chemical equation is given
N₂ + H₂ → NH₃
a) Which are the reactants in this reaction?
b) Balance the above chemical equation.
c) What is the total number of product molecules in the balanced chemical equation?
d) Identify the compound in this equation.
Answer:
a) Nitrogen, Hydrogen
b) N₂ + 3H₂ → 2NH₃
c) 2 molecules (2 Ammonia molecules)
d) Ammonia (NH₃)

Question 19.
Oxygen molecule (O₂) and Nitrogen molecule (N₂) are formed by covalent bonding.
a) Which type of covalent bond is formed in N₂ molecule.?
b) How many pairs of electrons are shared in the O₂ molecule?
c) Draw the electron dot diagram illustrating the formation of chemical bonds in the O₂ molecule [Hint: Atomic number of O = 8, N = 7]
Answer:
a) Triple bond
b) 2 pair

Question 20.
Certain statements related to the modern periodic table are given below. Find out which of these statements are related to.
a) Included in the 18th group
b) Show the properties of metals as well as non-metals.
c) Included in the 3- 12 groups.
d) Included in period 6 and also known as rare earths.
Answer:
a) Noble gases
b) Metalloids
c) Transition elements
d) Lanthanoides