Kerala Syllabus Class 10 Chemistry Model Question Paper Set 1

Practicing Chemistry Question Paper Class 10 Kerala Syllabus Set 1 English Medium helps identify strengths and weaknesses in a subject.

Chemistry Class 10 Kerala Syllabus Model Question Paper Set 1

Time: 1 ½ Hours
Total Score: 40

Instructions:

1. First fifteen minutes are cool off time. Read the questions carefully during this time:
2. Write the answers according to the instructions.
3. Consider the score while writing the answers.
4. Answer only one question for questions having choice.

I. Answer all the questions from 1 to 4. Each question carries 1 score. (4 × 1 = 4)

Question 1.
The metal which is refined by distillation is _____.
(Sn, Cu, Hg, Pb)
Answer:
Hg

Question 2.
Match the following

Choose the correct answer from the options given below.

(a) (b) (c)
A. (ii) (i) (iii)
B. (i) (ii) (iii)
C. (iii) (i) (ii)
D. (ii) (iii) (i)
Answer:
D. (ii) (iii) (i)

Question 3.
Which one of the following organic compounds undergoes an addition reaction?
A. CH₃ – CH₃
B. CH₄
C. CH₃C1
D. CH₂ = CH₂
Answer:
D. CH₂ = CH₂

Question 4.
Statement 1: Substitution reactions are chemical reactions in which an atom or group of atoms is replaced with another atom or group of atoms in a compound.

Statement 2: Polymerisation is the process by which simple molecules join together to form large complex molecules.
Which of the following options is true, regarding these statements?

A. Statements 1 and 2 are correct.
B. Statement 1 is correct, but 2 is not correct.
C. Statement 1 is not correct, but 2 is correct.
D. Statements 1 and 2 are not correct.
Answer:
A. Statements 1 and 2 are correct

II. Two questions from 5 to 11 have choice. Each question carries 2 scores. (7 × 2 = 14)

Question 5.
The structural formulae of four organic compounds are given.
(i) CH₃ – CH₂ -CH₂-CH₃
(ii) CH₃ – CH₂ – O – CH₃
(iii) CH₃ – CH₂ – CO – CH₃
(iv) CH₃ – CH₂ – CH₂ – OH
(a) Write the structural formula of the chain isomer of compound (i)
(b) Identify the pair of functional isomers.
Answer:
(a)

(b) (ii) and (iv)

Question 6.
Calcination and Roasting are two methods of conversion of concentrated ore into its oxide.
(a) How does Roasting differ from Calcination?
(b) Cu₂S ore is converted into Cu₂O by. ______ process.
Answer:
a) Roasting is the process of heating the metal ore at a temperature below its melting point in the presence of air
b) Roasting

Question 7.
(A) The IUPAC name of a hydrocarbon is 2, 3-Dimethylbutane.
(a) Write the structural formula of the given hydrocarbon.
(b) A hydrocarbon has 4 carbon atoms in the main chain. There are two methyl groups on the second carbon atom. Write its IUPAC name.
Answer:

(b) (b) 2,2-Dimethylbutane

OR
(B) Write the structural formula of given compounds
(i) 2,3-Dimethylbutane
(ii) But-2-ene
Answer:
(i) 2, 3-Dimethylbutane

(ii) CH₃ – CH = CH – CH₃

Question 8.
How do the following conditions affect a reversible reaction?
i) More reactants are added.
ii) Products are removed.
Answer:
i) The rate of forward reaction increases
ii) Rate of forward reaction increases

Question 9.
Copper is electroplated on an iron ring.
(a) Which electrolyte is used here?
(b) Which metal is connected to the positive terminal of the battery?
Answer:
a) Copper sulphate solution
b) Cu

Question 10.
(A) Ethanol is an alcohol that is extensively used for industrial purposes.
(a) What is rectified spirit?
(b) How does rectified spirit differ from absolute alcohol?
Answer:
a) Rectified spirit is 95.6% pure ethanol. It is obtained by the fractional distillation of wash.
b) Absolute alcohol is 99.5% pure ethanol. It is obtained by the fractional distillation of rectified spirit.

OR
(B) Consider the following chemical equation.

(a) Write the structural formula of A.
(b) What is the product obtained when A is subjected to polymerisation?
Answer:
a) CH₂ = CH₂
b) Polyethene

Question 11.
Choose the suitable method used in each of the following processes from the bracket.
[Liquation, Leaching, Troth floatation, Distillation]
(a) Concentration of sulphide ores.
(b) Refining of metals with low boiling points.
Answer:
a) Froth floatation
b) Distillation

III. Two questions from 12 to 17 have choice. Each question carries 3 scores. (6 × 3 = 18)

Question 12.
Chemical equations of the reactions taking place in the blast furnace during the industrial production of iron are given below.
(i) C + O₂ → CO₂ + Heat
(ii) CO₂ + C + Heat → 2CO
(iii) Fe₂O₃ + 3CO → 2Fe + 3CO₂
(iv) CaCO₃ → CaO + CO₂
(v) CaO + SiO₂ → CaSiO₃
Answer the following questions.
a) Which compound acts as the reducing agent?
b) What is the function of CaO in the production of iron?
c) Which is the slag formed here?
Answer:
a) Carbon monoxide (CO)
b) Act as a flux to remove Silica (SiO₂)
c) Calcium silicate (CaSiO₃ )

Question 13.
(A) The molecular mass of methane (CH₄) is 16.
(a) What is the mass of 1 GMM of CH₄?
(b) Calculate the number of moles in 160 g of CH₄
(c) What is the mass of 5 × 6.022 × 10²³ CH₄ molecules?
Answer:
a) 16g

b) Number of moles
= \(\frac{\text { Mass given in grams }}{\text { Gram molecular mass of the compound }}\)
= \(\frac{160 \mathrm{~g}}{16 \mathrm{~g}}\) = 10 moles

c) Number of moles x molecular mass
= 5 × 16 = 80 g

OR
(B) The CO₂ gas kept at STP has a volume of 112 L. [Hint: Molecular mass – 44]
(a) Find the number of moles of CO₂
(b) Calculate the mass of 112 L CO₂
(c) How many molecules of CO₂ are present in it?
Answer:
a) No. of molecules = Volume at STP/22.4
\(\frac{112}{22.4}\) = 5 moles

b) Mass = No. of moles x Molar mass
= 5 moles × 44 = 220g

c) No.of molecues = No.of moles × 6.022 × l0²³
= 5 × 6.022 × 10²³

Question 14.
A gas kept in cylinder A, having a volume of 5 L at 4 atm pressure, is completely transferred to cylinder B of volume 10 L at constant temperature.
(a) What is the volume of the gas in cylinder B?
(b) What will be the pressure in cylinder B?
(c) Which Gas law is associated with this situation?
Answer:
a) 10L
b) P₁V₁ = P₂V₂
P₁ = 4 atm
V₁ = 5L,
V₂ = 10 L
P₂ = ?
P₂ = P₁V₂/V₂
\(\frac{4 \times 5}{10}\) = 2 atm

c) Boyle’s law

Question 15.
Match columns A, B and C suitably.

A Characteristics of ore	B Method of concentration	C Example
Ore particles are heavier than the impurities	Froth floation	Tin stone
Ore particles are lighter than the impurities	Magnetic separation	Ore of gold
Magnetic nature of ore	Levigation	Zinc sulphide

Answer:

A Characteristics of ore	B Method of concentration	C Example
Ore particles are heavier than the impurities	Levigation	Ore of gold
Ore particles are lighter than the impurities	Froth floation	Zinc sulphide
Magnetic nature of ore	Magnetic separation	Tin stone

Question 16.
(A)
(a) The size of air bubbles rising from the bottom of a water tank increases. Give a reason.
(b) State the gas law related to it.
(c) The volume of a fixed mass of a gas at 2 atm pressure is 20 L. What will be its volume if the pressure increases four times without changing the temperature?
Answer:
a) Boyle’s Law
b) At a constant temperature, volume of a definite mass of gas is inversely proportional to its pressure.
c) 5L

OR
(B)
(a) If the volume of a gas at 127°C and 1 atm pressure is 1600 L, what will be the volume of the gas at 600 K and 2 atm pressure?
Answer:
\(\frac{P_1 V_1}{T_1}=\frac{P_2 V_2}{T_2}\)
P₁ = 1 atm
V₁ = 1600L
T₁= 127°C = 127 + 273 = 400 K
P₂ = 2 atm
T₂ = 600 K
V₂ = ?
\(\frac{1 \times 1600}{400}=\frac{2 \times V_2}{600}\)
V₂ = \(\frac{960000}{800}\) = 1200 L

(b) The volume of a certain mass of gas at 1 atm is 1600 L. What will be the volume if the pressure is increased to 4 atm (temperature remains unchanged)?
Answer:
P₁ V₁ = P₂ V₂
P₁ = 1 atm
V₁ =1600L
P₂ = 4 atm
V₂ = ?
1 x l600 = 4 x V₂
V₂ = \(\frac{1600}{4}\) = 400L

Question 17.

How do the following changes influence the amount of the product?
(a) Temperature decreases.
(b) Pressure increases.
(c) Ammonia produced is removed continuously from the system
Answer:
a) Amount of product increases
b) Amount of product increases
c) Amount of product increases

Question 18 has choice. It carries 4 scores. (1 × 4 = 4)

Question 18.
(A) The subshell electron configuration of chromium (₂₄Cr) is written in two ways.
(i) ls² 2s² 2p⁶ 3s² 3p⁶ 3d⁴ 4s²
(ii) ls² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹
(a) Which is the most stable configuration?
(b) Explain the reason for your answer
(c) Write the stable subshell electron configuration of coppeT (₂₉Cu)
(d) Write the period number and group number of copper.
Answer:
a) (ii) ls² 2s² 2p⁶ 3s² 3p⁶ 3d⁵ 4s¹
b) Half-filled d subshell has greater stability.
c) ls² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s¹
d) Period number = 4, Group number = 11

OR
(B) The subshell electron configuration of certain elements are given below:
A – ls² 2s² 2p⁶ 3s²
B – ls² 2s² 2p⁴
C – ls² 2s² 2p⁶ 3s² 3p⁶
D – Is² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ 4s²

i) Write the atomic number of the element ‘A’.
ii) Which is the inert gas among them?
iii) The element ‘D’ can form coloured compounds. Explain the reason.
iv) Write the chemical formulae of the compound formed by the elements ‘A’ and ‘B’
Answer:
i) 12
ii) C
iii) D – Transition elements
iv) ABb