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    Class 11 UT-1 SET A (2023-24)

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    Class 11 UT-1 SET A (2023-24)

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    4 views2 pages

    Class 11 UT-1 SET A (2023-24)

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    vinitkumar22471

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    © All Rights Reserved
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    SET-A

    ARMY PUBLIC SCHOOL, DHAULA KUAN


    Examination: UT I (2023-24)
    CLASS: XI SUBJECT: Chemistry (043)
    TIME: 1hr M.M:30
    General Instructions:
    All questions are compulsory.
    Marks are indicated against each question.

    Q1. Neutrons are present in all atoms except: 1


    (a) He (b) H (c) C (d) Ne

    Q2. Which of the following contains more number of molecules? 1


    (a) 1 g of CO2 (b) 1g of N2 (c) 1 g of H2 (d) 1 g of CH4

    Q3. In 250 mL of a 0.5M NaCl solution, water is added to make the solution 500mL. 1
    The concentration of the resultant solution is:
    (a) 0.1 M (b) 0.125 M (c) 0.167 M (d) 0.25 M

    Q4. How many moles of He gas occupy 56 L at 0ºC and 1 atm pressure: 1
    (a) 2.5 (b) 2.0 (c) 3.0 (d) 1.5

    Q5. Given below are two statements labelled as Assertion (A) and Reason (R) 1
    Assertion (A): Atomic mass of Na is 23.
    Reason(R): An atom of sodium is 23 times heavier than 1/12th mass of one atom
    of C–12 isotope.

    Select the most appropriate answer from the options given below:
    (a) Both A and R are true and R is the correct explanation of A
    (b) Both A and R are true but R is not the correct explanation of A.
    (c) A is true but R is false.
    (d) A is false but R is true

    Q6 (a) Write two differences between molarity and molality. 2


    (b) Calculate the mass percent of Sodium and Sulphur in sodium sulphate.

    Q7. Write the features of Rutherford model of an atom. 2

    Q8. A compound contains 4.07% hydrogen, 24.27% carbon and 71.65% chlorine. Its 3
    molecular mass is 98.96. What are its empirical and molecular formulae?

    Q9. (a) Define law of multiple proportion. 3


    (b) The following data are obtained when dinitrogen and dioxygen react together to
    form different compounds:
    Mass of dinitrogen Mass of dioxygen
    14 g 16 g
    14 g 32 g
    28 g 32 g
    28 g 80 g
    Show that the given data are in agreement with the law of multiple proportion.
    Q10. The density of 3M solution of NaCl is 1.25 g/mL . Calculate molality of the 3
    solution.
    Q11. (a) Arrange the following electromagnetic radiations in increasing order of 3
    frequency: IR, Cosmic rays, radio waves, UV rays.
    (b) Calculate the wavenumber and frequency of yellow radiation having wavelength
    5800Å.
    Q12. Mole, also spelled mol, in chemistry, a standard scientific unit for 4
    Case measuring large quantities of very small entities such as atoms, molecules, or
    Study other specified particles. The mole designates an extremely large number of units,
    Question 6.02214076 × 1023.
    The General Conference on Weights and Measures defined the mole as this
    number for the International System of Units (SI) effective from May 20, 2019. The
    mole was previously defined as the number of atoms determined
    experimentally to be found in 12 grams of carbon–12. The number of units in a
    mole also bears the name Avogadro’s number, or Avogadro’s constant, in honor of
    the Italian physicist Amedeo Avogadro (1776–1856). Avogadro proposed that equal
    volumes of gases under the same conditions contain the same number of molecules,
    a hypothesis that proved useful in determining atomic and molecular weights and
    which led to the concept of the mole.

    Answer the following questions:


    (a) What is the ratio of molecules between 1 mole of H2O and 1 mole of
    C12H22O11 ?
    (b) Calculate the mass of 1 atom of 14C.
    (c) Why do atomic masses of most of the elements in atomic mass units
    involve fraction?
    (d) What is the mass of a mole of heavy water (D2O)?

    Q13. Calcium carbonate reacts with aqueous HCl to give CaCl2 and CO2 according to the 5
    reaction,
    CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l)
    (a) Calculate the amount of CO2 gas produced when 20 g of CaCO3 reacts with 25 g
    of HCl.
    (b) Will any of the two reactants remain unreacted?
    (c) If yes, which one and what would be its mass?

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