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Grade 12 Chemistry model exam, 2016 E.C. (2024)

A model exam set in 2016 E.C. to prepare Grade 12 students for the Chemistry entrance exam, in the same format. It is practice, and it is not the entrance exam paper itself. Every question comes with the correct answer and a worked explanation.

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  • Natural science stream

    Who sits it

  • 2016 E.C. model exam

    Exam year

  • Arada sub-city

    Set by

  • 78 questions with answers

    In this set

Try questions from this paper

Answer each question yourself before opening the answer. The explanations point to the exact place in the textbook, so you know which page to reread when you miss one.

Question 1

Which model of an atom describes an atom as a positive sphere where electrons are embedded in a sphere?

  1. A.Ernest Rutherford
  2. B.J.J. Thomson
  3. C.Neil's Bohr
  4. D.John Dalton
Show the answer and explanation

Answer: B J.J. Thomson

Why

J.J. Thomson proposed the plum pudding model of the atom, which describes the atom as a sphere of positive charge with negatively charged electrons embedded within it, like raisins in a pudding.

Question 2

An element X has two stable naturally occurring isotopes (816X^{16}_{8}X & 818X^{18}_{8}X). If the average atomic mass of element X is 16.2 a. m. u. what is the percentage abundance of 816X^{16}_{8}X ?

  1. A.90
  2. B.25
  3. C.10
  4. D.75
Show the answer and explanation

Answer: A 90

Why

Using the average atomic mass formula: 16.2=16x+18(1−x)16.2 = 16x + 18(1 - x), we solve for xx (the fractional abundance of 816X^{16}_8X) to get x=0.90x = 0.90, which corresponds to a 90%90\% abundance.

Question 4

Which of the following property decreases across a period of the periodic table?

  1. A.Ionization energy
  2. B.Atomic size
  3. C.Effective nuclear charge
  4. D.Electron affinity
Show the answer and explanation

Answer: B Atomic size

Why

Atomic size decreases across a period because the effective nuclear charge increases, which pulls the outer electrons closer to the nucleus.

Question 5

Unequal distribution of the shared electrons between two atoms results in the formation of -

  1. A.Polar covalent bond
  2. B.Non-polar covalent bond
  3. C.Electrovalent bond
  4. D.Co-ordinate covalent bond
Show the answer and explanation

Answer: A Polar covalent bond

Why

A polar covalent bond is formed when there is an unequal sharing of electrons between two atoms with different electronegativities, leading to partial charges.

Question 6

Which of the following is non-polar molecule?

  1. A.NH₃
  2. B.HF
  3. C.CCl₄
  4. D.SO₂
Show the answer and explanation

Answer: C CCl₄

Why

CCl4CCl_4 has a highly symmetrical tetrahedral geometry where the individual polar C−ClC-Cl bond dipoles cancel each other out, making the overall molecule non-polar.

Question 7

According to Boyle’s law, doubling the pressure of a sample of gas, what will be the volume of gas at constant temperature?

  1. A.Doubled
  2. B.Tripled
  3. C.Halved
  4. D.One third
Show the answer and explanation

Answer: C Halved

Why

According to Boyle's law, pressure and volume are inversely proportional at constant temperature (P1V1=P2V2P_1V_1 = P_2V_2), so doubling the pressure halves the volume.

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The other Chemistry papers of 2016 E.C.

2016 E.C. (2024)2016 E.C. (2024), Tigray

Chemistry papers from other years

2018 E.C. (2026)2018 E.C. (2026), version 12018 E.C. (2026), version 22018 E.C. (2026), version 42017 E.C. (2025)2017 E.C. (2025), round 12017 E.C. (2025), version 22015 E.C. (2023)2014 E.C. (2022)2013 E.C. (2021)2012 E.C. (2020)2011 E.C. (2019)2010 E.C. (2018)2009 E.C. (2017)2008 E.C. (2016)2007 E.C. (2015)2006 E.C. (2014)2005 E.C. (2013)

More papers like this one

All Grade 12 Chemistry papersAll papers of 2016 E.C.Every subject and year

Revise Chemistry before you sit this paper

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Is this the real Grade 12 entrance exam?

No. It is a model exam set in 2016 E.C. (2024) to prepare students for the entrance exam, in the same format. Our set holds 78 of its questions, each with its answer and a worked explanation.

Where are the real entrance exam papers?

The Grade 12 entrance exam papers we hold are on the exam papers page, listed by year beside the model exams.

Can I download this model exam as a PDF?

Yes, and it is free. The question paper is one file and the answer key with its worked explanations is another, so you can try it first. Print them, or keep them on your phone for revision when there is no data.

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