Grade 12 results are out. Where to check yours

Exam papers

Grade 12 Chemistry entrance exam, 2009 E.C. (2017)

Real questions from the Grade 12 university entrance exam in Chemistry, as students sat it in 2009 E.C. Every question comes with the correct answer and a worked explanation.

Start practicing freeQuestion paper

  • Natural science stream

    Who sits it

  • 2009 E.C. (2017)

    Exam year

  • 69 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 of the following covalent bonds is the most polar?

  1. A.H - F
  2. B.H - C
  3. C.H - H
  4. D.H - N
Show the answer and explanation

Answer: A H - F

Why

The polarity of a covalent bond is determined by the difference in electronegativity between the bonded atoms. The electronegativity difference is greatest between hydrogen (2.2) and fluorine (4.0), making the H-F bond the most polar.

Question 2

The force that hold different atoms or ions together are called?

  1. A.Electric forces
  2. B.Physical bonds
  3. C.Chemical bond
  4. D.Atomic forces
Show the answer and explanation

Answer: C Chemical bond

Why

A chemical bond is the attractive force that holds atoms or ions together to create molecules or compounds.

Question 3

How many electrons are shared between two atoms in a double bond?

  1. A.2
  2. B.3
  3. C.4
  4. D.6
Show the answer and explanation

Answer: C 4

Why

A covalent bond shares pairs of electrons; a single bond consists of 2 shared electrons, while a double bond consists of 2 pairs, which equals 4 shared electrons.

Question 5

What is the chemical formula of the compound formed by aluminium (III) and sulphate ion, SO42−\mathrm{SO_4^{2-}} ?

  1. A.AlSO4\mathrm{AlSO_4}
  2. B.Al2SO4\mathrm{Al_2SO_4}
  3. C.Al2(SO4)3\mathrm{Al_2(SO_4)_3}
  4. D.Al(SO4)3\mathrm{Al(SO_4)_3}
Show the answer and explanation

Answer: C Al2(SO4)3\mathrm{Al_2(SO_4)_3}

Why

Aluminium forms a 3+ cation (Al³⁺) and sulfate is a 2- polyatomic anion (SO₄²⁻). To balance the charges to zero, two Al³⁺ ions combine with three SO₄²⁻ ions to give Al₂(SO₄)₃.

Question 6

Which of the following is the most reasonable valence- bond structure of the nirocyl chloride (NOCl)? [Figure: The four options are scanned Lewis (electron-dot) structures, one per option, each drawn on a pale lilac background. Option A: ':O - N - Cl' written with capital letters; the O has a pair of dots above it, a pair of dots to its left (drawn as a colon) and a pair of dots below it, and is joined to N by a single horizontal line; the N has a pair of dots above and a pair of dots below, and is joined to Cl by a short single dash; the Cl has a pair of dots above and a pair of dots below. Option B: 'O = N - Cl'; the O has a pair of dots above and a pair of dots below and is joined to N by a double line (two parallel horizontal strokes); the N has one pair of dots above it only; N is joined to Cl by a short single dash; the Cl has a pair of dots above and a pair of dots below. Option C: ': O - N = Cl'; a pair of dots stands to the left of O, and O also has a pair of dots above and a pair of dots below; O is joined to N by a single short dash; N has a pair of dots above and a pair of dots below; N is joined to Cl by a double line; Cl has a pair of dots above and a pair of dots below. Option D: ': O = N Cl'; a pair of dots stands to the left of O and a pair of dots above it; O is joined to N by a double line; N has a pair of dots above and a pair of dots below; Cl stands with no bond line drawn to N and carries a pair of dots above and a pair of dots below. The tick marking the key sits at the end of option B's line.]

  1. A.O and N joined by a single bond, N and Cl joined by a single bond; O carries three lone pairs (above, left and below), N carries two lone pairs (above and below), Cl carries two lone pairs (above and below)
  2. B.O and N joined by a double bond, N and Cl joined by a single bond; O carries two lone pairs (above and below), N carries one lone pair (above), Cl carries two lone pairs (above and below)
  3. C.O and N joined by a single bond, N and Cl joined by a double bond; O carries three lone pairs (left, above and below), N carries two lone pairs (above and below), Cl carries two lone pairs (above and below)
  4. D.O and N joined by a double bond, no bond drawn between N and Cl; O carries two lone pairs (left and above), N carries two lone pairs (above and below), Cl carries two lone pairs (above and below)
Show the answer and explanation

Answer: B O and N joined by a double bond, N and Cl joined by a single bond; O carries two lone pairs (above and below), N carries one lone pair (above), Cl carries two lone pairs (above and below)

Why

In nitrosyl chloride (NOCl), nitrogen is the central atom bonded to oxygen via a double bond and to chlorine via a single bond (O=N-Cl), giving each atom a complete octet and minimizing formal charges.

Question 8

Which of the following is the correct order for electrons filling in orbitals?

  1. A.3s, 3p, 4s, 3d
  2. B.2p, 3s, 3p, 3d
  3. C.3p, 4s, 3d, 5s
  4. D.4s, 3d, 4p, 4d
Show the answer and explanation

Answer: A 3s, 3p, 4s, 3d

Why

According to the Aufbau principle (the (n + l) rule), the filling order of orbitals is 3s (n+l = 3), 3p (n+l = 4), 4s (n+l = 4, lower n), and then 3d (n+l = 5).

Download the whole paper as a PDF

All 69 questions in this set as a printed paper, and the answer key with 65 worked explanations as a second file. Print them or read them with no data.

Free, and it needs no account.

Question paperAnswer key and explanations

Sit the full paper, timed and scored

A free Temari account gives you the whole Chemistry paper, and every other year, as timed mock exams with instant scoring. It works on any phone, even over a weak connection.

Start practicing free

Chemistry papers from other years

2018 E.C. (2026)2017 E.C. (2025)2016 E.C. (2024)2015 E.C. (2023)2014 E.C. (2022)2013 E.C. (2021)2012 E.C. (2020)2011 E.C. (2019)2010 E.C. (2018)2008 E.C. (2016)2007 E.C. (2015)2006 E.C. (2014)2005 E.C. (2013)

Revise Chemistry before you sit this paper

The Grade 12 Chemistry short notes hold 22 cards. Each one gives the rule, what its symbols stand for and the mistake that costs marks, chapter by chapter from the national textbook.

Open the Chemistry notes
Are these the real 2009 E.C. Chemistry entrance exam questions?

Yes. They come from the national university entrance exam in Chemistry that students sat in 2009 E.C. (2017). Our set holds 69 of its questions, each with its answer and an explanation that points back to the textbook.

How do I practice the full paper?

Create a free account with a phone number. The full paper runs as a timed mock exam with instant scoring, and the AI tutor upgrade at 199 ETB per month can walk you through anything you miss.

Can I download the Chemistry 2009 E.C. paper 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 attempt the paper first. Print them, or keep them on your phone for revision when there is no data.

Sign inCreate your account