Chemistry Confusion


Clicking the image above will take you to an 11-question quiz that purports to test your general knowledge of chemistry.  Unfortunately, the quiz is so rife with misunderstandings that you’ll only be testing your ability to decipher the intentions of the quiz-maker.  Let’s examine the quiz question by question to see where it goes wrong (and, to be fair, what it got right).

Question the First:  An atom is the smallest unit of matter. The central part of an atom is called?

  • nucleon
  • nucleus
  • neutron

You’re meant to choose nucleus, and I agree that this is the best answer  (although in the case of hydrogen-1, the nucleus is a nucleon; a proton, to be precise).  So what’s the problem?  I don’t approve of how the question is worded.   Atoms are not the smallest unit of matter, they are the smallest units of elements that still have the properties of elements.  For example, potassium atom is the smallest unit of potassium that still behaves like potassium, but there are smaller things than atoms.  A potassium atom – nay, almost any atom –  can be further divided, albeit with some difficulty, into even smaller pieces called protons, neutrons, and electrons.  Electrons appear to be elementary particles; i.e. they are not made of smaller particles.  But protons and neutrons are made of tinier particles called quarks.  So no…atoms are not the smallest units of matter.

Now you might say: “This is just a dumb Internet chemistry quiz!  What difference does it make if the author distinguishes between ‘the smallest unit of matter’ and ‘the smallest unit of an element that still has the properties of an element?'”  I’ll tell you what difference it makes, inquisitive reader: chemistry is a science of distinctions.  Chemists – and other scientists – spend their careers trying to define phenomena with ever-increasing precision.  To anybody who really understands and appreciates chemistry, these over-generalized statements simply will not do.  If my pedantry on this question offends you, you may wish to go read something else; it’s only going to get worse as the questions continue.

Question the Second: Protons and neutrons are in the center of the atom, making up the nucleus. What is it surrounding by? [sic]

  • electrons
  • nucleons
  • nuclei

While I agree with the best answer choice (electrons), I take umbrage at the poor grammar.  I know, I know: you don’t need perfect grammar to understand the finer points of chemistry; however, if you intend to write a quiz in English for an English-speaking audience, you ought to nail down the basics of English grammar, don’t you think?

Question the Third: Sodium chloride is an ionic compound with the chemical formula, NaCl. It is also known as?

  • baking powder
  • bleach
  • table salt

The correct answer is table salt.  There’s nothing particularly wrong with this question – in fact, I’m pleasantly surprised that the quiz-maker did not refer to NaCl as a molecule – so let’s move on.

Question the Fourth: All of the following are states of matter EXCEPT:

  • liquid
  • gas
  • plasma
  • solid

The quiz means for you to choose plasma, but that’s just wrong.  Plasma is a state of matter.  A plasma is a gas that has been energized to the point that its atoms have been thrashed into positive ions and electrons.  The plasma state of matter is not very common on Earth (except in high-energy events like lightning strikes) but plasmas are super common in the rest of the Universe.  Every single star is made of plasma, which means that plasma is the most common state of matter in the visible Universe by a very wide margin.

Question the Fifth: K is the chemical symbol for what element commonly found in bananas?

  • calcium
  • potassium
  • krypton

The correct answer is potassium.  There’s nothing terribly wrong with this question.  As an interesting side note, I’d like to mention that bananas contain potassium ions, not elemental potassium.  What’s the difference?  Elemental potassium atoms have 19 electrons; potassium ions, K+, have only 18 electrons.  That might not seem like a huge deal, but believe me: you would not want to eat bananas containing elemental potassium.  The video below shows what happens when elemental potassium reacts with water.

So yeah…be grateful for that lost electron.

Question the Sixth: The boiling point of water is?

  • 212º Fahrenheit
  • 100º Fahrenheit
  • 373.15º Fahrenheit

Really?  Fahrenheit questions on a modern chemistry quiz?  All right, the correct answer is 212º Fahrenheit.  100º is the boiling point of water on the Celsius scale, and 373.15 is the boiling point of water in Kelvins.

If you’ve studied chemistry, you know about the Celsius and Kelvin scales.  Either one of those would have been a more appropriate choice for this question.  I’m just saying.

Question the Seventh: Fill in the blanks: Water is a compound made by joining _____ hydrogen and ______ oxyen [sic]

  • 1 hydrogen and 2 oxygen
  • 2 hydrogen and 1 oxygen
  • 3 hydrogen and 1 oxygen

The correct answer is 2 hydrogen and 1 oxygen.  Spelling error aside, this question is fine.  Onward.

Question the Eighth: The pH scale measures how acidic or basic a substance is. The pH scale ranges from 0 to 14. A pH of 4 is considered to be:

  • acidic
  • neutral
  • basic

The correct answer is acidic.  My nit-pick is minor: 0 and 14 are not the absolute limits of the pH scale.  A strongly acidic solution can have a negative pH – that is, a pH less than zero – and a strongly basic solution can have a pH greater than 14.  Granted: you aren’t likely to encounter a solution whose pH is outside of the 0 to 14 range in your daily life (unless you have a career working with some really nasty chemicals).  This question could have been improved by adding the words “For most household solutions” at the start of the second sentence.

Question the Ninth: Which of the following elements is the most malleable metal of all?

  • silver
  • gold
  • iron
  • platinum

The correct answer is gold.  A material is malleable if it can be hammered or rolled into very thin sheets without breaking.  In this, gold excels.  A single gram of gold can be beaten into a sheet with an area of one square meter.  Gold leaf can be hammered thin enough to become transparent.  So I give the quiz credit for this one.  Moving on.

Question the Tenth: The first period on the periodic table is what element?

  • oxygen
  • helium
  • argon
  • hydrogen

Oh chemistry quiz: you were doing so well for the last three questions.

On the periodic table, a period is a row of elements.  The modern periodic table has seven periods, the first of which contains two elements: hydrogen and helium.  The quiz gives credit for choosing hydrogen but not for helium, which makes me think that the author meant to write “The first element on the periodic table…”  But that’s not what he wrote, so the question has two correct answers, one of which is not awarded.  For shame.

Question the Last: Laughing gas or happy gas is the world’s oldest general anesthetic. What is the chemical name of this popular dental sedative?

  • nitrous oxide
  • nitrogen peroxide
  • nitric oxide

The correct answer is nitrous oxide, but is that really the world’s oldest general anesthetic?  Not by a long shot.  This is more of a historical quibble, but it’s a quibble nonetheless.  Opium and alcohol were being used as general anesthetics long before nitrous oxide was discovered by Joseph Priestly in the 18th century.  (Its anesthetic properties were discovered by the poster child of self-experimentation, Humphry Davy.)  I’m not sure why the quiz’s author believed otherwise.

I don’t feel that this quiz does a good job of judging a person’s general chemistry knowledge, but then again, maybe it does.  Maybe you have to know so much about chemistry that you can see past the author’s obvious errors to determine what he or she was probably trying to say.  If so, that’s an interesting and sure-to-be-controversial way of assessing knowledge.  I can imagine the uproar when assessments everywhere adopt this strategy: Instead of unambiguous questions that have only one correct answer, you’ll be given grammatically-questionable puzzlers whose answer choices may or may not include a defensible answer.  If you really know the material, you’ll be able to figure out what they’re trying to say, despite the author’s best efforts to obfuscate the meaning.  If not…well, there’s always summer school.

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