Approaching the SAT Subject Test in Chemistry

As you’re preparing your college applications, you’ll find that many schools require a number of SAT II subject tests in addition to the normal SAT test. Since you’ll almost certainly be taking more of these tests than subjects you’ll be majoring in (or perhaps even truly interested in), you’ll often find that at least one of these tests is particularly challenging. Today, we’ll look at what sort of questions you can expect on the SAT Subject test in Chemistry and go over some tips on how to approach the exam. Chemistry Test Format: The SAT II chemistry consists of 85 multiple choice questions; there are no short answer or open-ended questions to worry about. Furthermore, all of the questions on the test fall into one of three broad categories: Five-choice completion questions, classification questions, or relationship-analysis question. Let’s take a look at examples of each question type. Five-choice completion question: These are your standard multiple choice questions. EX1) Which of the following might be the active ingredient in household bleach? (A) NaCl (B) Na2O (C) NaOCl (D) NaOH (E) HCl This is a typical sort of â€Å"you either know it or you don’t† type question. There’s no math, no chemical equation to construct, just a question about the properties of specific chemical substances. The answer here is C—sodium hypochlorite is a bleaching agent commonly used in household products. EX2) If 50.0 g of CaCO3 reacts completely with excess hydrochloric acid at STP, how many liters of carbon dioxide gas will be produced? (A) 11.2 (B) 22.4 (C) 25.0 (D) 44.8 (E) 50.0 This is representative of the sorts of calculations that may appear on the test. Note that you are not allowed to use a calculator, however, most of the questions will use numbers that make the math easy. In this example, we need to know the chemical equation: CaCO3 + 2 HCl à   CaCl2 + H2O + CO2. The molecular mass of CaCO3 is 100.0 g/mol (easy!), so 50.0 g is 0.500 mol. According to our equation, this should produce 0.500 mol of CO2. Finally, recall that at STP, one mole of gas occupies 22.4 L, so 0.500 mol occupies half that, or 11.2 L. The correct answer is therefore A. Classification questions: These are slightly different in that you’re given a set of answer choices that will be used for a series of questions. (A) Na 2O (B) O2 (C) CO2 (D) SO2 (E) SO3 EX3) Yields the most acidic solution when dissolved in water. EX4) Exhibits the least amount of covalent character in its bonding. Again, for these types of questions, you’re choosing from the same set of 5 answer choices for a series of 2-3 questions. In most cases these are â€Å"rapid-fire† knowledge based questions, as demonstrated here. For these questions, our answers are: EX3: E. Only choices C, D, and E yield acidic solutions in water. Of the three acids produced (H2CO3 ¸H2SO3, and H2SO4) only the last is a strong acid. EX4: A. The electronegativities of sodium (an electropositive, first column metal) and oxygen (a rather electronegative non-metal) are most different, indicating a high degree of ionic, rather than covalent, bonding. Relationship analysis questions: The final type of question is unique to the chemistry exam. On your answer sheet these always start with #101, and show up as two T/F choices plus another box labeled â€Å"CE†. The way these work is you’ll be given two statements. For each statement, determine whether it is true or false, then, if both are true, determine if the second statement is a correct explanation of the first. These tend to be the trickiest, but not necessarily the hardest, on the exam. EX5) I. Acetic acid is readily soluble in water BECAUSE II. Acetic acid is an organic acid In this example, both statements are true—acetic acid is indeed soluble in water, and is it also an example of an organic acid. But is it soluble in water because it is an organic acid? Try to think of a counterexample if you can—you may recall that fatty acids (such as the oleic acid in olive oil) are also organic acids, but these do not dissolve well in water. So the answer here is T, T. EX6) I. Zinc metal will reduce Cu2+ ions in aqueous solution BECAUSE II. Zinc is a more active metal than copper This example may be a little harder in terms of content, since many introductory chemistry courses don’t really get into electrochemistry. It turns out here that both statements are indeed true, and II correctly explains I, so the correct answer would be T, T, CE. Odds and Ends: As the example questions may have hinted at, when you sit down to take the SAT II Chemistry exam, you may be faced with material that you’ve never seen, or â€Å"knowledge† based questions that you just don’t know the answer to. The good news is that you don’t need to get every question right to earn an 800 on the test. This is especially a relief since the test will also test your time-management skills—you’ll have only 60 minutes to complete all 85 questions. Scoring is relatively straightforward—you earn one point for each correct response and lose one for each incorrect response. Questions left blank don’t earn or lose any points. Typically, a raw score above 80-81 will be an 800. Thus, you can leave 3-4 questions blank, or incorrectly guess on 1-2 without it affecting your score all that much. The chemistry SAT II isn’t really a test you can cram for, since a lot of the material is pretty straightforward knowledge-based stuff that you’ll be exposed to over a year of chemistry. In particular, the exam will also test your familiarity with laboratory equipment and procedures, so you’ll definitely want at least a high-school course + lab behind you before taking the test. A year of algebra (including logarithms) is also strongly recommended to help with some of the more advanced calculation type problems. The test does have a reputation as being among the harder SAT II tests, but with a little practice and attention to detail, you’ll have no problems with it! ;