Cracking the SAT Chemistry Subject Test

take this percent composition and figure out the substance’s empirical formula. Here’s how you do it. Imagine, ...

DRILL 1 Question Type A Questions 1–4 refer to the following. (A) N 2 O (B) C 6 H 12 O 6 (C) SO 3 (D) NO (E) N 2 O 5 ...

102. ...

Question Type C The formula for calcium nitrate is Ca(NO 3 ) 2 . What is its approximate formula weight? (A) 64 am ...

CHEMICAL REACTIONS—HOW MOLECULES ARE FORMED, BROKEN DOWN, AND REFORMED In the course of a chemical reaction, t ...

are 5 × 2 = 10 oxygen atoms. Now do the same for the right side of the equation. In 4H 2 O, there are 4 ...

(C) 4 (D) 5 (E) 6 Fortunately, these questions are easy to answer if you use the “plug-in” b ...

STOICHIOMETRY Sometimes SAT Chemistry questions will ask you to determine how much product is form ...

Consider this question: If 34 g of ammonia and 32 g of oxygen are combined, how many grams of nitrogen ...

THERMODYNAMICS Entropy One of the most important things to remember about thermodynamics is that low-energy sta ...

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The universe, it turns out, likes disorder. Systems move toward increasing disorder. They also tend ...

reaction. Exothermic reaction → energy is released → ΔH < 0 → enthalpy decreases Endothermic reaction ...

they’ll ask you to figure out ∆Hf for the whole reaction. That’s simple to do; you just add up the heats of format ...

Spontaneity and Gibbs Free Energy A spontaneous reaction is one that will occur at a given temperatur ...

DRILL 2 Question Type A Questions 5–7 refer to the following. (A) Gibbs free energy (B) Heat of formation ( ...

104. ...

Question Type C ...C 2 H 4 (g) +...O 2 (g) →...CO 2 (g) +...H 2 O(l) If the equation for the reaction above ...

2Al(s) + Fe 2 O 3 (s) → Al 2 O 3 (s) + 2Fe(s) If 80 grams of Al and 80 grams of Fe 2 O 3 are c ...

Summary A molecule is a unit consisting of two or more atoms. The elements that exist as diatomic m ...