SAT Form, Structure, and Sense Question

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Question 1 · Medium · Reading and WritingDecember 2024 · Q17Form, Structure, and Sense · 0 solved

In a chemical reaction, the value known as molar mass helps convert between the mass of the reactants and the mass of the product. The gaseous <u>________</u> have molar masses of 42.08 and 44.10 g/mol, respectively. Which choice completes the text so that it conforms to the conventions of Standard English?

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Strategy

Decide whether the naming phrase is restrictive (essential) or nonrestrictive (extra). Use no commas for a restrictive appositive; use a comma before and after a nonrestrictive appositive. Avoid inserting a period inside a noun phrase, which would break the sentence before the verb.

Hints (open one at a time)

Hint 1

Focus on how “propylene and propane” relates to the word “compounds.” Is it renaming them?

Hint 2

Recall the appositive rule: essential appositives take no commas; nonessential ones are set off with commas on both sides.

Hint 3

Read each option into the sentence and check for two things: no stray period before the verb and, if commas are used, that there’s a matching pair.

Step-by-step Explanation

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The trap here

The comma pair that changes what a sentence means — Whether the commas go in depends on whether the phrase is essential. The SAT tests the meaning, not the sound.