Common Core LiteracyGrades 11–12Science & Technical

RST.11-12.4: Symbols and Terms in Their Science Sense

Also written as CCSS.ELA-LITERACY.RST.11-12.4 · Cluster: Craft and Structure.

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The Official Wording

Determine the meaning of symbols, key terms, and other domain-specific words and phrases as they are used in a specific scientific or technical context relevant to grades 11-12 texts and topics.

Common Core State Standards, Grades 11-12, Reading: Science & Technical Subjects · Read it at the source · Checked October 14, 2026

What RST.11-12.4 Means in Plain English

Juniors and seniors work out what symbols, equations and specialist terms mean in the particular science text in front of them. In a chemistry passage on Gibbs free energy, “spontaneous” means thermodynamically favored, not sudden, and each symbol in ΔG = ΔH − TΔS has a precise job.

Ninth and tenth grade (RST.9-10.4) did the same work with grades 9-10 texts and topics. Grades 11-12 bring denser notation and more words whose science meaning departs from everyday use. This is the last band of the line, the technical vocabulary college and career readiness assumes.

RST.11-12.4 I Can Statements

I can explain what each symbol in a science equation stands for.
I can tell a term’s science meaning from its everyday meaning.
I can use a term’s precise meaning to explain an example.

RST.11-12.4 Worked Example

The passage is written for this page. The weak answer reads spontaneous as everyday English, and the strong one reads it, and every symbol, the way a chemist would.

Read the Story

Whether a reaction can proceed on its own at constant temperature and pressure is decided by the change in Gibbs free energy, ΔG = ΔH − TΔS. Here ΔH is the change in enthalpy, the heat the reaction releases or absorbs; ΔS is the change in entropy, roughly how spread out the energy and matter become; and T is the temperature in kelvins.A negative ΔG means the reaction is spontaneous. In chemistry the word says nothing about speed; it means only that the reaction is thermodynamically favored and can continue without a steady supply of outside energy.Diamond turning into graphite has a negative ΔG at room temperature, so the change is spontaneous, yet no diamond ring has ever become pencil lead. Its carbon atoms would first have to break some of the strongest bonds known, so the rate is effectively zero: the change is thermodynamically favored but kinetically hindered.Temperature enters through the TΔS term. Melting ice absorbs heat, so ΔH is positive, but liquid water is more disordered, so ΔS is positive too; above 273 K, TΔS outweighs ΔH, ΔG turns negative, and ice melts on its own.

A short passage written for this page.

Question: What does “spontaneous” mean in this passage, and how do the symbols in ΔG = ΔH − TΔS explain why ice melts on its own above 273 K but not below it?

Not Yet“Spontaneous means the reaction happens suddenly, without warning. Diamond turning into graphite is spontaneous, so diamonds slowly crumble. Ice melts above 273 K because it gets warm enough.”It uses the everyday meaning of spontaneous, which the passage rules out, and draws a false conclusion about diamonds from it. It never reads the symbols, so it cannot explain why 273 K is the turning point.

Meets the Standard“Here spontaneous means thermodynamically favored, a negative ΔG, and says nothing about speed; diamond becomes graphite spontaneously but at a rate of effectively zero. For ice, ΔH is positive because melting absorbs heat, which pushes ΔG up, while ΔS is positive because liquid water is more disordered, so the TΔS term pulls ΔG down. That term is multiplied by the temperature in kelvins, so it grows as T rises. Above 273 K it outweighs ΔH, ΔG is negative, and ice melts on its own; below 273 K, ΔH wins and ΔG stays positive.”It defines spontaneous by the passage’s technical meaning, reads each symbol and its sign in context, and uses the equation itself to explain the turning point.

Question Stems to Use

What does this word mean in everyday speech, and what does it mean in this text?What does each symbol in the equation stand for, and in what units?What does a positive or negative sign tell you here?Which example does the author use to rule out the everyday meaning?How would you explain the term to someone who knows only its everyday sense?

Common Mistakes with RST.11-12.4

Reading a technical term in its everyday sense

“Spontaneous means it happens all of a sudden.”

Try this: Have students write the everyday meaning and the text’s meaning side by side, then cite the sentence that separates them.

Skipping the symbols

A summary of the passage that never mentions ΔH, ΔS or T

Try this: Ask students to read the equation aloud in words, naming each symbol, its sign in the example and its units.

Forgetting that T is in kelvins

“At 25 degrees, TΔS is just 25 times ΔS.”

Try this: Point to where the text defines each symbol’s units, and have students convert every temperature to kelvins before reasoning with the equation.

Where RST.11-12.4 Fits

Comes BeforeRST.9-10.4Determine the meaning of symbols and key terms in grades 9-10 science and technical texts.

AlongsideL.11-12.6Acquire and use general academic and domain-specific words and phrases accurately.WHST.11-12.2Use precise language and domain-specific vocabulary to manage a complex technical topic.

Comes NextRST.11-12.5Analyze how a text sorts its ideas into categories or hierarchies, built from the terms that name them.

Practice RST.11-12.4

Vocabulary Worksheet GeneratorFree ToolBuild a worksheet from a unit’s technical terms and symbols, then add a column for each word’s everyday meaning to contrast with its science sense.Chemistry termsGrades 11-12Everyday vs science

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Quick Check

What does “spontaneous” mean in this passage?
Thermodynamically favored, with a negative ΔG. It says nothing about how fast the reaction happens.
Why doesn’t a diamond turn into graphite, if the change is spontaneous?
Its atoms would first have to break very strong bonds, so the rate is effectively zero: favored but kinetically hindered.
Why does ice melt on its own above 273 K but not below it?
Above 273 K the TΔS term outweighs the positive ΔH, so ΔG is negative; below it, ΔH wins and ΔG is positive.

RST.11-12.4: Other Names

RST.11-12.4CCSS.ELA-LITERACY.RST.11-12.4