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9th-grade-vocabulary-words

English Vocabulary · Grade 9 Live Review Preview

9th Grade Vocabulary Words

Ninth grade marks the transition to high-school reading and writing across literature, argument, research, biology, physical and Earth science, algebra, computing, world history, civics, and geography. This level develops precise academic and domain-specific vocabulary while strengthening context, nuance, source evaluation, figurative language, and evidence-based communication.

This independently authored 800-word beta curriculum is arranged in twenty-three pages of up to thirty-five words. Pages containing words 1–500 include five cloze questions drawn only from that enhanced range; words 501–800 remain fully visible and editable as list pages while the expanded practice layer is developed. Each row includes a subject-field label and an editable word-study note about a transparent affix, compound structure, capitalization, or dictionary base form. The cited Grade 9 resources calibrate difficulty and study skills only; all learner-facing definitions, examples, quizzes, and descriptions are original KSSR copy.

Please note: the vocabulary lists for grades 9~11 have been selected to ensure no overlap with the previous grade level. If the words are too specialized or difficult for you, please go back to grade levels 4~8 and review the words on those pages.

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800 words
Words 316–350 of 800
#WordDetailsMeaningSample sentence
316solution concentrationnoun
Study

Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: solution + concentration. Study the complete expression as one field-specific unit.

the amount of dissolved substance in a given amount of solutionEvaporation increased the solution concentration.
317molaritynoun
Study

Field: Grade 9 physical, Earth, and environmental-science term

Word study: Suffix focus: -ity commonly forms a noun naming a quality, state, or condition.

solution concentration measured in moles of solute per liter of solutionThe beaker contained a molarity of 0.5 moles per liter.
318pH scalenoun
Study

Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: pH + scale. Study the complete expression as one field-specific unit.

a numerical scale describing how acidic or basic an aqueous solution isPure water is near 7 on the pH scale.
319acid-base indicatornoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: acid + base + indicator. Study the complete expression as one field-specific unit.

a substance whose color changes over a range of acidity or basicityLitmus is an acid-base indicator that turns red in acid.
320electrolytenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Base-form focus: electrolyte is the dictionary headword; compare its inflected or derived forms in context.

a substance that forms ions in solution and allows the solution to conduct electricityDissolved salt is an electrolyte.
321nonelectrolytenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Prefix focus: non- means not or without.

a substance that dissolves without forming enough ions to conduct electricitySugar is a nonelectrolyte in water.
322oxidation numbernoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: oxidation + number. Study the complete expression as one field-specific unit.

a bookkeeping value representing an atom's apparent charge in a compoundOxygen usually has an oxidation number of negative two.
323redox reactionnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: redox + reaction. Study the complete expression as one field-specific unit.

a reaction involving electron transfer and changes in oxidation numbersRusting is a redox reaction in which iron loses electrons.
324electron transfernoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: electron + transfer. Study the complete expression as one field-specific unit.

movement of one or more electrons from one atom or species to anotherElectron transfer occurs from zinc to copper ions in the cell.
325synthesis reactionnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: synthesis + reaction. Study the complete expression as one field-specific unit.

a chemical reaction in which simpler substances combine to form a more complex productA synthesis reaction joins hydrogen and oxygen to form water.
326decomposition reactionnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: decomposition + reaction. Study the complete expression as one field-specific unit.

a chemical reaction in which one compound breaks into simpler substancesHeating calcium carbonate causes a decomposition reaction.
327single-replacement reactionnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: single + replacement + reaction. Study the complete expression as one field-specific unit.

a reaction in which one element replaces another element in a compoundZinc replacing hydrogen in acid is a single-replacement reaction.
328double-replacement reactionnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: double + replacement + reaction. Study the complete expression as one field-specific unit.

a reaction in which ions from two compounds exchange partnersThe two clear solutions undergo a double-replacement reaction and form a solid.
329precipitation reactionnoun
Study

Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: precipitation + reaction. Study the complete expression as one field-specific unit.

a solution reaction that produces an insoluble solidMixing silver nitrate and sodium chloride causes a precipitation reaction.
330net ionic equationnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: net + ionic + equation. Study the complete expression as one field-specific unit.

an equation showing only the particles that directly change during a solution reactionThe net ionic equation omits ions that remain unchanged.
331scalarnoun
Study

Field: Grade 9 physical, Earth, and environmental-science term

Word study: Base-form focus: scalar is the dictionary headword; compare its inflected or derived forms in context.

a quantity described by size alone without directionTemperature is a scalar.
332vectornoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Base-form focus: vector is the dictionary headword; compare its inflected or derived forms in context.

a quantity described by both size and directionVelocity is a vector because its direction matters.
333vector magnitudenoun
Study

Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: vector + magnitude. Study the complete expression as one field-specific unit.

the size or numerical length of a vectorThe arrow's length represents the vector magnitude.
334instantaneous velocitynoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: instantaneous + velocity. Study the complete expression as one field-specific unit.

an object's speed and direction at one particular momentThe speedometer approximates the car's instantaneous velocity.
335average accelerationnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: average + acceleration. Study the complete expression as one field-specific unit.

change in velocity divided by the time over which the change occursThe runner's average acceleration was greatest during the first two seconds.
336linear momentumnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: linear + momentum. Study the complete expression as one field-specific unit.

the product of an object's mass and velocityA moving truck has more linear momentum than a bicycle at the same speed.
337impulsenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Base-form focus: impulse is the dictionary headword; compare its inflected or derived forms in context.

force multiplied by the time it acts, equal to the resulting change in momentumAn air bag extends the stopping time and changes the passenger's momentum with a smaller impulse force.
338rotational inertianoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: rotational + inertia. Study the complete expression as one field-specific unit.

an object's resistance to a change in its rotational motionMoving mass farther from an axis increases rotational inertia.
339force equilibriumnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: force + equilibrium. Study the complete expression as one field-specific unit.

a state in which forces balance and the net force is zeroA hanging lamp at rest is in force equilibrium.
340frictional forcenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: frictional + force. Study the complete expression as one field-specific unit.

a force resisting motion or attempted motion between touching surfacesThe frictional force between shoes and the floor prevents slipping.
341gravitational forcenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: gravitational + force. Study the complete expression as one field-specific unit.

the attractive force between objects with massEarth's gravitational force pulls the ball downward.
342normal forcenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: normal + force. Study the complete expression as one field-specific unit.

a support force exerted perpendicular to a contacting surfaceThe table's normal force balances the book's weight.
343applied forcenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: applied + force. Study the complete expression as one field-specific unit.

a push or pull exerted on an object by a person or another objectThe worker's applied force moved the crate across the floor.
344tension forcenoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: tension + force. Study the complete expression as one field-specific unit.

a pulling force transmitted through a taut rope, string, or cableThe cable's tension force supports the elevator.
345free-body diagramnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: free + body + diagram. Study the complete expression as one field-specific unit.

a sketch showing all external forces acting on one chosen objectThe free-body diagram includes gravity, support, and friction.
346Newton's first lawproper noun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: Newton's + first + law. Study the complete expression as one field-specific unit.

the law that motion remains unchanged unless a net external force actsNewton's first law explains why a puck keeps sliding on nearly frictionless ice.
347Newton's second lawproper noun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: Newton's + second + law. Study the complete expression as one field-specific unit.

the law relating net force to mass and accelerationNewton's second law predicts greater acceleration when the same mass receives a larger force.
348Newton's third lawproper noun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: Newton's + third + law. Study the complete expression as one field-specific unit.

the law that interacting objects exert equal and opposite forces on each otherNewton's third law pairs the swimmer's push on water with water's push on the swimmer.
349conservation of momentumnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: conservation + of + momentum. Study the complete expression as one field-specific unit.

the principle that total momentum remains constant in an isolated systemConservation of momentum explains the motion of two skaters who push apart.
350elastic collisionnoun
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Field: Grade 9 physical, Earth, and environmental-science term

Word study: Term structure: elastic + collision. Study the complete expression as one field-specific unit.

a collision in which both total momentum and total kinetic energy are conservedAn ideal elastic collision allows two hard spheres to rebound without losing kinetic energy.

Vocabulary reading and practice

Forces and Solutions

Reading practice for pages 10–12. Five relevant words are highlighted.

English reading

A beaker rests on a scale while gravitational force pulls it downward and normal force from the scale pushes upward. Inside, a precipitation reaction forms a solid from two clear solutions. The chemist describes each solution concentration with molarity, the number of moles of dissolved substance per liter of solution.

Reading comprehension

1. Which force pulls the beaker downward?

Gravitational force pulls it downward.

2. What forms during a precipitation reaction?

A solid forms from the solutions.

3. What does molarity measure?

Molarity measures moles of solute per liter of solution.

Vocabulary quiz

Complete 5 review questions for this page.

1. Earth's ___ pulls the ball downward.

Answer: gravitational force

2. Evaporation increased the ___.

Answer: solution concentration

3. Mixing silver nitrate and sodium chloride causes a ___.

Answer: precipitation reaction

4. The table's ___ balances the book's weight.

Answer: normal force

5. The beaker contained a ___ of 0.5 moles per liter.

Answer: molarity

Sources and curriculum references

These references guide selection and calibration. Definitions, sample sentences, readings, questions, and teaching notes are independently written and reviewed.