Difference between revisions of "HS-PS1-11"

From NY Science Standards Wiki
(Section order: Vocabulary now comes before Performance Level Descriptions)
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== Phenomena ==
 
== Phenomena ==
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The NYSED-specific disciplinary core idea for HS-PS1-11 (see [[#NGSS Dimensions|NGSS Dimensions]] below) names the contexts in which acids and bases matter: ''"agricultural applications, environmental impacts (acid rain), animal and plant physiology"'' and the daily lives of humans and other organisms. The question clusters NYSED has released for this performance expectation draw on the same contexts: a blueberry field, the New York fruit industry, pool water, and beverages.
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<gallery mode="packed" heights="150">
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File:Finger Lakes vineyard (Plutor).jpg|Vines above Seneca Lake in the Finger Lakes. Grapes grow best at a soil pH of 5.5–6.5. Photo: Plutor, CC BY 2.0
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=== Environmental impacts: acid rain in the Adirondacks ===
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File:Blueberry field (Hannes Grobe).jpg|A commercial blueberry field. Blueberries need acidic soil, pH 4.5–5.0. Photo: Hannes Grobe, CC BY-SA 4.0
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[[File:Big Moose Lake NY USA.jpg|thumb|right|320px|alt=Big Moose Lake in the Adirondacks, a calm forest-lined lake seen from a dock|Big Moose Lake in the western Adirondacks, one of the most closely studied acidified lakes in North America. Photo: James H. Dunning, CC BY-SA 2.5, via Wikimedia Commons.]]
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File:Red raspberries on bush (Tomwsulcer).jpg|Raspberries take up less magnesium as soil pH drops. Photo: Tomwsulcer, CC0
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Rain is naturally slightly acidic (pH ≈ 5.6) because dissolved carbon dioxide forms carbonic acid. Through the 20th century, sulfur dioxide and nitrogen oxides from coal-burning power plants in the Midwest were carried east on prevailing winds and returned to the ground as sulfuric and nitric acid, making precipitation in the Adirondacks far more acidic than normal. The region's thin soils and granite bedrock contain few carbonate minerals, so its lakes have little capacity to neutralize acid. When the Adirondack Lakes Survey Corporation sampled 1,469 lakes and ponds between 1984 and 1987, roughly a quarter had a pH of 5.0 or below and nearly half had little or no buffering capacity; many had lost their brook trout. Acidic water also leaches aluminum from soil, and dissolved aluminum damages fish gills. The 1990 Clean Air Act Amendments cut sulfur dioxide emissions sharply, and sulfate in Adirondack lakes has been falling since, but pH and acid-neutralizing capacity are recovering slowly and full recovery is expected to take decades.
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File:Outdoor swimming pool (Ildar Sagdejev).jpg|Pool water is kept near pH 7.4 so that hypochlorous acid can sanitize it. Photo: Ildar Sagdejev, CC BY-SA 4.0
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File:Aluminum soda can (Tony Webster).jpg|Acidic drinks need a plastic liner to keep them from corroding the aluminum. Photo: Tony Webster, CC BY 2.0
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File:Iodine clock reaction (Daniel J. Lulu).jpg|The end point of an iodine clock reaction. Photo: Daniel J. Lulu, CC BY-SA 4.0
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=== Agricultural applications: growing blueberries and apples ===
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File:Big Moose Lake NY USA.jpg|Big Moose Lake in the Adirondacks, one of the most studied acid-rain lakes in North America. Photo: James H. Dunning, CC BY-SA 2.5
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Most crops grow best in soil that is near neutral, and farmers routinely "lime" fields with crushed limestone to raise the pH of acidic soil, a neutralization reaction carried out on the scale of an entire field. Blueberries are the exception: they need acidic soil, around pH 5.0, and at higher pH they cannot take up iron and their leaves turn yellow. To lower soil pH, growers work elemental sulfur into the soil, where soil bacteria slowly oxidize it to sulfuric acid, or fertilize with ammonium sulfate, which is both a nitrogen source and an acidifier. Because both adjustments take months and are easy to overshoot, soil pH testing is a normal part of managing an orchard or berry field in New York. This is the context behind the ''A Profitable Blueberry Field'' sample cluster and the ''Fruit Industry in New York State'' cluster from August 2026.
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File:Blue hydrangea (Dwight Sipler).jpg|Bigleaf hydrangea blooms blue in acidic soil and pink in alkaline soil. Photo: Dwight Sipler, CC BY 2.0
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</gallery>
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The NYSED-specific disciplinary core idea for HS-PS1-11 (see [[#NGSS Dimensions|NGSS Dimensions]] below) names the contexts in which acids and bases matter: ''"agricultural applications, environmental impacts (acid rain), animal and plant physiology"'' and the daily lives of humans and other organisms. Every phenomenon that a released Regents question has used to assess this standard is listed below, with a link to the question that uses it.
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=== Animal and plant physiology ===
 
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[[File:Blue hydrangea (Dwight Sipler).jpg|thumb|right|320px|alt=Close-up of blue and purple bigleaf hydrangea flowers|Bigleaf hydrangea blooms in shades of blue in acidic soil and pink in neutral or alkaline soil: a living pH indicator. Photo: Dwight Sipler, CC BY 2.0, via Wikimedia Commons.]]
 
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Living things depend on keeping acids and bases in a narrow balance. Human stomach acid is mostly hydrochloric acid at a pH of about 1.5 to 3.5, which activates digestive enzymes and kills most microbes; antacid tablets are weak bases such as calcium carbonate or magnesium hydroxide that neutralize excess acid. Blood, by contrast, is held between pH 7.35 and 7.45 by the bicarbonate buffer system, and a shift of even a few tenths of a pH unit is a medical emergency. Plants respond to the acidity of their surroundings too. Bigleaf hydrangeas are the classic example: in acidic soil, aluminum ions become soluble, the plant absorbs them, and the flowers turn blue; in neutral or alkaline soil the aluminum stays locked up and the same plant blooms pink. Gardeners change the color deliberately by adding aluminum sulfate or garden lime.
 
  
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=== Agricultural applications: soil pH ===
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* '''Grape and apple orchards.''' New York is the third-largest grape producer and second-largest apple producer in the United States, and soil pH is one of the factors that limits yield. Grapes grow best in soil with a pH of 5.5–6.5, while apples do best in well-drained soil at pH 6.0–7.0, and students compare the hydronium ion concentrations of the two optimal ranges. — [[Questions:The Fruit Industry in New York State#q1|The Fruit Industry in New York State]] (August 2026, Question 6)
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* '''Testing a blueberry field.''' Blueberries need unusually acidic soil, with optimal growth between pH 4.5 and 5.0. A farmer's soil test comes back with a hydronium ion concentration of 1.0 × 10<sup>−8</sup> M (pH 8), far too basic, and students choose which two acid-base indicators together could confirm whether the soil has reached the target range. — [[Questions:PSC A Profitable Blueberry Field#q1|A Profitable Blueberry Field]] (Sample cluster, Question 1)
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* '''Acidifying soil with elemental sulfur.''' Growers lower soil pH by working elemental sulfur into the field, where soil bacteria oxidize it to sulfuric acid: 2S + 3O<sub>2</sub> + 6H<sub>2</sub>O → 4H<sub>3</sub>O<sup>+</sup> + 2SO<sub>4</sub><sup>2−</sup>. Students connect a drop of 3 pH units to a thousandfold increase in hydronium ion concentration. — [[Questions:PSC A Profitable Blueberry Field#q2|A Profitable Blueberry Field]] (Sample cluster, Question 2)
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* '''Ammonium fertilizer as a gentler acidifier.''' Because sulfur can over-acidify soil, farmers may use ammonium sulfate instead: the ammonium ion donates a hydrogen ion to water (NH<sub>4</sub><sup>+</sup> + H<sub>2</sub>O ⇌ NH<sub>3</sub> + H<sub>3</sub>O<sup>+</sup>) and is also oxidized by soil bacteria to nitrate and H<sup>+</sup>. Students identify the ammonium ion as the acid and water as the base and explain the pattern of behavior behind each label. — [[Questions:PSC A Profitable Blueberry Field#q3|A Profitable Blueberry Field]] (Sample cluster, Question 3)
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* '''Raspberries and magnesium uptake in the Finger Lakes.''' Plants absorb aqueous magnesium ions from the soil for photosynthesis, but absorption is cut in half when soil pH falls from 6.5 to 4.5. Raspberries grow best at pH 5.5–6.5, so soil in the northern Finger Lakes (pH above 7) is acidified with elemental sulfur, aluminum sulfate or manure, while limestone and dolomite raise the pH of soils that are too acidic. Students compare the hydronium ion concentration at pH 6.5 with that at pH 4.5. — [[Questions:Photosynthetic Pathways#q3|Photosynthetic Pathways]] (June 2026, Question 40)
  
 
=== Daily life: pools and beverages ===
 
=== Daily life: pools and beverages ===
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Two of the released question clusters for HS-PS1-11 use ordinary consumer settings. In a swimming pool, chlorine dissolves to form hypochlorous acid, which partly ionizes to the hypochlorite ion. The un-ionized hypochlorous acid is the far better disinfectant, and the balance between the two forms depends on pH, so pool operators keep the water in the CDC-recommended range of pH 7.0 to 7.8, lowering it with muriatic (hydrochloric) acid or sodium bisulfate and raising it with sodium carbonate. In beverages, carbonic and phosphoric acid give colas a pH of about 2.5 to 3.5, coffee sits near 5, and milk near 6.7. Tooth enamel begins to dissolve below a pH of about 5.5, which is why dentists worry more about sipping soda all afternoon than about a single glass at dinner.
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* '''Cloudy pool water.''' After a pool has been covered all winter, high phosphate levels feed algae, and calcium and magnesium ions combine with carbonate ions to form precipitates that cloud the water; a rise in pH above the optimal range makes precipitates form as well. Hypochlorous acid, HClO(aq), sanitizes the pool, and dilute hydrochloric acid is added to stabilize its concentration. Students decide which ion's concentration should be increased to reduce cloudiness. — [[Questions:Pool Water Chemistry#q2|Pool Water Chemistry]] (August 2026, Question 23)
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* '''Testing pool water with indicators.''' A water-quality test on a pool sample reports a pH of 5.5 along with calcium hardness, free chlorine and phosphate levels. Given the color-change ranges of methyl orange, bromothymol blue, phenol red and bromocresol green, students predict the color each indicator turns in the sample. — [[Questions:Pool Water Chemistry#q4|Pool Water Chemistry]] (August 2026, Question 25)
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* '''Acidic drinks in aluminum cans.''' Some canned beverages need a plastic lining to keep the acidic drink from corroding the aluminum. Given the pH of six beverages, from cola (2.3–2.9) and white grape juice (3.4) up to fortified water (9.0–9.5), students count how many would require the lining. — [[Questions:Chemistry of Beverages#q4|Chemistry of Beverages]] (June 2026, Question 9)
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* '''Telling two sport drinks apart.''' One sport drink has a pH of 3.0–3.5 and another a pH of 8.8. Using the color-change ranges of bromocresol green, indigo carmine, phenol red and thymol blue, students pick the pair of indicators that would distinguish the two drinks. — [[Questions:Chemistry of Beverages#q5|Chemistry of Beverages]] (June 2026, Question 10)
  
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=== Laboratory investigations ===
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* '''The iodine clock reaction.''' In a clock reaction the end point announces itself with a sudden color change: here, molecular iodine formed from potassium iodate and sodium bisulfite turns a starch solution dark blue. In the first step, IO<sub>3</sub><sup>−</sup> + 3HSO<sub>3</sub><sup>−</sup> → I<sup>−</sup> + 3H<sup>+</sup> + 3SO<sub>4</sub><sup>2−</sup>, the bisulfite ion gives up hydrogen ions, and students identify it as the acid because it is a hydrogen ion donor. — [[Questions:Clock Reaction#q3|Clock Reaction]] (June 2026, Question 30)
  
 
== {{Resourcesheading}} ==
 
== {{Resourcesheading}} ==

Revision as of 01:18, 16 October 2026

← HS-PS1-7
HS-PS1-12 →

Plan and conduct an investigation to compare properties and behaviors of acids and bases.

Clarification statement: Examples of properties could include pH values (concentration), neutralization capability and conductivity. Observations of behaviors could include the effects on indicators, reactions with other substances, and efficacy in performing titrations.

Assessment boundary: Reactions are limited to Arrhenius and Bronsted-Lowry acid-base reactions.

Note: this is a NYSED-specific performance expectation that is different from the Next Generation Science Standards.

Regents Exam Questions

Released New York State Regents exam questions that assess HS-PS1-11 are listed here by exam and question cluster. Each link opens the question with its answer key.

Exam Cluster Question
August 2026 Chemistry Regents The Fruit Industry in New York State Question 6
Pool Water Chemistry Question 23
Pool Water Chemistry Question 25
June 2026 Chemistry Regents Chemistry of Beverages Question 9
Chemistry of Beverages Question 10
Clock Reaction Question 30
Photosynthetic Pathways Question 40
Chemistry sample clusters (Spring 2025) A Profitable Blueberry Field Question 1
A Profitable Blueberry Field Question 2
A Profitable Blueberry Field Question 3

Vocabulary

Terms from the Chemistry Glossary that come from this standard or from the released exam questions that assess it.

From this standard
  • accuracy
  • acid
  • acid rain
  • acid-base reaction
  • Arrhenius acid-base reaction
  • base
  • Bronsted-Lowry acid-base reaction
  • chemical reaction
  • claim
  • concentration
  • conductivity
  • evidence
  • indicator
  • investigation
  • neutralization
  • neutralization capability
  • pH
  • phenomenon
  • precision
  • properties
  • reaction
  • substance
  • system
  • titration
From released exam questions
Implied by this standard
  • acidic, basic and neutral solutions – implied by "pH values"
  • pH scale – implied by "pH values (concentration)"

Performance Level Descriptions

Every Regents exam question on HS-PS1-11 is written to match one of the performance level descriptions (PLDs) below.

Level 1: Given an investigation plan or provided information, select appropriate tools and/or materials that could be used to identify a property or behavior of an acid or base.
Level 2: Given the results of an investigation or provided information, calculate a quantity or make a claim to identify a property and/or behavior of an acid or base.
Level 3: Given a plan, conduct an investigation or given the results of an investigation or provided information, compare the properties and/or behaviors of acids and/or bases.
Level 4: Plan and conduct an investigation to compare properties and behaviors of acids and bases.
Level 5: Plan and conduct multiple investigations to compare, explain, and predict properties and behaviors of acids and bases.

Phenomena

  • Vines above Seneca Lake in the Finger Lakes. Grapes grow best at a soil pH of 5.5–6.5. Photo: Plutor, CC BY 2.0

  • A commercial blueberry field. Blueberries need acidic soil, pH 4.5–5.0. Photo: Hannes Grobe, CC BY-SA 4.0

  • Raspberries take up less magnesium as soil pH drops. Photo: Tomwsulcer, CC0

  • Pool water is kept near pH 7.4 so that hypochlorous acid can sanitize it. Photo: Ildar Sagdejev, CC BY-SA 4.0

  • Acidic drinks need a plastic liner to keep them from corroding the aluminum. Photo: Tony Webster, CC BY 2.0

  • The end point of an iodine clock reaction. Photo: Daniel J. Lulu, CC BY-SA 4.0

  • Big Moose Lake in the Adirondacks, one of the most studied acid-rain lakes in North America. Photo: James H. Dunning, CC BY-SA 2.5

  • Bigleaf hydrangea blooms blue in acidic soil and pink in alkaline soil. Photo: Dwight Sipler, CC BY 2.0

The NYSED-specific disciplinary core idea for HS-PS1-11 (see NGSS Dimensions below) names the contexts in which acids and bases matter: "agricultural applications, environmental impacts (acid rain), animal and plant physiology" and the daily lives of humans and other organisms. Every phenomenon that a released Regents question has used to assess this standard is listed below, with a link to the question that uses it.

Agricultural applications: soil pH

  • Grape and apple orchards. New York is the third-largest grape producer and second-largest apple producer in the United States, and soil pH is one of the factors that limits yield. Grapes grow best in soil with a pH of 5.5–6.5, while apples do best in well-drained soil at pH 6.0–7.0, and students compare the hydronium ion concentrations of the two optimal ranges. — The Fruit Industry in New York State (August 2026, Question 6)
  • Testing a blueberry field. Blueberries need unusually acidic soil, with optimal growth between pH 4.5 and 5.0. A farmer's soil test comes back with a hydronium ion concentration of 1.0 × 10−8 M (pH 8), far too basic, and students choose which two acid-base indicators together could confirm whether the soil has reached the target range. — A Profitable Blueberry Field (Sample cluster, Question 1)
  • Acidifying soil with elemental sulfur. Growers lower soil pH by working elemental sulfur into the field, where soil bacteria oxidize it to sulfuric acid: 2S + 3O2 + 6H2O → 4H3O+ + 2SO42−. Students connect a drop of 3 pH units to a thousandfold increase in hydronium ion concentration. — A Profitable Blueberry Field (Sample cluster, Question 2)
  • Ammonium fertilizer as a gentler acidifier. Because sulfur can over-acidify soil, farmers may use ammonium sulfate instead: the ammonium ion donates a hydrogen ion to water (NH4+ + H2O ⇌ NH3 + H3O+) and is also oxidized by soil bacteria to nitrate and H+. Students identify the ammonium ion as the acid and water as the base and explain the pattern of behavior behind each label. — A Profitable Blueberry Field (Sample cluster, Question 3)
  • Raspberries and magnesium uptake in the Finger Lakes. Plants absorb aqueous magnesium ions from the soil for photosynthesis, but absorption is cut in half when soil pH falls from 6.5 to 4.5. Raspberries grow best at pH 5.5–6.5, so soil in the northern Finger Lakes (pH above 7) is acidified with elemental sulfur, aluminum sulfate or manure, while limestone and dolomite raise the pH of soils that are too acidic. Students compare the hydronium ion concentration at pH 6.5 with that at pH 4.5. — Photosynthetic Pathways (June 2026, Question 40)

Daily life: pools and beverages

  • Cloudy pool water. After a pool has been covered all winter, high phosphate levels feed algae, and calcium and magnesium ions combine with carbonate ions to form precipitates that cloud the water; a rise in pH above the optimal range makes precipitates form as well. Hypochlorous acid, HClO(aq), sanitizes the pool, and dilute hydrochloric acid is added to stabilize its concentration. Students decide which ion's concentration should be increased to reduce cloudiness. — Pool Water Chemistry (August 2026, Question 23)
  • Testing pool water with indicators. A water-quality test on a pool sample reports a pH of 5.5 along with calcium hardness, free chlorine and phosphate levels. Given the color-change ranges of methyl orange, bromothymol blue, phenol red and bromocresol green, students predict the color each indicator turns in the sample. — Pool Water Chemistry (August 2026, Question 25)
  • Acidic drinks in aluminum cans. Some canned beverages need a plastic lining to keep the acidic drink from corroding the aluminum. Given the pH of six beverages, from cola (2.3–2.9) and white grape juice (3.4) up to fortified water (9.0–9.5), students count how many would require the lining. — Chemistry of Beverages (June 2026, Question 9)
  • Telling two sport drinks apart. One sport drink has a pH of 3.0–3.5 and another a pH of 8.8. Using the color-change ranges of bromocresol green, indigo carmine, phenol red and thymol blue, students pick the pair of indicators that would distinguish the two drinks. — Chemistry of Beverages (June 2026, Question 10)

Laboratory investigations

  • The iodine clock reaction. In a clock reaction the end point announces itself with a sudden color change: here, molecular iodine formed from potassium iodate and sodium bisulfite turns a starch solution dark blue. In the first step, IO3− + 3HSO3− → I− + 3H+ + 3SO42−, the bisulfite ion gives up hydrogen ions, and students identify it as the acid because it is a hydrogen ion donor. — Clock Reaction (June 2026, Question 30)

Resources

Examples and discussion of resources for the learning, teaching, and assessment of HS-PS1-11.

Pixel beaver This section could be expanded upon. You can help out by adding to this section.


NGSS Dimensions

Performance expectation HS-PS1-11 was developed using the following elements from the NRC document A Framework for K-12 Science Education:

Science and Engineering Practices
  • Planning and Carrying Out Investigations
    • Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly.
    • Select appropriate tools to collect, record, analyze, and evaluate data.
Disciplinary Core Ideas
  • PS1.B: Chemical Reactions
    • (NYSED) Acids and bases play an important role in the daily lives of humans and other organisms (e.g. agricultural applications, environmental impacts (acid rain), animal and plant physiology).
Crosscutting Concepts
  • Patterns
    • Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena.
Page contributors: Conrad Richman, Caroline Leonard
Chemistry | HS. Chemical Reactions
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