The pH of Solution

;Dr. Lin Xiang created this module at the University of Kentucky in 2022. If you mention this model in a publication, we ask that you include the citations below.
;Xiang, L. (2022). The pH of Solution. Department of STEM Education, University of Kentucky, Lexington, KY.
;![CC BY-NC-SA 4.0](http://ccl.northwestern.edu/images/creativecommons/byncsa.png)
;This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 License.  To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/4.0/.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

breed [OHs OH]
breed [H3OS H30]
breed [legends legend]

turtles-own[ ]
globals [Num-H Num-OH]

to setup
  ca
  set-bk
  set-legends
  set-item-pH
  set-tt
  plot-ion-concentrations
  plot-ion-concentrations-log
  reset-ticks
end 

to set-bk
  ask patches [set pcolor 91.5 + random-float 0.5]
  ask patches with [ pycor = max-pycor or pycor < 4] [set pcolor 101]
  ask patches with [ pxcor = min-pxcor or pxcor = max-pxcor] [set pcolor 101]
end 

to set-tt
  set-default-shape ohs "ab-oh-1"
  set-default-shape h3os "ab-h3o-1"


  set num-H round (1000 * (1.3895 ^ (-1 * pH)))
  set num-OH round (1000 * (1.3895 ^ (-1 * (14 - pH))))



  create-h3os num-H [set-tt-properties ]
  create-ohs num-OH [set-tt-properties ]
end 

to set-tt-properties
   set size 1.75
   setxy 1 + random-float (max-pxcor - 2) 4 + random-float (max-pycor - 5)
end 

to set-legends
 create-legends 4

 ask legend 0
   [set shape "ab-oh-1"
    set size 1.75
    setxy 14 2]

  ask legend 1
  [set shape "blank"
    set size 1.5
    set label "hydroxide(OH-)"
    set label-color white
    setxy 16.8 1.2]

  ask legend 2
   [set shape "ab-h3o-1"
    set size 1.75
    setxy 26 2]

  ask legend 3
  [set shape "blank"
    set size 1.5
    set label "Hydronium (H3O+)"
    set label-color white
    setxy 30 1.2]
end 

to go
  set Choose-an-item "None" clear-output
  move
  ionization
  plot-ion-concentrations
  plot-ion-concentrations-log

  tick
end 

to move
  ask turtles with [breed != legends]    ;ask non-legend turtles
  [rt random 360                            ;rotate
    if [pcolor] of patch-at dx dy <= 92 and [pcolor] of patch-at dx dy >= 91.5    ;if the patch-ahead has the proper color
      [fd 0.5                                                                       ;move forward
       if ycor < 5 [set ycor 5]                                                   ;if ycor is low, put ycor higher
  ]]
end 

to ionization

  set num-H round (1000 * (1.3895 ^ (-1 * pH)))
  set num-OH round (1000 * (1.3895 ^ (-1 * (14 - pH))))

  let current-H count H3Os
  let current-OH count OHs

  (ifelse
    num-H > current-H
     [create-h3os abs (num-H - current-H) [set-tt-properties set color 82.5]]
    num-H < current-H
    [ask n-of abs (num-H - current-H) h3os [die]])

   (ifelse
    num-OH > current-OH
    [create-ohs abs (num-OH - current-OH) [set-tt-properties set color 82.5]]
    num-OH < current-OH
    [ask n-of abs (num-OH - current-OH) OHs [die]])
end 

to plot-ion-concentrations ;; this creates the bar graph

    set-current-plot "Ion Concentrations"
    clear-plot
    set-plot-x-range 0 1
    set-plot-y-range 0 0.01
    plot-pen-down
    set-current-plot-pen "Hydronium (H3O)"
    plotxy 0 10 ^ (-1 * ph)
    set-current-plot-pen "Hydroxide (OH)"
    plotxy 1 10 ^ (-1 * (14 - ph))
end 

to plot-ion-concentrations-log ;; this creates the bar graph

    set-current-plot "Negative log of Ion Concentrations"
    clear-plot
    set-plot-x-range 0 1
    set-plot-y-range 0 14
    plot-pen-down
    set-current-plot-pen "pH"
    plotxy 0 ph
    set-current-plot-pen "pOH"
    plotxy 1 (14 - ph)
end 

to set-item-pH
(ifelse
Choose-an-item = "None"
    [set ph ph
      output-print "Use the model in two ways:"
      output-print ""
      output-print "1. Select an item from the list, then"
      output-print ""
      output-print "click the set up button to view"
      output-print ""
      output-print "the concentrations of H3O+ and OH-."
      output-print ""
      output-print "2. Run the model and change the ph"
      output-print ""
      output-print "slider to view the general relative"
      output-print ""
      output-print "concentrations of H3O+ and OH-."

    ]
Choose-an-item = "Hydrochloric Acid(1M)"
    [
      set ph 0
      output-print "Hydrochloric acid (HCl) is the "   ;cite from https://www.chemicalsafetyfacts.org/chemicals/hydrochloric-acid/
      output-print ""
      output-print "aqueous solution of hydrogen "
      output-print ""
      output-print "chloride gas and the main component"
      output-print ""
      output-print "of gastric acid, an acid produced "
      output-print ""
      output-print "naturally in the human stomach to "
      output-print ""
      output-print "help digest food. Hydrochloric acid "
      output-print ""
      output-print "is synthetically produced for a "
      output-print ""
      output-print "variety of industrial and commercial "
      output-print ""
      output-print "applications. HCl is corrosive."
      output-print ""
      output-print "Personal protective equipment"
      output-print ""
      output-print "such as vapor respirators,"
      output-print ""
      output-print "rubber gloves, splash goggles and"
      output-print ""
      output-print "and face shields when handling HCl."
      output-print ""
      output-print "  --Chemistrysafetyfacts.org"
    ]

Choose-an-item = "Battary acid"
    [
      set ph 0.8
      output-print "Battery acid is the acid used in"   ;cite from https://www.chemicals.co.uk/blog/what-is-battery-acid
      output-print ""
      output-print "rechargeable lead-acid batteries,"
      output-print ""
      output-print "like the ones used in cars."
      output-print ""
      output-print "Battery acid is made of sulphuric"
      output-print ""
      output-print "acid that has been deluted to a"
      output-print ""
      output-print "concentration of about 30-50%."
      output-print ""
      output-print "In this context, battery acid has "
      output-print ""
      output-print "an acidic pH of 0.8, which is highly"
      output-print ""
      output-print "corrosive. Therefore,it needs to be"
      output-print ""
      output-print "handled with caution."
      output-print ""
      output-print "--www.chemicals.co.uk/blog/what-"
      output-print ""
      output-print "is-battery-acid"
    ]

Choose-an-item = "Stomach acid"
    [set ph 1.5
      output-print "Stomach acid, or gastric acid, is"   ;cite from https://www.healthline.com/health/how-strong-is-stomach-acid
      output-print ""
      output-print "produced by our stomach's lining."
      output-print ""
      output-print "Stomach acid has a pH between 1"
      output-print ""
      output-print "and 2. This very acidic liquid"
      output-print ""
      output-print "helps break down food for earlier"
      output-print ""
      output-print "digestion. It also helps defend"
      output-print ""
      output-print "against pathogens and microbes"
      output-print ""
      output-print "that could make us sick."
      output-print ""
      output-print "Stomach acid’s low pH level is"
      output-print ""
      output-print "largely due to hydrochloric acid."
      output-print ""
      output-print ""
      output-print "--www.healthline.com/health/how-"
      output-print ""
      output-print "strong-is-stomach-acid"
    ]

Choose-an-item = "Lemon juice"
    [set ph 2
      output-print "Lemon juice in its natural state"  ;cite from https://www.thoughtco.com/the-ph-of-lemon-juice-608890
      output-print ""
      output-print "has a pH ranging from 2 to 3,"
      output-print ""
      output-print "because lemons contain citric"
      output-print ""
      output-print "acid and ascorbic acid, also"
      output-print ""
      output-print "known as vitamin C."
      output-print ""
      output-print "Lemons are not only acidic but"
      output-print ""
      output-print "also contain a surprisingly high"
      output-print ""
      output-print "amount of natural sugars, so"
      output-print ""
      output-print "dentists typically caution"
      output-print ""
      output-print "patients about eating them"
      output-print ""
      output-print "as biting into lemons can "
      output-print ""
      output-print "damage tooth enamel."
      output-print ""
       output-print ""
      output-print "--www.thoughtco.com/the-ph-of-"
      output-print ""
      output-print "lemon-juice-608890"
    ]

Choose-an-item = "Vinegar"
    [set ph 2.5
      output-print "Vinegar’s pH level varies based"       ;cite from https://www.healthline.com/health/ph-of-vinegar
      output-print ""
      output-print "upon the type of vinegar it is."
      output-print ""
      output-print "White distilled vinegar, the"
      output-print ""
      output-print "kind best suited for household"
      output-print ""
      output-print "cleaning, typically has a pH"
      output-print ""
      output-print "of around 2.5. Through a two-part"
      output-print ""
      output-print "fermentation process, yeast and"
      output-print ""
      output-print "bacteria are used to turn the"
      output-print ""
      output-print "sugar into ethanol (ethyl alcohol),"
      output-print ""
      output-print "which is then processed into"
      output-print ""
      output-print "acetic acid. It is the acetic acid"
      output-print ""
      output-print "in vinegar that makes it acidic."
      output-print ""
       output-print ""
      output-print "--www.healthline.com/health/"
      output-print ""
      output-print "ph-of-vinegar"
    ]

Choose-an-item = "Coke and Pepsi"
    [set ph 2.5
      output-print "Coke and Pepsi have a pH of 2.5,"       ;cite from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4808596/
      output-print ""
      output-print "which is mainly due to the"
      output-print ""
      output-print "phosphoric acid is added to cola "
      output-print ""
      output-print "drinks to impart tartness, reduce"
      output-print ""
      output-print "growth of bacteria and fungi,"
      output-print ""
      output-print "and improve shelf-life. "
      output-print ""
      output-print "The acidities of Coke and Pepsi"
      output-print ""
      output-print "are comparable to white vinegar."
      output-print ""
       output-print ""
      output-print "--www.ncbi.nlm.nih.gov/pmc/articles"
      output-print ""
      output-print "/PMC4808596/"
    ]

Choose-an-item = "Tomato"
    [set ph 4.3
      output-print "Tomatoes are acidic in nature."           ; cite from https://techiescientist.com/ph-of-tomato/
      output-print ""
      output-print "The pH of fresh tomatoes is in"
      output-print ""
      output-print "the range of 4.3 – 4.9. Different"
      output-print ""
      output-print "forms of tomato products will"
      output-print ""
      output-print "have different pH because of the"
      output-print ""
      output-print "additives added as well as the"
      output-print ""
      output-print "cooking process. The pH for canned"
      output-print ""
      output-print "tomatoes, in the range of 3.5-4.7,"
      output-print ""
      output-print "is lower as compared to the fresh"
      output-print ""
      output-print "tomato because of the preservation"
      output-print ""
      output-print "agent added to make increase its"
      output-print ""
      output-print "shelf life. For tomato puree and"
      output-print ""
      output-print "juice, the pH ranges between 4.1-4.6."
      output-print ""
      output-print ""
      output-print "--Techiescientist.com/ph-of-tomato/"
    ]

Choose-an-item = "Acid rain"
    [set ph 4.3
      output-print "Acid rain is caused by the release"            ; Cite from https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/2020-01/bb-8.pdf
      output-print ""
      output-print "of sulfur dioxide and nitrogen "
      output-print ""
      output-print "oxides into the atmosphere, where "
      output-print ""
      output-print "they react with water, oxygen, and "
      output-print ""
      output-print "other chemicals to become sulfuric"
      output-print ""
      output-print "and nitric acid respectively. The pH"
      output-print ""
      output-print "and acid rain is generally below 4.5."
      output-print ""
      output-print "Acid rain can be formed by natural"
      output-print ""
      output-print "causes, such as volcanic eruptions."
      output-print ""
      output-print "More commonly,however, acid rain is"
      output-print ""
      output-print "due to human activities. Burning"
      output-print ""
      output-print "fossil fuels, manufacturing, oil"
      output-print ""
      output-print "refineries, electricity generation,"
      output-print ""
      output-print "and vehicles all release sulfur and"
      output-print ""
      output-print "nitrogen oxides into the atmosphere."
      output-print ""
      output-print ""
      output-print "--www.des.nh.gov"
    ]

Choose-an-item = "Black coffee"
    [set ph 5
      output-print "The pH values of the cold and hot"                    ;cite from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6207714/
      output-print ""
      output-print "brew samples were found to range"
      output-print ""
      output-print "from 4.85 to 5.13."
      output-print ""
      output-print "The brewing process releases acids"
      output-print ""
      output-print "from coffee beans, giving coffee a"
      output-print ""
      output-print "acidic pH."
      output-print ""
      output-print ""
      output-print "--www.ncbi.nlm.nih.gov/pmc/articles"
      output-print ""
      output-print "/PMC6207714/"
    ]

Choose-an-item = "Clean rain"
    [set ph 5.6
      output-print "Uncontaminated precipitation is"      ; Cite from https://www.des.nh.gov/sites/g/files/ehbemt341/files/documents/2020-01/bb-8.pdf
      output-print ""
      output-print "naturally acidic. Water contains"
      output-print ""
      output-print "atmospheric gases as well as"
      output-print ""
      output-print "carbon dioxide, and when the"
      output-print ""
      output-print "carbon dioxide dissolves it forms"
      output-print ""
      output-print "carbonic acid, which makes the"
      output-print ""
      output-print "pH of normal rain about a 5.6"
      output-print ""
      output-print "on the pH scale. "
      output-print ""
      output-print ""
      output-print "--www.des.nh.gov"

    ]
Choose-an-item = "Milk"
    [set ph 6.6
      output-print "Milk is slightly acidic or close"       ;cite from https://www.thoughtco.com/what-is-the-ph-of-milk-603652
      output-print ""
      output-print "to neutral pH. The pH of a glass"
      output-print ""
      output-print "of cow milk ranges from 6.4 to "
      output-print ""
      output-print "6.8. Milk fresh from the cow"
      output-print ""
      output-print "typically has a pH between 6.5"
      output-print ""
      output-print "and 6.7. This is because it "
      output-print ""
      output-print "contains lactic acid. The pH of"
      output-print ""
      output-print "milk changes over time. As milk"
      output-print ""
      output-print "goes sour, it becomes more"
      output-print ""
      output-print "acidic and the pH gets lower."
      output-print ""
      output-print ""
      output-print "--www.thoughtco.com/what-is-"
      output-print ""
      output-print "the-ph-of-milk-603652"
    ]

Choose-an-item = "Distilled water"
    [set ph 7
      output-print "The process for distillation"        ;Cite from https://sciencing.com/ph-distilled-water-4623914.html
      output-print ""
      output-print "involves boiling the water,"
      output-print ""
      output-print "allowing the steam to condense"
      output-print ""
      output-print "in a tube and collecting the"
      output-print ""
      output-print "condensation in a container."
      output-print ""
      output-print "Sophisticated distillation"
      output-print ""
      output-print "techniques may produce water"
      output-print ""
      output-print "free of any solutes. If you"
      output-print ""
      output-print "measure the pH of distilled water"
      output-print ""
      output-print "immediately after distillation,"
      output-print ""
      output-print "the pH is 7. But, it soon changes"
      output-print ""
      output-print "as it absorbs CO2 from air."
      output-print ""
      output-print ""
      output-print "--sciencing.com/ph-distilled-"
      output-print "water-4623914.html"
    ]

Choose-an-item = "Blood"
    [set ph 7.4
      output-print "The pH of blood in the arteries"     ;Cite from https://www.medicalnewstoday.com/articles/ph-of-blood
      output-print ""
      output-print "should be between 7.35 and 7.45"
      output-print ""
      output-print "for the body’s metabolic processes"
      output-print ""
      output-print "and other systems to work well."
      output-print ""
      output-print "Certain situations and medical"
      output-print ""
      output-print "conditions can occur if the blood"
      output-print ""
      output-print "pH is lower than 7.35 or higher"
      output-print ""
      output-print "than 7.45. The human body has a"
      output-print ""
      output-print "complex system of feedback and"
      output-print ""
      output-print "regulation to maintain this"
      output-print ""
      output-print "healthy pH levels."
      output-print ""
      output-print ""
      output-print "--www.medicalnewstoday.com/"
      output-print "articles/ph-of-blood"
    ]

Choose-an-item = "Sea water"
    [set ph 8.1
      output-print "Prior to the Industrial Revolution,"            ;Cite from https://www.epa.gov/ocean-acidification/understanding-science-ocean-and-coastal-acidification
      output-print ""
      output-print "average ocean pH was about 8.2."
      output-print ""
      output-print "Today, average ocean pH is about"
      output-print ""
      output-print "8.1. This might not seem like"
      output-print ""
      output-print "much of a difference, but the"
      output-print ""
      output-print "relationship between pH and acidity"
      output-print ""
      output-print "is not direct. Each decrease of one"
      output-print ""
      output-print "pH unit is a ten-fold increase in"
      output-print ""
      output-print "acidity. This means that the acidity"
      output-print ""
      output-print "of the ocean today, on average, is"
      output-print ""
      output-print "about 25% greater than it was"
      output-print ""
      output-print "during preindustrial times."
      output-print ""
      output-print ""
      output-print "--www.epa.gov/ocean-acidification/"
      output-print "understanding-science-ocean-and-"
      output-print "coastal-acidification"
    ]

Choose-an-item = "Baking soda"
    [set ph 8.3
      output-print "Baking soda, also known as sodium"   ; Cite from https://pubchem.ncbi.nlm.nih.gov/compound/Sodium-Bicarbonate
      output-print ""
      output-print "bicarbonate appears as odorless"
      output-print ""
      output-print "white crystalline powder or lumps."
      output-print ""
      output-print "Baking soda has a pH of 8.3 if"
      output-print ""
      output-print "freshly prepared 0.1 molar aqueous"
      output-print ""
      output-print "solution. Baking soda is often"
      output-print ""
      output-print "used to make buffer and in"
      output-print ""
      output-print "many cleansing solutions."
      output-print ""
      output-print ""
      output-print "--pubchem.ncbi.nlm.nih.gov/compound"
      output-print "/Sodium-Bicarbonate"
    ]

Choose-an-item = "Milk of magnesia"
    [set ph 10.5
      output-print "Milk of magnesia is made from "     ;Cite from https://www.healthgrades.com/right-care/digestive-health/milk-of-magnesia; ph from chem.libretexts.org/
      output-print ""
      output-print "magnesium hydroxide, a chemical "
      output-print ""
      output-print "compound present in a naturally  "
      output-print ""
      output-print "occurring mineral called brucite."
      output-print ""
      output-print "Milk of magnesia is an alkaline"
      output-print ""
      output-print "mineral and can neutralize stomach"
      output-print ""
      output-print "acid. It is meant for occasional, "
      output-print ""
      output-print "short-term use to help with"
      output-print ""
      output-print "certain digestive problems."
      output-print ""
      output-print ""
      output-print "--www.healthgrades.com/right-care/"
      output-print "digestive-health/milk-of-magnesia"
    ]

Choose-an-item = "Ammonia solution"
    [set ph 12
      output-print "Aqua ammonia (ammonium hydroxide) is"    ; Cite from https://airgasspecialtyproducts.com/wp-content/uploads/2016/02/Physical_Properties-1.pdf
      output-print ""
      output-print "classified as a weak base."
      output-print ""
      output-print "It ionizes much less completely"
      output-print ""
      output-print "in water than does a strong"
      output-print ""
      output-print "base such as sodium hydroxide."
      output-print ""
      output-print "Typically, the pH of an ammonia"
      output-print ""
      output-print "solution will be between 11 and"
      output-print ""
      output-print "12, compared with a pH of about"
      output-print ""
      output-print "14 for sodium hydroxide solutions."
      output-print ""
      output-print "Aqua ammonia is a clear, colorless"
      output-print ""
      output-print "liquid having a strong pungent"
      output-print ""
      output-print "ammonia odor."
      output-print ""
      output-print ""
      output-print "--airgasspecialtyproducts.com/"
      output-print "wp-content/uploads/2016/02/"
      output-print "Physical_Properties-1.pdf"
    ]

Choose-an-item = "Bleach"
    [set ph 13
      output-print "Bleach is an alkali. The pH value"       ; Cite from https://techiescientist.com/is-bleach-an-acid-or-base/
      output-print ""
      output-print "of sodium hypochlorite ranges between"
      output-print ""
      output-print "11 and 13. In an aqueous solution,"
      output-print ""
      output-print "it dissociates into hypochlorite"
      output-print ""
      output-print "anion and sodium ions. The"
      output-print ""
      output-print "hypochlorite ions formed to accept"
      output-print ""
      output-print "a proton from water thereby causing"
      output-print ""
      output-print "the release of OH- ions in the"
      output-print ""
      output-print "solution, thus, making the solution"
      output-print ""
      output-print "basic."
      output-print ""
      output-print ""
      output-print "--techiescientist.com/is-bleach-an-acid-or-base/"
    ]

Choose-an-item = "Sodium Hydroxide(1M)"
    [set ph 14
      output-print "Sodium hydroxide (NaOH), also called"               ;Cite from https://www.britannica.com/science/sodium-hydroxide
      output-print ""
      output-print "caustic soda or lye, a corrosive"
      output-print ""
      output-print "white crystalline solid that contains"
      output-print ""
      output-print "the Na+ (sodium) cation and the"
      output-print ""
      output-print "OH− (hydroxide) anion. Sodium hydroxide"
      output-print ""
      output-print "is the most widely used industrial"
      output-print ""
      output-print "alkali and is often used in drain and"
      output-print ""
      output-print "oven cleaners. It is highly corrosive"
      output-print ""
      output-print "to animal and vegetable tissue."
      output-print ""
      output-print "Contact may severely irritate skin, "
      output-print ""
      output-print "eyes, and mucous membranes."
      output-print ""
      output-print ""
      output-print "--www.britannica.com/science/"
      output-print "sodium-hydroxide"
    ]

    )
end