Podcast
Questions and Answers
What role do properly balanced acid and base concentrations NOT play in biological systems?
What role do properly balanced acid and base concentrations NOT play in biological systems?
- Facilitating enzyme activity
- Supporting the synthesis of biopharmaceutical medicines
- Altering the rate of nuclear decay (correct)
- Ensuring optimal protein function
Which of the following chemical equations represents the behavior of an acid in water?
Which of the following chemical equations represents the behavior of an acid in water?
- $NaCl \rightarrow Na^+ + Cl^-$
- $NaOH \rightarrow Na^+ + OH^-$
- $HCl + H_2O \rightarrow H_3O^+ + Cl^-$ (correct)
- $H_2O \rightarrow H^+ + OH^-$
Which statement accurately describes the behavior of a base in an aqueous solution?
Which statement accurately describes the behavior of a base in an aqueous solution?
- It accepts electrons, increasing the concentration of hydronium ions.
- It accepts protons, increasing the concentration of hydroxide ions. (correct)
- It donates protons, increasing the concentration of hydronium ions.
- It donates electrons, decreasing the concentration of hydroxide ions.
Why is it important to remember that hydrogen ions (H+) do not exist independently in water?
Why is it important to remember that hydrogen ions (H+) do not exist independently in water?
What happens to the concentration of hydroxide ions (OH-) in water when the concentration of hydronium ions (H3O+) increases?
What happens to the concentration of hydroxide ions (OH-) in water when the concentration of hydronium ions (H3O+) increases?
What is the significance of the water dissociation constant ($K_w$) in the context of acid-base chemistry?
What is the significance of the water dissociation constant ($K_w$) in the context of acid-base chemistry?
Which of the following is a property that is generally associated with acids?
Which of the following is a property that is generally associated with acids?
If a solution has a higher concentration of hydroxide ions (OH-) than hydronium ions (H3O+), how is the solution classified?
If a solution has a higher concentration of hydroxide ions (OH-) than hydronium ions (H3O+), how is the solution classified?
What occurs when an acid reacts with a base?
What occurs when an acid reacts with a base?
What characterizes pure water in terms of its ion composition and pH?
What characterizes pure water in terms of its ion composition and pH?
What is the range of the pH scale?
What is the range of the pH scale?
The term 'pouvoir hydrogene' refers to what concept?
The term 'pouvoir hydrogene' refers to what concept?
What is the pH of a solution with a hydronium ion concentration of $1 \times 10^{-7}$ M?
What is the pH of a solution with a hydronium ion concentration of $1 \times 10^{-7}$ M?
Which of the following pH values indicates that a solution is acidic?
Which of the following pH values indicates that a solution is acidic?
What is the pH of a solution if the hydronium ion concentration [H+] is 1.4 x $10^{-5}$ M?
What is the pH of a solution if the hydronium ion concentration [H+] is 1.4 x $10^{-5}$ M?
Why is it important to calibrate a pH meter before use?
Why is it important to calibrate a pH meter before use?
What are pH buffers used for when measuring pH?
What are pH buffers used for when measuring pH?
In what industry is pH monitoring NOT typically crucial?
In what industry is pH monitoring NOT typically crucial?
Which application relies on maintaining specific pH levels to ensure product efficacy and prevent microbial contamination?
Which application relies on maintaining specific pH levels to ensure product efficacy and prevent microbial contamination?
In the context of acid-base chemistry, what is a 'proton acceptor'?
In the context of acid-base chemistry, what is a 'proton acceptor'?
What is the chemical formula of acetic acid?
What is the chemical formula of acetic acid?
What properties are associated with bases?
What properties are associated with bases?
Which of the following statements is true regarding bases?
Which of the following statements is true regarding bases?
Which of the following statements accurately describes the relationship between hydronium and hydroxide ions in pure water?
Which of the following statements accurately describes the relationship between hydronium and hydroxide ions in pure water?
Which of the following statements accurately describes the role of pH in the food and pharmaceutical industry?
Which of the following statements accurately describes the role of pH in the food and pharmaceutical industry?
Flashcards
Acids
Acids
Substances that donate protons (H+ ions) in chemical reactions.
Bases
Bases
Substances that accept protons (H+ ions) or release hydroxide ions in a solution.
Hydronium ion (H3O+)
Hydronium ion (H3O+)
The combination of a hydrogen ion and a water molecule
pH
pH
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Acidic solution
Acidic solution
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Basic solution
Basic solution
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Neutral Solution
Neutral Solution
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Acidic Water
Acidic Water
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Basic Water
Basic Water
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Water Dissociation Constant (Kw)
Water Dissociation Constant (Kw)
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pH Calibration
pH Calibration
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PH Applications
PH Applications
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Study Notes
- Level 6 Certificate in Food Science and Technology provided by Megan Kelly at [email protected].
- The session focuses on pH, acids, and bases.
Learning Objectives
- Learn to write the chemical equations for acids and bases.
- Learn to write chemical equations in water to show formation of acids and bases.
- Learn to define when water is acidic or basic.
- Learn to calculate acid and base concentrations using the pH scale.
- Learn to use the pH scale to determine if a water solution is acidic or basic.
- Learn about key calibration buffers of a pH meter.
Importance of Acids and Bases
- Essential in biology.
- Incorrect acid or base concentration impacts proteins and enzymes.
- Proteins and enzymes will not function.
- Biopharmaceutical medicines cannot be made.
Common Acids
- Hydrochloric Acid (HCI).
- Nitric Acid (ΗΝΟ3).
- Phosphoric Acid (H3PO4).
- Sulfuric Acid (H2SO4).
- Acetic Acid (CH3COOH).
Acids and Bases Chemical Reactions
- Acids and bases chemical reactions create an acid or base in aqueous solutions in water.
- Acid: HCI + H₂O → H₃O+ + Cl-.
- Base: NaOH + H₂O → Na + OH-.
- Acids donate protons(H+ ions) in a chemical reaction.
- Bases accepts protons (H+ ions) or releases hydroxide ions in a solution.
Acids in Water
- Acids make H₃O+ in water.
- H+ in water does not exist by itself.
- If H+ is in water it must make hydronium ion.
- Hydronium ion is made by adding H+ to H₂O to make H₃O+.
- Water receiving H+ is classified as a base.
- Base is a proton acceptor.
- The combination of a hydrogen ion and a water molecule forms H₃O+.
Water Dissociation Constant
- Kw value remains a constant.
- If H+ increases, then OH- decreases.
- If OH- increases, then H+ decreases.
- Normally, H+ and OH- = 1.0x10-7.
- Kw = [H3O+][OH-] = [H+][OH-] = 1.0 × 10⁻¹⁴.
Properties of Acids
- H+ ions are produced when dissolved in water.
- Acids exist in ionic form in solutions.
- Acids are known for their sour taste.
- Acids can corrode metals upon contact.
Acids as Proton Donors
- Increase hydronium ions like H3O+.
- HCI (I) H3O+ (aq) + Cl-(aq) means more [H3O+] than normally in water.
- [H3O+] > 1 x 10-7M
- When H3O+ increases, OH- decreases.
- Water is now acidic.
Properties of Bases
- Serve as proton acceptors to produce OH- ions in water.
- Exist as ions in solution.
- Bases are typically bitter with a chalky taste.
- Bases are feel soapy and slippery to the touch.
Bases
- Increase the hydroxide ions (OH-).
- NaOH (s) converts to Na+(aq) + OH-(aq), means more [OH-] than in water.
- [OH-] > 1 x 10-7M.
- When OH- increases, H3O+ decreases.
- Water is now basic.
Acidity and Basicity
- Water is acidic if [H3O+] > 1 x 10-7M.
- Water is basic if [OH-] > 1 x 10-7M.
- When acid reacts with a base a salt is formed.
Pure Water
- Pure water contains small but equal amounts of ions of H3O+ and OH-.
- H2O + H2O <==> H3O+ + hydrodium and OH- + hydroxide.
- 1 x 10-7 level.
Water Acidity Range
- In water acid concentration can range from 1 to 14.
- pH = - log [H+].
- "pH" called pouvoir hydrogene (“hydrogen power" or power of hydrogen) is expressed from 0 to 14, and in a log value.
pH Scale
- A pH from 0-6 is represents acidic, 7 is neutral and 8-14 is alkaline.
pH Calculations
- Solution is acidic for pH 3 and 5.
- Solution is neutral at pH 7.
- Solution is basic when pH is 9 and 12.
- To calculate pH given [H+] = -log10[H+].
- For example [H+] = 1.4 x 10-5 M, the pH = -log10(1.4 x 10-5) = 4.85.
Measuring PH
- Measurement can be made with a meter.
- Ensure to calibrate as the electrode is fragile.
- Use aqueous water buffers to calibrate with a specific pH value.
Applications of pH in Food and Pharma
- pH affects the quality, stability, solubility and efficacy of pharmaceutical products.
- Monitoring potential for microbial growth in dairy manufacturing.
- Used to monitor quality of water.
- Used in rinse tests for cleaning.
- Plays a crucial role in beer and wine production.
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