Chem 1

Question 1

Antacid medicines- what they contain how they work/react with gastric

Answer 1

Calcium carbonate (CaCO₃), magnesium carbonate (MgCO₃), aluminium hydroxide [Al(OH)₃], and magnesium hydroxide [Mg(OH)₂].

React with gastric acid (HCl), neutralizing excess acidity.
Forms water and salts, thus raising pH of gastric juice.

Question 2

Protein solubility: isoelectric point- what it is, how it influences the solubility of membranes

Answer 2

The isoelectric point (pI) = pH at which a protein has no net charge, causing its solubility to be lowest.
Below pI, proteins gain a +ve charge, and above it, they gain a -ve charge, influencing their interactions and solubility in solutions.

Question 3

3. Uric acid and oxalic acid solubility regarding the pH and the solubility of their salts

Answer 3

Uric acid is poorly soluble in water but dissolves better in an alkaline (forms soluble urates).

Oxalic acid dissolves more easily in acidic conditions (forms soluble oxalates). In neutral or basic conditions, it forms poorly soluble calcium oxalate, can lead to kidney stones.

Question 4

Different types of necrosis caused by strong acids and bases.

Answer 4

Strong bases cause liquefactive necrosis (tissue dissolution)
Strong acids cause coagulative necrosis (tissue hardening).
- 30% hydrogen peroxide (perhydrol) reacts with skin, causing white necrotic patches due to its strong oxidative properties
Forms foam as catalase breaks down H₂O₂ into oxygen and water.

Question 5

5. Indicators used in the process of titration, different types of titration, colour changes of the indicators regarding the changes of solution pH.

Answer 5

Common indicators
Methyl orange (red in acidic to yellow in basic pH)
Phenolphthalein (colorless in acidic to pink in basic pH).
Titration methods = acid-base titration, where the color change indicates the point of neutralization.