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MS1.

- An electrolyte is a substance that allows electricity to pass through it when dissolved in water or melted. (2)

MS2.

- Different metal ions produce different characteristic flame colors:

- Sodium ions: yellow flame (1)

- Potassium ions: lilac flame (1)

- By observing the flame color, the presence of sodium or potassium ions can be identified. (1)

MS3.

- Calculate the number of moles of sodium chloride: 10.0 g / 58.5 g/mol = 0.171 mol (1)

- Calculate the volume of solution in liters: 250 cm³ = 0.250 L (1)

- Calculate the concentration: 0.171 mol / 0.250 L = 0.684 mol/L (1)

MS4.

- SO₄²⁻ (1)

MS5.

- Barium sulfate is insoluble in water. (1)

- When sulfate ions are added to a solution containing barium ions, a white precipitate of barium sulfate forms, indicating the presence of sulfate ions. (1)

MS6.

MS7.

- Ionic bonding is the electrostatic attraction between oppositely charged ions. (1)

- Example of a compound: sodium chloride (NaCl) (1)

MS8.

- The solubility of most salts increases with increasing temperature. (1)

- This is because the kinetic energy of the water molecules increases, allowing them to break apart the ionic bonds more easily. (1)

- The exception to this is salts with low solubility, such as barium sulfate, which show little change in solubility with temperature. (1)

MS9.

- Calculate the number of moles of chloride ions in the solution: 0.20 mol MgCl₂ × 2 (chloride ions per formula unit) = 0.40 mol (1)

- Calculate the volume of solution in liters: 500 cm³ = 0.500 L (1)

- Calculate the concentration of chloride ions: 0.40 mol / 0.500 L = 0.80 mol/L (1)

MS10.

- Nitrate ions can leach into water sources, causing eutrophication and algal blooms. (1)

- Algal blooms deplete oxygen levels in water, harming aquatic life. (1)

- Nitrate ions can also contribute to the formation of harmful substances, such as N₂O, which is a greenhouse gas. (1)