Question

1. solubility in water
2. describe how salt dissolves in water chemically.
3. what would be the ph of a solution that has 30g of salt in 500ml of water?
4. what is the difference in sea - surface salinities?
5. tropical

polar

1. what is the difference in solubility of gases in seawater?

carbon dioxide
oxygen

1. what changes the solubility of gases in water?

decreases
increases

1. describe how dissolved oxygen is used in the ocean.

Explanation:

3.

Salt dissolves in water chemically through a process called dissociation. When salt (sodium - chloride, NaCl) is added to water, the polar water molecules surround the sodium and chloride ions, pulling them apart from the salt crystal lattice and dispersing them in the water.

First, calculate the molarity of the salt solution. The molar mass of NaCl is approximately 58.5 g/mol. The number of moles of salt (n) = mass/molar - mass = 30 g/58.5 g/mol≈0.513 mol. The volume of the solution V = 500 ml = 0.5 L. Molarity (M)=n/V = 0.513 mol/0.5 L = 1.026 M. Since NaCl is a strong - electrolyte and dissociates completely in water to form Na⁺ and Cl⁻ ions, the total number of moles of ions is 2n (1 mole of NaCl gives 1 mole of Na⁺ and 1 mole of Cl⁻). But pH is related to the concentration of H⁺ or OH⁻ ions. Since NaCl is a neutral salt and does not contribute H⁺ or OH⁻ ions to the solution, the pH of the solution is 7 (assuming pure water conditions and no other acid - base impurities).

The surface salinity in tropical regions is generally higher than in polar regions. In tropical regions, high evaporation rates remove water from the surface of the ocean, leaving behind a higher concentration of salts. In polar regions, low evaporation rates, melting of ice (which adds fresh water), and high precipitation contribute to lower surface salinities.

Answer:

Salt dissolves in water chemically through dissociation, where water molecules surround and separate the ions in the salt.

4.