What term describes the measure of the mass of dissolved solids in a mass of water?

• A. Salinity
• B. Temperature
• C. Density
• D. pH Level

Answer: (A)

Salinity describes the amount of dissolved solids in a given mass of water. It captures how much salt and other minerals are present in that mass of water, often expressed as parts per thousand (ppt) or practical salinity units (PSU). For seawater, salinity is about 35 ppt, meaning roughly 35 grams of dissolved solids per kilogram of seawater. Temperature, density, and pH measure different properties: temperature is how hot the water is; density is mass per volume and varies with temperature and salinity; pH reflects how acidic or basic the water is. So salinity is the term that directly matches the description.