Question

how can you increase the density of water?

○ increase the temperature, decrease salinity, decrease pressure
○ decrease the temperature, decrease, salinity, decrease pressure
○ increase the salinity, increase pressure, increase temperature
○ increase the pressure, increase salinity, decrease temperature

Explanation:

• Temperature: Water is densest at \(4^{\circ}C\). As temperature decreases below \(4^{\circ}C\) (but above freezing), water molecules arrange more closely (less thermal motion disrupts hydrogen - bond - based structuring in a certain range). As temperature increases, water expands (thermal expansion), so density decreases.
• Salinity: Saline water has more mass per unit volume than pure water. Dissolved salts add mass. For example, seawater (higher salinity) is denser than freshwater.
• Pressure: Applying pressure compresses water (to a small extent, since water is relatively incompressible compared to gases, but still). Compression reduces the volume \(V\) of a given mass \(m\) of water. Using the density formula \(

ho=\frac{m}{V}\), a decrease in \(V\) (with \(m\) constant) leads to an increase in \(
ho\).

Answer:

increase the pressure, increase salinity, decrease temperature