Chapter 4: The Physical Properties of Water Flashcards

Flashcards based on lecture notes covering the physical properties of water, including its structure, temperature, heat, density, and energy transmission.

What are the components of an atom's nucleus?

Protons (positive charge) and Neutrons (no charge), collectively known as nucleons.

Describe the structure of a water molecule.

A water molecule (H2O) consists of two hydrogen atoms and one oxygen atom connected by covalent bonds.

What type of bond exists between water molecules?

Hydrogen bonds, which are weaker interactions between the poles of water molecules.

Distinguish between temperature and heat.

the average kinetic energy of atoms/molecules in a substance

total kinetic energy.

List the three phases of matter for water.

Solid (ice), Liquid (water), and Gas (water vapor).

Define Density

Density is mass divided by volume (Density = Mass / Volume).

What is relative humidity?

The amount of moisture (in liquid form) in the air.

What is dew point?

The temperature at which water saturation occurs.

Define latent heat of fusion.

The amount of energy required for the phase change between liquid and solid.

Define latent heat of vaporization.

The amount of energy required for the phase change between liquid and gas.

Does temperature change during changes of state?

No, temperature does NOT change during phase change; only the molecular arrangement is changing.

Define specific heat.

The amount of energy needed to change the temperature of 1 g of a substance by 1 °C.

Why is water's high specific heat important for life?

Provides temperature stability and supports biological processes.

What is heat capacity?

The amount of heat needed for a unit change in temperature for the entire substance.

Define cohesion in the context of water.

The tendency for water molecules to stick together due to hydrogen bonds.

Define surface tension.

How hard it is to stretch or penetrate the surface of a liquid.

Define viscosity

Resistance to flow.

What is the density of pure water at 4 °C?

1 g/cm3

How does pressure affect density of water?

Water is nearly incompressible, so pressure doesn’t really affect density.

How does temperature affect the density of water?

Warmer temperature results in lower density, colder temperature results in higher density; highest density at 4 °C.

Why does ice float in liquid water?

Ice is less dense than liquid water due to its lattice structure which increases its volume.

How does salinity affect density?

Increased salinity increases density.

What are the three modes of energy transmission by heat?

Conduction, Convection, and Radiation.

What is attenuation?

Decrease in intensity with distance.

Describe Beer's Law.

Used to find light intensity at particular depth (z) using the equation: 𝐼z=𝐼0e−kz

What affects light attenuation in water?

Turbidity, presence of microorganisms, pollution, and wavelength of light.

How does the wavelength of light affect its attenuation in water?

Very short and long wavelengths (UV and red) are absorbed quickly, while blues are not.

What is a Secchi disk used for?

Measuring light attenuation in water.

How does the speed of sound in Water compare to the speed of sound in air?

Sound travels faster in water than air: 1500m/s vs. 334m/s

How does temperature, salinity, and depth affect the speed of sound in water?

The speed of sound increases with higher temperature, salinity, and depth.

What is sonar?

Using sound waves to find things.

What is the SOFAR zone?

SOund Fixing And Ranging – 1000m down. Where sound doesn’t escape due to salinity, temperature, and pressure – keeps bouncing around.