Untitled Quiz

Covers 75% of Earth’s surface
97% of water on Earth is found in oceans
3% is freshwater
- 2% of water on Earth is in ice caps and glaciers
- 1% is found in lakes, underground, or in the atmosphere (usable by humans)
Makes up 70% of the human body
- 92% of blood plasma
- 80% of muscle tissues
- 60% of red blood cells

For every water molecule, two hydrogen atoms bond to one oxygen atom by a covalent bond.
Water molecules are not symmetrical
Shape resembles a widened “V”
Electrons spend more time closer to oxygen (O) and less time near hydrogen (H)

Oxygen atom is larger than hydrogen atoms, meaning oxygen atoms tend to “share” electrons more than hydrogen atoms.
Oxygen is more electronegative, so the region around oxygen has a partial negative charge.
The region around the two hydrogen atoms has a partial positive charge.
Water molecules are polar molecules, meaning opposite ends of the molecule have opposite charges.

The slightly negative regions of one water molecule are attracted to the slightly positive regions of nearby molecules.
This creates a hydrogen bond.
Hydrogen bonds hold water molecules together.
Each water molecule can form a maximum of 4 hydrogen bonds.
Hydrogen bonds are weak, about 1/20th as strong as covalent bonds.
Hydrogen bonds constantly form, break, and reform.
This provides water with its extraordinary properties

Attraction between water molecules through hydrogen bonds.
Leads to:
- Surface Tension: Attraction between water molecules at the surface of the liquid.
- High Specific Heat: Water requires a large amount of energy to warm up and a long time to cool down.
- Viscosity: Resistance to flow, caused by cohesion between molecules.

Attraction of water to other surfaces/substances.
Leads to:
- Water as a "Universal Solvent." Water only dissolves polar molecules.
- Capillary Action Water's ability to climb objects against gravity.

Solvent: substance that dissolves other substances.
Water dissolves more substances than any other natural substance.
Properties of Solvents:
- Interacts with other polar compounds
- Is repelled by non-polar compounds
- Small size allows for saturation of areas
- Can convey other substances in solutions

Movement of a substance from an area of high concentration to an area of lower concentration.

The net movement of water across a selectively permeable membrane driven by a difference in solute concentrations on the two sides of the membrane.
Water moves from the area of low solute concentration to the area of high solute concentration until equilibrium is reached.

As heat decreases, kinetic energy of molecules decreases, causing molecules to come closer together.
Most liquids become denser as they cool.
However, water becomes slightly less dense at 4°C and below.
This is because as water molecules get closer together, they begin to repel each other.
Water molecules "organize" with hydrogen bonds as it freezes, forming hexagon shapes.
The temperature of a substance is a measure of the average kinetic energy of the particles in a sample of matter.

Two systems are in thermal equilibrium only if they have the same temperature.
Two systems in thermal equilibrium with a third system are also in thermal equilibrium with each other.

Heat is thermal energy absorbed or released.
Unit of heat is the calorie (1 cal). It’s the quantity of heat required to raise the temperature of 1 g of water by 1°C.
In an enclosed system, the amount of heat lost is equal to the amount of heat gained (Conservation of Energy).

Quantity of heat required to raise the temperature of the entire body by one degree.

Amount of heat (Q) needed to raise the temperature (t) of a unit mass (m) by a unit degree.
Specific Heat Capacity formula: C = Q / (m Δt) or Q = m c Δt
Unit is cal/g °C

When a change of phase occurs, there is only a change in the potential energy of the molecules.
Temperature remains constant during the phase change.
The quantity of heat Q required to change the phase of a substance is given as Q = m L.
Latent heat (L) is the quantity of heat per unit mass needed to change a substance from one phase to another.
L = Q / m

Treatment of disease by using water at different temperatures and in different ways.
Encompasses various approaches and therapeutic methods that utilize the physical properties of water (temperature, pressure) for therapeutic purposes.
Important physical laws of water for physiotherapists to understand: buoyancy and hydrostatic pressure.
Therapeutic uses: superficial heating and cooling, wound care, water exercise, pain control, edema control.

Low impact, unlike land exercises.
Can be done even with injuries or pain.
Supportive for the body.
Reduced risk of falling.
Healing properties that aid in recovery.
Reduces swelling.
All exercises engage the whole body.
No soreness or stiffness after sessions.
Turbulence provides a massage.
Increased resistance, resulting in harder work and slower, more precise movements.
More efficient muscle use.
Great for back pain.
Safe environment, especially for those with balance problems.

Problem 1: Calculate the heat required to heat a 500g copper coffee mug and 200g of coffee from 20 °C to 96 °C.
Problem 2: Determine the mass of copper shot heated to 90°C and dropped into 80g of water at 10°C, if the equilibrium temperature is 18°C.
Problem 3: Calculate the heat needed to convert 10g of ice at -20°C to steam at 100°C.
Problem 4: Determine how much ice at 0°C must be mixed with 4g of steam at 100°C to produce water at 60°C.