TEAS 3.5 Properties of Solutions

What is a polar molecule?

A molecule with distinct charges on different ends (oxygen end is negative, hydrogen end is positive)

What type of bonds does water form between molecules?

Hydrogen bonds

What is cohesion?

The tendency of similar molecules to stick together or group together

What is adhesion?

A measure of how well dissimilar particles or surfaces cling to one another

What is the boiling point of water?

100°C (212°F)

Why does ice float on water?

Ice has lower density than liquid water

Why is water called the universal solvent?

Many substances dissolve in water due to its polarity

What is a solution?

A homogeneous mixture of two or more substances uniformly distributed at the microscopic level

What is a solvent?

The substance in which a solute dissolves to form a solution (present in greater proportion)

What is a solute?

The substance that dissolves in a solvent to form a solution (present in lesser proportion)

Is forming a solution a chemical or physical process?

Physical process - no chemical transformation occurs

What determines the overall phase of a solution?

The phase of the solvent

What does hydrophilic mean?

Water-loving; solutes that dissolve well in water

What does hydrophobic mean?

Water-fearing; solutes that don't dissolve well in water

How does temperature affect the solubility of solid and liquid solutes?

Solubility increases with increasing temperature

How does temperature affect the solubility of gas solutes?

Solubility decreases with increasing temperature

What is an unsaturated solution?

A solution containing less than the maximum amount of solute that can dissolve

What is a saturated solution?

A solution containing the maximum possible amount of solute at a given temperature

What is a supersaturated solution?

A solution produced at higher temperatures that contains more solute than would normally dissolve at lower temperatures

What is concentration?

The quantity of solute in a given quantity of solution

What is dilution?

The addition of solvent to decrease the concentration of solute in a solution

What is the formula for molarity?

Moles of solute ÷ liters of solution (mol/L)

What is the formula for molality?

Moles of solute ÷ kg of solvent (mol/kg)

What is the formula for mole fraction?

Moles of solute ÷ total moles present (mol/mol)

What is the formula for mass percentage?

(Mass of solute [g] ÷ mass of solution [g]) × 100

When are parts per million (ppm) used?

To express very low concentrations such as residual impurities or pollutants

Is molarity temperature dependent or independent?

Temperature dependent

Are molality, mole fraction, and mass percentage temperature dependent?

Temperature independent

What is diffusion?

The movement of any substance from areas of high concentration to areas of low concentration

What is osmosis?

A specific type of diffusion where water moves across a semipermeable membrane from an area of high concentration to an area of low concentration

What are aquaporins?

Protein pores in cell membranes through which water moves passively

In osmosis, does water move toward areas of higher or lower solute concentration?

Higher solute concentration (where solvent concentration is lower)

Give an example of diffusion.

Perfume molecules spreading throughout a room, or carbon dioxide moving from blood capillaries to lung alveoli

Give an example of osmosis.

Water flowing into plant root cells that contain dissolved minerals, sugars, and salts

What is passive transport?

Movement from high concentration to low concentration that requires no energy (only kinetic energy of moving molecules)

What is active transport?

Movement across a cell membrane that travels against the concentration gradient and requires energy

Does diffusion require energy?

No, it is passive transport

Does osmosis require energy?

No, it is passive transport

Does active transport require energy?

Yes, usually ATP

What allows water to travel through small capillaries without using energy?

Cohesiveness of water molecules

What is surface tension?

A tight-knit layer of water molecules on the surface of any body of water created by cohesiveness

Why does water have high specific heat and high heat of vaporization?

Breaking the multitude of hydrogen bonds between water molecules requires a lot of energy

What type of vitamins are water-soluble?

Vitamins with hydrophilic structures

What type of vitamins are fat-soluble?

Vitamins with hydrophobic structures

In what direction does passive transport move substances?

From high concentration to low concentration (down the concentration gradient)

In what direction does active transport move substances?

From low concentration to high concentration (against the concentration gradient)

What is the purpose of active transport?

Allows cells to accumulate substances they need even when those substances are more concentrated inside the cell than outside`;