Physical Science: Physical Properties of Matter

Vocabulary practice flashcards covering boiling point, cohesive forces, air pressure, and freezing/melting points from the physical science lecture notes.

Boiling Point (BP)

The temperature and pressure at which bubbles form in a liquid, occurring when the pressure inside the bubbles is equal to the atmospheric pressure outside the bubbles.

Solubility

The max amount solute that can be dissolved in a specific amount of solvent at a particular temp/pressure

Matalic CF

The CF that holds metals together where all the E- are shared between metal atoms (very strong CF because of the high melting temps)

Polar CF

The CF that refer to particles that have uneven distribution of charge (medium strength). Molecules are not symmetrical having a + end and a - end.

sugar, salt, acid, ammonia, alcohol, water are examples of what CF

Polar CF

Non-polar CF

The CF that refer to particles with an even distribution of charge symmetrical molecules

Oil, grease, fat, gasoline, wax and all gases are examples of what CF

Non-polar CF

What is rule of thumb in science

Like CF dissolve like CF

What is an emulsifier

A substance who’s molecule has a long non-polar tail and a polar head

What is solubility influenced by

Temp/pressure

Boiling Bubbles Composition

The gas of the liquid that is actively boiling.

Barometer

An instrument used to measure barometric (atmospheric) pressure.

Normal Air Pressure at Sea Level

Around $14.7\,\frac{\text{lbs}}{\text{in}^2}$ or $\text{psi}$.

Elevation vs. Air Pressure Relationship

As elevation increases, air pressure decreases ($\text{elevation} \uparrow\text{, air pressure} \downarrow$).

Boiling Point of $H_2O$ at Sea Level

$212^\circ\text{F}$ or $100^\circ\text{C}$ under normal air pressure.

Boiling Point of $H_2O$ on Mt Everest

$71^\circ\text{C}$ or $160^\circ\text{F}$, because the air pressure is so low.

Cohesive Forces (CF)

Forces between particles (atoms or molecules) that hold them together and determine how difficult a substance is to change from solid to liquid to gas.

Relationship Between Cohesive Forces and Boiling Point

In general, the stronger the cohesive forces (CF), the higher the boiling point (BP) of a substance.

Mercury ($Hg$) Cohesive Forces

Possesses strong cohesive forces, causing it to exist as a liquid at room temperature.

Oxygen ($O$) Cohesive Forces

Possesses weak cohesive forces, causing it to exist as a gas at room temperature.

Water vs. Rubbing Alcohol Boiling Points

$H_2O$ has stronger cohesive forces than rubbing alcohol, meaning water molecules move less, require a higher temperature to change from liquid to gas, and have a higher boiling point ($\text{BP } H_2O > \text{BP Alcohol}$).

Freezing Point / Melting Point

The temperature at which a substance will freeze or melt depending on the surrounding temperature (melting occurs if air is warmer than this temperature; freezing occurs if air is colder).

Freezing/Melting Point of $H_2O$

$32^\circ\text{F}$ or $0^\circ\text{C}$.

Effect of Weak Cohesive Forces on Freezing

Weak cohesive forces allow molecules to move more rather than being locked in place; therefore, temperature must be super low to slow molecules down enough for weak forces to hold them in place to form a solid.