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49 Cards in this Set
- Front
- Back
Evaporation |
Transformation of a substance from liquid to gas |
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Molarity |
The number of moles of solute per liter of solution |
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Water's greatest density |
4 C |
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Solute |
The substance that is dissolved |
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Daltons in a g Avogadro's number |
6.02 6.02 x 10 |
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Joule (J) |
1 J = 0.239 cal 1 cal = 4.184 J |
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Water has a _______ bond and is a ___________ molecule |
Polar Covalent Bond Polar molecule (O = d- , H= d+) |
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Hydrophobic |
Nonionic and nonpolar (or otherwise cannot form hydrogen bonds). Actually seem to repel water. |
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Unique features of ice |
It floats in liquid water because hydrogen bonds in ice are more "ordered", making ice less dense. If ice sank, all bodies of water would eventually freeze solid, making life on Earth impossible. |
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Adhesion |
The clinging of one substance to another (attraction between different substances - e.g. water and plant cell walls) |
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Cells are compromised of how much water? |
70-95% |
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Calorie (cal) |
The amount of heat it takes to raise the temperature of 1g of water by 1 C (the amount of heat that 1g of water releases when it cools by 1 C) |
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Cohesion |
Hydrogen bonds holding a substance together |
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Buffer |
A substance that minimizes chnges in the concentrations of H+ and OH- in a solution (absorbs or donates H+ ions as needed) Most consist of an acid-base pair that reversibly combines with H+ |
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Heat of vaporization |
The quantitiy of heat a liquid must absorb for 1g of it to be converted from liquid to the gaseous state. |
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Hydration shell |
The sphere of water molecules around each dissolved ion |
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Solvent |
The dissolving agent of a solution |
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Thermal energy |
The kinetic energy associated with the random movement of atoms or molecules. (related to temperature, but not the same). (Passes from warm to cool objects). |
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Surface tension |
A measure of how difficult it is to stretch or break the surface of a liquid |
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What is the biological medum on earth |
Water |
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pH |
The negative logarithm (base 10) of the hydrogen ion concentration (pH = -log [H+]) |
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Heat is absorbed when Heat is released when |
Hydrogen bonds break Hydrogen bonds form |
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Water's specific heat |
1 cal/g x degrees C |
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Heat |
Thermal energy in transfer from one body of matter to another |
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Why does water resist changing its temperature? This phenomenon can be traced to? The benefit of this is? |
Because of its high specific heat Hydrogen bonding Minimizes temperature fluctuations to within limits that permit life. |
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Hydrophilic |
Any substance that hs an affinity for water |
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Hydrogen ion (H+) |
A single proton with a charge of 1+ |
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Acid precipitation |
Rain, snow, or fog with a pH lower than 5.6 |
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Temperature |
A measurement of energy that represents the average kinetic energy of the molecules in a body of matter, regardless of volume. (total thermal energy depends in part on the matter's volume). |
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Colloid |
A stable suspension of fine particles in a liquid |
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Acids add ___ and remove ___ ( ___ combines with ___ forming _____) Bases increase ____ concentration but reduce ____ concentration |
H+ OH- H+ OH- Water OH- H+ |
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What are the four emergent properties of water that contribute to Earth's suitability for life. |
Cohesive behavior Ability to moderate temperature Expansion upon freezing Versatility as a solvent |
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Specific heat |
The amount of heat that must be absorbed or lost for 1g of that substance to change its temperature by 1 C (how well a substance resists changing ts temperature when it absorbs or releases heat). |
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Kinetic Energy |
The energy of motion |
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Aqueous solution |
One in which water is the solvent |
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Occasionally, a hydrogen atom participating in a hydrogen bond between 2 water molecules shifts from one molecule to the other leaving its electron behind. What ions are formed? |
Hydrogen ion (what is actually transferred) (H+) Hydroxide ion (water molecule that lost the proton) (OH-) Hydronium ion (water molecule that gained the proton) (H3O+) 2 H2O <> H3O+ + OH- |
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Base |
A substance that rduces the hydrogen ion (OH-) concentration of a solution. (basic solutions have more OH- than H+) |
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Evaporative Cooling |
As a liquid evaporates, the surface of the liquid that remains behind cools down. ("hottest" molecules, greatest kinetic energy, most likely to leave as gas) |
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Mole (mol) |
Represents an exact number of objects: 6.02 X 10^23 (avogadro's number) |
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Hydroxide ion (OH-) |
Water molecule that lost a proton (hydrogen ion), charge 1- |
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Molecular mass |
To he sum of the masses of all the atoms in a molecule |
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Solution |
A liquid that is a completely homogenous mixture of two or more substances |
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Hydronium ion (H3O+) |
The proton (hydrogen ion) that binds to the other water molecule (non hydroxide ion) |
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pH scale |
Each pH unit represents a tenfold difference in H+ and OH- concentration 0-6: Acid 7: Neutral 8-14: Base |
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Acid |
A substance that increases the hydrogen ion (H+) concentration of a solution. (acid solutions have more H+ than OH-) |
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What are the properties of water |
Cohesion Surface tension Adhesion |
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Kilocalorie (kcal) (1000 cal) |
The quantitiy of heat required to raise the temperature of 1 kg of water by 1 C ("calories" on food package) |
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Water has an equal number of ____ and ____, adding or subtracting can make an ____ or a ______ |
H+ OH- Acid Base |
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Why is water a versile solvent? |
Due to its polarity which allows it to form hydrogen bonds easily. |