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20 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is a polar molecule?
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A molecule in which opposite ends of the molecule have opposite charges.
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Water - H2O
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What is kinetic energy?
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It is the energy of motion. The faster the molecule moves, the greater its kinetic energy.
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What is heat?
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It is the measure of the total amount of kinetic energy due to molecular motion.
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What is temperature?
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It measures the intensity of heat due to the average kinetic energy of the molecules.
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What is a calorie?
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It is the amount of heat it takes to raise the temperature of 1g of water by 1C.
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What is a kilocalorie?
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A kilocalorie, 1000 calories, is the amount of heat required to to raise the temperature of 1 kilogram of water by 1 degree Celsius.
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Calories on packages are actually kilocalories.
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What is the specific heat of a substance?
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The amount of heat that must be absorbed or lost for 1gram of that substance to change its temperature by 1 degree Celsius.
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What is vaporization?
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It is the transformation from a liquid to a gas.
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AKA evaporation
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Is water more or less dense as a solid than as a liquid?
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It is less dense as ice can float on water.
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What is a solution?
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A completely homogeneous mixture of two or more substances. It is made up of a solvent (the dissolving agent) and a solute (the substance that gets dissolved).
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What is an aqueous solution?
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One in which water is the solvent.
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What is a hydration shell?
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The sphere of water molecules around each dissolved ion.
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Define hydrophilic.
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Any substance, ionic or polar, that has an affinity for water (tend to dissolve).
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NaCl (salt is an example)
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Define hydrophobic.
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Any substance, nonionic and nonpolar, that does not have an affinity for water (tends to not mix).
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vegetable oil is an example.
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What is molecular mass?
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It is the sum of all masses of each atom in a molecule.
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Define molarity.
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It is the number of moles of solute per liter of solution.
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Explain hydrogen ion.
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This is what happens when a hydrogen atom between two water molecules shifts from one molecule to the other. It leaves its electron behind resulting in a 1+ charge.
The water molecule that lost a proton is now a hydroxide ion (OH-) and the other is a hydronium ion (H3O+) |
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Define acid.
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It is a substance that increases the hydrogen ion concentration of a solution.
Solutions with higher concentration of H+ than OH- are known as acidic solutions. |
HCl---->H+ +Cl-
hydrochloric acid |
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Define base.
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Is is a substance that reduces the hydrogen ion concentration of a solution.
Solutions with higher concentration of OH- than H+ are known as basic solutions. |
NH4+---->NH3+H4
Ammonia |
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Define buffers.
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Substances that minimize changes in the concentrations of H+ and OH- in a solution.
Accepts hydrogen ions from the solution when they are in excess and donates hydrogen ions to the solution when they have been depleted. |
help to maintain the pH of human blood level to close to 7.4
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