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16 Cards in this Set
- Front
- Back
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__________ _________ bonds in water result in ______________ bonding |
polar covalent; hydrogen |
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Define polar molecule |
Molecule with unevenly distributed charge |
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Describe hydrogen bonds |
Interactions between slightly positive hydrogen molecule in water with nearby slightly negative molecule. Hydrogen bonds form and break very often, but continually form new bonds with other nearby charged molecules |
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Name the four emergent properties of water that contribute to Earth's suitability as an environment for life |
- cohesive behavior - ability to moderate temperature - expansion upon freezing - versatility as a solvent |
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Describe cohesion |
water molecules sticking together due to hydrogen bonds |
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Describe adhesion |
when one substance clings to another substance; like cohesion, but the two substances are different |
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Define surface tension |
Caused by cohesive properties of a substance (in water, hydrogen bonds); measure of a liquid's elasticity and resistance to have its surface broken |
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What is the difference between thermal energy, temperature, and heat? |
Temperature measures average kinetic energy of molecules in a body of matter, regardless of volume. Total thermal energy instead measures kinetic energy of all molecules in a given volume of matter. Heat is thermal energy transferred from one body to another |
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Define specific heat |
amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1 degree Celsius |
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Why does water have a high specific heat? |
Hydrogen bonds. Heat must be absorbed to break those bonds, meaning the heat first goes toward breaking the hydrogen bonds before it goes to increasing the kinetic energy of the water molecules themselves |
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What happens during evaporative cooling? |
The molecules with the greatest kinetic energy are the first to escape to the gaseous state, leaving behind molecules with lesser kinetic energy that decrease the overall average kinetic energy, which we interpret as temperature |
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Define aqueous solution |
Solution in which water is the solvent |
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Define hydration shell |
The sphere of water molecules around each dissolved ion, caused by the polarity of water molecules |
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Explain the concept of liquid water as a solvent in your blood |
Blood is 55% plasma, 92% of which is water. The water forms hydrogen bonds with the solutes, allowing everything from proteins to electrolytes to be carried in the liquid portion of the blood |
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Describe what acids do when they dissolve in water |
Increases the concentration of hydrogen ions, thereby increasing the concentration of hydronium ions |
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Describe what bases do when they dissolve in water |
Decrease the hydrogen ion concentration, either by directly taking hydrogen ions, or by dissociation to form hydroxide ions and then combining with free hydrogen ions to form water |
