Chemistry & Energy - Water Flashcards
(15 cards)
Water is what kind of bond?
Covalent.
Is water polar/non-polar?
Polar.
The H’s are slightly positive-charged,
the O is slightly negative-charged.
The polarity of water molecules causes water molecules to…?
Stick together. The + H’s stick to the - O’s by a hydrogen bond.
Cohesion is the…?
Attraction between two things.
Water has the highest cohesion of…?
…any non-metallic liquid.
Adhesion is…?
Attraction between two diff substances.
Capillary action def:
Ability of a liquid to flow in narrow spaces without the affect of external forces, like gravity.
Water is a solvent or solute? Explain.
Solvent.
There are more substances that can be dissolved in water, than in any other liquid on Earth.
Two Hydrophilic molecule examples? Why are they -philic? What’s a practical explanation of what’s happening
Sugar and Salt.
Because they’re polar, and polarity is stronger (in bonding) than the cohesive forces of water.
Practically, when salt or sugar is in water, it’s polarity is strong enough that it breaks the hydrogen bonds of the water. Instead of the salt or sugar bonding to the water, the water bonds to itself around the salt or sugar.
What happens when there is a molecule that can’t break/overcome the strong, cohesive forces of water and get into the water?
That’s what we call “Hydrophobic” substances.
Hydrophobic molecule characteristics:
1) they’re non-polar, they lack charged poles;
2) they’re unable to dissolve in water because they’re essentially being pushed out of water by water’s cohesive forces.
Ice density. Explain why when frozen it’s less dense than liquid water.
At 0° C:
- water molecules start to solidify,
- hydrogen bonds between them start to form crystalline structures that space water molecules apart more evenly,
- when the molecules are spaced apart more evenly, it causes density to be much lower.
Water has a very high…?
…Heat capacity.
The oceans do what for the climates near them?
They regulate the climates, by essentially acting like heat sinks.
Explain sweat in terms of heat capacity.
When a body gets hot, it excites the water molecules on my skin to the point where their hydrogen bonds are broken and they evaporate away, taking the heat with them, leaving me cooler.
