Carboxylic acids: considered as weak acids due to they ionize in solution to give -COO⁻ and H⁺, they are abundant in nature, they can form intermolecular hydrogen bonds so they exist as dimers (remember that alcohols also can form hydrogen bonds).
- Acids have higher boiling and melting points than corresponding molar mass compounds due to the formation of hydrogen bond
- Aromatic carboxylic acids are solids in nature at room temperature
Most of the elements important in biology need eight electrons in their outermost shell in order to be stable, and this rule of thumb is known as the octet rule. Some atoms can be stable with an octet even though their valence shell is the 3n shell, which can hold up to 18 electrons.
Answer:
The process of dissolving can be endothermic (temperature goes down) or exothermic (temperature goes up).
When water dissolves a substance, the water molecules attract and “bond” to the particles (molecules or ions) of the substance causing the particles to separate from each other.
The “bond” that a water molecule makes is not a covalent or ionic bond. It is a strong attraction caused by water’s polarity.
It takes energy to break the bonds between the molecules or ions of the solute.
Energy is released when water molecules bond to the solute molecules or ions.
If it takes more energy to separate the particles of the solute than is released when the water molecules bond to the particles, then the temperature goes down (endothermic).
If it takes less energy to separate the particles of the solute than is released when the water molecules bond to the particles, then the temperature goes up (exothermic).
Explanation:
If you were to take water (like many other materials) and break it up into almost the smallest things you could, you’d get molecules. If the molecules are stuck together really tightly in a regular pattern, then they’re called a solid. The solid form of water is ice. This actually makes a lot of sense, because it certainly does seem like all the little parts of a solid (like ice) are stuck together very tightly.
When you heat something up, it makes the molecules move faster. If you heat up a typical solid, it melts and becomes a liquid. In a liquid (like water), the molecules are still stuck together, but they can move around some. What actually happens is that the molecules are still sort of sticking together, but they’re constantly breaking apart and sticking to different molecules. This also makes sense when you think about water. Water sort of sticks together, but it breaks apart /really/ easily.
If you heat a liquid like water up even more (like if you put it in a pot on the stove), then the molecules will move around so fast that they can’t even hold on to each other at all. When this happens, all of the molecules go flying apart and become a gas (like when you boil water to make steam). The process of gas molecules leaving the liquid to go into the gas is called "evaporation." The opposite process is called "condensation."
<span>Hope this answers your question!</span>
You must use 134 g O₂ to produce 118 g H₂O.
M_r: 32.00 18.02
2H₂ + O₂ ⟶ 2H₂O
Moles of H₂O = 150.9 g H₂O × (1 mol H₂O/18.02 g H₂O) = 8.374 mol H₂O
Moles of O₂ = 8.374 mol H₂O × (1 mol O₂/2 mol H₂O) = 4.187 mol O₂
Mass of O₂ = 4.1877 mol O₂ × (32.00 g O₂/1 mol O₂) = 134 g O₂
