Answer:
A. When two aqueous solutions are mixed, a precipitate is formed.
Explanation:
The precipitate (a solid substance that falls from the liquid) is the result of a chemical reaction taking place between the liquids.
The other three answer choices are indicative of physical changes (temperature change, phase change, color change).
Answer:
You may be referring to the gas that makes up 21% of the earth's atmosphere, which is oxygen.
Explanation:
According to NASA, the gases in Earth's atmosphere include:
Nitrogen — 78 percent
Oxygen — 21 percent
Argon — 0.93 percent
Carbon dioxide — 0.04 percent
(Trace amounts of neon, helium, methane, krypton and hydrogen, as well as water vapor)
In the first distillation this week, Hexane from the original solvent makes a larger contribution to the vapor pressure of the mixture.
In between hexane and toluene, the hexane will have more vapor pressure contribution in the solution. The boiling point of hexane is much lower than toluene. Therefore, it will evaporate easily at low temperatures and start exerting pressure on the solution.
Hence between hexane and toluene, because of more vapor pressure of hexane and lower boiling point, it will easily evaporate and exerts pressure.
Therefore, from the original solvent, hexane makes a larger contribution to the vapor pressure of the mixture.
To learn more about vapor pressure and hexane, visit: brainly.com/question/28206662
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Ionic bonds usually occur between metal and nonmetal ions. For example, sodium (Na), a metal, and chloride (Cl), a nonmetal, form an ionic bond to make NaCl. In a covalent bond, the atoms bond by sharing electrons. Covalent bonds usually occur between nonmetals.
Explanation:
The nitrate anion is a univalent (-1 charge) polyatomic ion composed of a single nitrogen atom ionically bound to three oxygen atoms (Symbol: NO3) for a total formula weight of 62.05. Lead Nitrate is generally immediately available in most volumes.
