Mixture? | Solution?

[kingwinner]

1) Which of the following is not an element

a) Ozone :friday: Water c) Krypton d) Lead

I am not sure if the answer is (a) or (:eek:, does anyone have any idea?

 

2) The earth's atmosphere is an example of a

a) solution :friday: mixture c) both (a) and (:friday:

The standard answer in my text book is ©, but I don't understand why...I picked (:hihi:, why is the atmosphere also a solution?

 

3) Why is an alloy a solid solution? Does that mean the solvent is solid? Why is it not a compound?

 

Can somebody explain? Thanks!

[Tormod]

1) Which of the following is not an element

a) Ozone :friday: Water c) Krypton d) Lead

I am not sure if the answer is (a) or (:friday:, does anyone have any idea?

 

Water is a molecule that consists of more than one element (two hydrogen atoms and one oxygen atom). Ozone is a molecule consisting of three oxygen atoms. Thus ozone is an element whereas water is not.

[Jay-qu]

Tormod beat me to the only answer I was sure of, but I will try...

 

2. I think your book is meaning that it is a mixture because elemental gases (H, O, N and others) are all mixed together, but also small amounts of compounds of these (H2O, NO2)

 

3. "solid solution

n.

A homogeneous crystalline structure in which one or more types of atoms or molecules may be partly substituted for the original atoms and molecules without changing the structure."

 

so in an alloy when you have more than one type of metal its atoms will be substituted into the crystalline lattice and because metallic bonding occurs I guess it cant be a mixture so its called a solid solution. That is the first time I have heard of them before, interesting... :friday:

[kingwinner]

1) So the answer is (:hihi:, but ozone is an element? It has covalent bonds though... :friday:

 

2) A solution is an example of a homogeneous mixture, so if the atmosphere satisfies (a)-solution, it must satisfy (:friday:-mixture too, and the answer is ©-both (a) and (:friday:

 

The thing is I don't get how the atmosphere would be a solution, or a homogeneous mixture...

 

3) By solid solution, does it mean the solvent and the solute both are solid? So what would you call if a liquid in dissolved in a solid, is this still a solid solution? What if CO2(g) is dissolved in H2O(l)? Liquid solution?

[Jay-qu]

1) So the answer is (:eek:, but ozone is an element? It has covalent bonds though... :friday:

 

2) A solution is an example of a homogeneous mixture, so if the atmosphere satisfies (a)-solution, it must satisfy (:friday:-mixture too, and the answer is ©-both (a) and (:friday:

 

The thing is I don't get how the atmosphere would be a solution, or a homogeneous mixture...

 

3) By solid solution, does it mean the solvent and the solute both are solid? So what would you call if a liquid in dissolved in a solid, is this still a solid solution? What if CO2(g) is dissolved in H2O(l)? Liquid solution?

 

1. Like Tormod said Ozone is O3 it has only oxygen - it is an element.

 

3. See the definition I gave above? there is no traditional solvent and solute when it is solid. If the liquid replaces some atoms in the structure of the solid without changing the structure then it would be a solid solution

[UncleAl]

Ozone is an allotrope of oxygen just as graphite, diamond, fullerenes, closed-end nanotubes, adn presumably polycarbyne are allotropes of carbon. A compound requires two or more elements. None of the carbon examples are organic compounds.

 

The atmosphere is a miscible solution of gases mixed with immiscible stuff like clouds and dust.

 

Alloys are solid solutions because they have phase diagrams rather than fixed fixed stoichiometries. Compounds of metals are intermetallics,

 

http://en.wikipedia.org/wiki/Purple_plague_(intermetallic)

http://en.wikipedia.org/wiki/Intermetallic

http://www.aeat.co.uk/mcpa/areas/software/database/mgdata.htm

[kingwinner]

Ozone is an allotrope of oxygen just as graphite, diamond, fullerenes, closed-end nanotubes, adn presumably polycarbyne are allotropes of carbon. A compound requires two or more elements. None of the carbon examples are organic compounds.

 

The atmosphere is a miscible solution of gases mixed with immiscible stuff like clouds and dust.

 

Alloys are solid solutions because they have phase diagrams rather than fixed fixed stoichiometries. Compounds of metals are intermetallics,

 

http://en.wikipedia.org/wiki/Purple_plague_(intermetallic)

http://en.wikipedia.org/wiki/Intermetallic

http://www.aeat.co.uk/mcpa/areas/software/database/mgdata.htm

2) How does it differ if gases mix homogeneously or heterogenerously? What does it actually mean by N2 and O2 mixing homogeneously (i.e. solution)! For what reason is the earth's atmosphere being considered as a solution/homogeneous mixture?

[UncleAl]

Uncle Al can explain it to you. Uncle Al cannot understand it for you.

[HydrogenBond]

UncleAl summarized the differences rather well. Homogeneous means all the same. The gases within air will distribute themselves uniformly. If one took a sample anywhere in the volume it will be the same proportions. The same can be said for solutions; they also are uniform throughout. One can take a sample of NaCl solution at steady state and it will be the same throughout.

 

If one was to dump some freon gas into a box of air and immediately take a sample, the freon will sink to the bottom and the air will float on top. This would be an example of a heterogeneous mixture. Another example would be lighting a candle in a closed room. The oxygen levels will drop near the candle while the CO2 concentrations would be higher near the candle. If would remain heterogeneous until the candle goes out and the gases become homogeneous.

[kingwinner]

UncleAl summarized the differences rather well. Homogeneous means all the same. The gases within air will distribute themselves uniformly. If one took a sample anywhere in the volume it will be the same proportions. The same can be said for solutions; they also are uniform throughout. One can take a sample of NaCl solution at steady state and it will be the same throughout.

 

If one was to dump some freon gas into a box of air and immediately take a sample, the freon will sink to the bottom and the air will float on top. This would be an example of a heterogeneous mixture. Another example would be lighting a candle in a closed room. The oxygen levels will drop near the candle while the CO2 concentrations would be higher near the candle. If would remain heterogeneous until the candle goes out and the gases become homogeneous.

But in the atmosphere, there are some regions with higher CO2 level, while some others with higher O2 level, so the air components aren't uniformly dispersed. Having said that, why is the atmosphere still being considered as a SOLUTION?

[HydrogenBond]

The atmosphere is not a closed system. For example, the evaporation of surface water will eventually result in the water concentrating as clouds due to hydrogen bonding. If we had a closed system, using the gases of the atmpsphere, they would form a solution where each gas molecule would maximize entropy and minimize enthalpy. The water may still cluster to lower enthalpy. but would do so uniformly throughout.