A few questions.
1. What is the difference btwn crystalization and precipitation?
2. What will happen if you choose a solvent whose boiling point is higher than the melting point of the compound to be crystalized?
3. Generally describe how to predict solubility.
1. just checking my thinking on this. Crystalization is the actual process of forming crystals while precipitation is actually getting a solid out of solution right?
2. No clue ..
3. To predict solubility:(my thinking)
a) determine if the molecule to be dissolved is polar or nonpolar since like dissolves like.
b)hydrocarbons = nonpolar
1. the more carbons on a compound the more hydrocarbonlike it is.
c)If it has a electronegative atom in the compound such as N and O then it is polar.
1. If the atom is a halogen thus having high electronegativity then it is polar but not alot since the halogen doesn't have a great effect on the organic compound.
2. If the molecule has a few carbons compared with alot of carbons and also has a electronegative atom in the compound then the one with fewer is more soluble in water b/c water is polar and the fewer carbons it has would make it more polar and having more carbons would make it more hydrocarbon like. (less polar)
d) Compounds that belong to the same "family" are soluble with each other but only if their size is similar. If there is a great size difference then that doesn't work.
e)dipole dipole forces of attraction btwn the hydrogens of one molecule and the electronegative atom in another molecule. (F,O,N)
Is this correct?
I'm not sure how to make my explanation for #3 in general terms (shorter abreviated form)
Thanks =)
Your explaination for the number 3 is sufficient.
Number one, they are the same, except crystallization is very slow precipation of a solute that has strong bonds in the sold form.
Number two. Solvents do not melt solutes: solutes dissolve because of forces between the solute and solvent. Think about this with sugar dissolving in water.
For #2 nothing would happen then right?
Nothing. Think again about sugar, the mp of sugar is well above the bp of water.
But the question asked what would happen if the solvent's boiling point was higher than the melting point not if the melting point was higher than the boiling point Bob.
ex.
Since the solvent is the water and the solute is the sugar. (Q: the solvent's boiling point higher than the melting point of the solute)
1. Your understanding of crystallization and precipitation is correct. Crystallization is the process of forming crystals from a solution, where the molecules in the solution come together in an organized pattern to form a solid crystal. Precipitation, on the other hand, refers to the formation of a solid from a solution when the solute concentration exceeds its solubility limit and a solid phase separates out.
2. If you choose a solvent whose boiling point is higher than the melting point of the compound to be crystallized, the compound may not dissolve completely in the solvent because the compound's melting point will likely be lower than the boiling point of the solvent. This can result in incomplete crystallization or the formation of impure crystals. It's generally recommended to choose a solvent with a boiling point lower than the melting point of the compound to ensure efficient and complete crystallization.
3. To predict solubility, you can consider several factors:
a) Polarity: Determine if the molecule to be dissolved is polar or nonpolar. Generally, polar solutes will dissolve in polar solvents, and nonpolar solutes will dissolve in nonpolar solvents. Like dissolves like.
b) Hydrocarbons and size: Hydrocarbons are generally nonpolar. The more carbons a compound has, the more hydrocarbon-like it is and the less soluble it tends to be in polar solvents. Additionally, compounds belonging to the same "family" (having similar functional groups) are generally more soluble with each other, but only if their sizes are similar. A significant size difference can affect solubility.
c) Presence of electronegative atoms: If a molecule contains electronegative atoms such as nitrogen (N) or oxygen (O), it tends to be polar. If the molecule has a halogen, it can also be polar but to a lesser extent. These polar molecules are more likely to dissolve in polar solvents.
d) Intermolecular forces: Consider the presence of dipole-dipole forces of attraction between the hydrogens of one molecule and the electronegative atom in another molecule (F, O, N). These forces can enhance solubility in certain solvents.
It's important to note that solubility is a complex phenomenon influenced by multiple factors, and these guidelines provide a general understanding. Real-life solubility can also be influenced by temperature, pressure, and other specific properties of the solute and solvent.
I hope this explanation helps clarify your understanding! Let me know if you have any further questions.