Answer:
The procedure you will use in this exercise exploits the difference in acidity and solubility just described.
(a) you will dissolve your unknown in ethyl acetate (an organic solvent). All of the possible compounds are soluble in ethyl acetate.
(b) you will extract with sodium bicarbonate to remove any carboxylic acid that is present.
(c) you will extract with sodium hydroxide to remove any phenol that is present.
(d) you will acidify both of the resulting aqueous solutions to cause any compounds that were extracted to precipitate.
Answer:
CCl4- tetrahedral bond angle 109°
PF3 - trigonal pyramidal bond angles less than 109°
OF2- Bent with bond angle much less than 109°
I3 - linear with bond angles = 180°
A molecule with two double bonds and no lone pairs - linear molecule with bond angle =180°
Explanation:
Valence shell electron-pair repulsion theory (VSEPR theory) helps us to predict the molecular shape, including bond angles around a central atom, of a molecule by examination of the number of bonds and lone electron pairs in its Lewis structure. The VSEPR model assumes that electron pairs in the valence shell of a central atom will adopt an arrangement which tends to minimize repulsions between these electron pairs by maximizing the distance between them. The electrons in the valence shell of a central atom are either bonding pairs of electrons, located primarily between bonded atoms, or lone pairs. The electrostatic repulsion of these electrons is reduced when the various regions of high electron density assume positions as far apart from each other as possible.
Lone pairs and multiple bonds are known to cause more repulsion than single bonds and bond pairs. Hence the presence of lone pairs or multiple bonds tend to distort the molecular geometry geometry away from that predicted on the basis of VSEPR theory. For instance CCl4 is tetrahedral with no lone pair and four regions of electron density around the central atom. This is the expected geometry. However OF2 also has four regions of electron density but has a bent structure. The molecule has four regions of electron density but two of them are lone pairs causing more repulsion. Hence the observed bond angle is less than 109°.
Answer:
A Walk in the City
Make a list of the number of cars, jeeps, tricycle, and even trucks you've seen on your way to school. On a Decision Making Chart, answer the question, "Does the volume of traffic affect the air quality in my local community?" Write your reasons for saying YES on the Reasons for column, and the reasons for saying NO on the Reasons Against column. At the bottom of a chart, make a position by writing your decision on the same question.
Decision Making Chart
[question]
[reason for]
[reason against]
[my decision]
A chemical formula shows the kinds and numbers of <u>atoms</u> in the smallest representative unit of a substance.
<u>Explanation:</u>
In chemistry, a formula unit is the empirical formula of "ionic or covalent network solid compound" that is used as an independent entity for "stoichiometric calculations". This formula is a representation of a molecule that uses chemical symbols.
The unit is the lowest whole number ratio of ions represented in an ionic compound. It gives the numbers of atoms representing the "smallest representative" unit of a substance. The number of atoms also tells us about the chemical and physical properties of the compound formed.
Answer:
2:a-heterogenous
b-homogenous
c-heterogenous
d-heterogenous with water
3:Filtration is used to separate insoluble particles from a solution
Distillation is used to separate liquids with close but different boiling points e.g water and ethanol
Explanation:
2: homogenous mixtures form a uniform layer meaning that a mixture containing more than one layer is heterogenous
