Introducere CO

7/30/2019 Introducere CO

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Plants Use Photosynthesis as a Source of Carbohydrates

Green plants and algae have

chlorophyll, a multiringed

compound that contains

magnesium.


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Animals Consume Carbohydrates as a Source of Energy

Carbohydrates, such as the

starch found in this baked

potato, are the main energy

source for most humans


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The formationof four sp3 hybrid orbitals by

combination of an atomic s

orbital with three atomicp

orbitals. Each sp3 hybrid orbital

has two lobes, one of which is

larger than the other. The fourlarge lobes are oriented toward

the corners of a tetrahedron at

angles of 109.5.


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The formation

of sp2 hybrid orbitals by combination

of one s orbital and two

p orbitals. The three hybrids lie

in a plane at angles of 120 to

one another. One unhybridized

p orbital remains, oriented at a

90 angle to the plane of the sp2

orbitals.


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The combinationof one s and onep orbital

gives two sp hybrid orbitals

oriented 180 apart. Two unhybridized

p orbitals remain and

are oriented at 90 angles to the

sp hybrids.


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The s orbital adds to one lobe of

thep orbital and subtracts from the

other lobe of thep orbital.

An s orbital and threep orbitals

hybridize to form four sp3 orbitals.

An sp3 orbital is more

stable than ap orbital, but not asstable as an s orbital.


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(a) The four sp3 orbitals

are

directed toward the

corners of atetrahedron, causing each

bond

angle to be 109.5.

(b) An orbital picture of

methane,

showing the overlap ofeach sp3

orbital of carbon with the s

orbital of a hydrogen. (For

clarity,

the smaller lobes of the

sp3

orbitals are not shown.)


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An hybridized sp2 carbon. The threedegenerate sp2 orbitals lie in a

plane. The unhybridizedp orbital is

perpendicular to the plane. (The

smaller lobes of the sp2 orbitals are

not shown.)


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An sp hybridized carbon. The two

sp orbitals are oriented 180 away

from each other, perpendicular tothe two unhybridizedp orbitals.

(The smaller lobes of the sp orbitals

are not shown.)


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Tetracycline is called a broad-spectrum

antibiotic because it is active against a

wide variety

of bacteria. How many asymmetric carbons

does tetracycline have?


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Coffee, for example, is a familiar source of caffeine. Tea contains both caffeine and

theobromine.


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For a nasty taste, we should mention bittering agents, put into dangerous

household substances like toilet cleaner to stop children eating them by accident.

Notice that this complex organic compound is actually a saltit has positively

charged nitrogen and negatively charged oxygen atoms and this makes it

soluble in water.


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A typical perfume will contain 510%

fragrances in an ethanol/water (about

90:10) mixture.

Chemists produce synthetic flavourings such as smoky bacon and even

chocolate. Meaty flavours come from simple heterocycles such as alkyl

pyrazines (present in coffee as well as roast meat) and furonol, originally found in

pineapples. Compounds such as corylone and maltol give caramel and meaty

flavours. Mixtures of these and other synthetic compounds can be tuned to tastelike many roasted foods from fresh bread to coffee and barbecued meat.


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Ibuprofen (Advil, Motrin, Nuprin): an anti-inflammatory agent

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