100 POINTS How many kilojoules of heat are required to vaporize 30.0 grams of ethanol (C, H,OH) if the boiling point of ethanol is 78.5C?
C, H,OH + 30, +43.5 kJ → 2 CO2 + 3 H20

H

3

CCH

2

OH(

l

)

+

Δ

→

H

3

CCH

2

OH

(

g

)

You have a mass of

50.0

⋅

g

EtOH

, that is assumed to be at

78.3

∘

C

, and the enthalpy of vaporization is calculated by the product:

Δ

H

∘

vaporization

=

50.0

⋅

g

46.07

⋅

g

⋅

m

o

l

−

1

×

38.6

⋅

k

J

⋅

m

o

l

−

1

=

=

?

?

⋅

k

J

.

question: ray weighs 100 kilograms, his wrestling partner, bobby, weighs 50 kilograms. if ray moves at 4 m s , how fast will bobby have to run at him to apply an equal amount of kinetic energy?

answer: 8 m/s he needs to run twice as fast to keep up so he has some work to do

explanation:   if the mass has units of kilograms and the velocity of meters per second, the kinetic energy has units of kilograms-meters squared per second squared.

question answered by

(jacemorris04)

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.