Suppose that 145 g of ethanol at 20◦c is mixed

with 235 g of ethanol at 84 ◦c at constant

atmospheric pressure in a thermally insulated

vessel. what is the ∆ssys for the process?

the specific heat capacity for ethanol is 2.42

j/g k.

answer in units of j/k.

∆Ssys = 392.73-179.62 =213.11  J/K.

Explanation:

m_1=145,T_1=20°C

and

m_2=235,  T_2=84 °C

let, specific heat capacity be c(small)=2.42 J/g/K

let,

the constant temperature obtained after mixing is t

so heat absorbed(1st portion of ethanol),

heat  heat lost(2nd portion of ethanol), ,

Now, heat lost= heat gained

,=

=

T=61.25°C

putting values we get

ΔS_1= 392.73 J/ K.

and

ΔS_2= -179.62557  J/K.

∆Ssys = 392.73-179.62 =213.11  J/K.

2b2t

explanation:

2b2t

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.