Answer: The total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.
Explanation:
Given: Mass = 46 g
Initial temperature = 
Final temperature = 
Specific heat capacity of ice = 2.05 
Formula used to calculate the energy is as follows.

where,
q = heat energy
m = mass
C = specific heat capacity
= initial temperature
= final temperature
Substitute the values into above formula as follows.

Thus, we can conclude that the total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.
According to the second order formula:
1/[At] = K t + 1/[Ao]
and when we have the K constant =0.0265 & we have t = 180 min & we have the initial concentration of A = 4.25 so by substitution:
1/[At] = 0.0265 X 180min + 1/4.25
1/[At] = 5
∴[At] = 1/5 = 0.2 m
Answer:
a) 210.3 g/mol
b) 210.2 g/mol
c) 384.5 g/mol
Explanation:
First step we will calculate the molar masses of ; carbon atom, hydrogen atom and oxygen atom in each .
<u> Molar mass of dibenzyl ketone</u>
Molar mass of dibenzyl ketone = ∑ molar masses of atoms in dibenzyl ketone
= carbon( 15 ) = 15 ( 12.0107 ) + oxygen ( 14 ) = 1 ( 15.999 ) + hydrogen(14) =14(1.00784)
= 210.26926 ≈ 210.3 g/mol
<u> Molar mass of benzil</u>
Molar mass of Benzil = ∑ molar masses of atoms in Benzil
= carbon( 14) = 14(12.0107) + oxygen(2) = 2 ( 15.999) + hydrogen(10) =10(1.00784)
= 210.2262 ≈ 210.2 g/mol
<u>Molar mass of 2,3,4,5-tetraphenylcyclopentadienone</u>
Molar mass = ∑ molar masses of atoms
= carbon ( 29) = 29(12.0107) + oxygen (1) = 1( 15.999 ) + hydrogen(20) = 20(1.00784 )
≈ 384.5 g/mol