The answer u are looking for is b
<u>a) Answer: </u>
<em>Number of molecules in 1 mole</em>
<u>Explanation:</u>
a) Whether we take any of the substance among all three of the given substances they will have the same number of molecules in 1 mole of the substance is considered and the value for this will be 
<u>b) Answer: </u>
<em>In the given question </em><em>mass of the substance</em><em> which is </em><em>greatest</em><em> is asked for </em><em>one mole</em><em> and we also know that </em><em>mass of one mole is given by molar mass. </em>
<u>Explanation:</u>
b) It is known that
is the molar mass for oxygen which is greater than that of hydrogen while fluorine has a molar mass of
which on comparison shows that, it is the highest amongst all three.
Solutions are said to be C. homogeneous mixtures, composed of two or more substances. It is usually liquid, however it may be solid or gas.
The final temperature : 78.925°C
<h3>Further explanation </h3>
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C
∆T = temperature difference, ° C / K
Energy releases = 130 kcal = 130 x 4.18 kJ=543.4 kJ
The final temperature :

Final temperature :
ΔT=final-initial
51.925°c=final-27°c
final = 51.925+27=78.925°C
5.367 ml of the concentrated acid must be added to obtain a total volume of 100 ml of the dilute solution.
Dilution is defined as the process in which the concentration of a sample is decreased by adding more solvent. The dilution formula is given below.
C₁V₁ = C₂V₂
where C₁ = initial concentration of sample = 3.00 m
V₁ = initial volume of sample
C₂ = final concentration after dilution = 0.161 m
V₂ = total final volume after dilution = 100 ml
Plug in the values to the formula and solve for the volume of the concentrated acid that must be added.
C₁V₁ = C₂V₂
3.00 m (V₁) = 0.161 m (100 ml)
V₁ = 5.367 ml
Learn more about dilution here: brainly.com/question/1615979
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