Answer. Statement second and third both are correct.
Explanation: When iron(grey) reacts with sulfur(yellow) chemical change takes place in which iron sulfide is formed which black in color.

When we heat copper sulfate-pentahydrate(blue) ,water molecule present in its crystal will get evaporated and it will become an anhydrous copper sulfate which will be white in color.

So, in both the reactions change in color and change in chemical arrangement has taken place.
Answer:
the approximate pressure in the flask after 400. s = 1.2atm
Explanation:
The detailed explanation is shown below
Answer:
Q = -811440 J
Explanation:
Given data:
Mass of oil = 2.76 Kg (2.76× 1000 = 2760 g)
Initial temperature = 191 °C
Final temperature = 23°C
Specific heat capacity of oil = 1.75 J/g.°C
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 23°C - 191 °C
ΔT = -168°C
Q = 2760 g ×1.75 J/g.°C ×-168°C
Q = -811440 J
Negative sign show heat is released.
I believe the correct answer from the choices listed above is the second option. The expression (6.0 x 104) (3.1 x 10-1) is equal to 1.9 x 10^4. We only have two significant figures from the starting expression that is why we rounded of the product from 1.86 to 1.9.
Hi
The volume is 58.1
The moler mass is 10.8
Molar mass details
10.81B (1*10.81)
Hope this helps