Answer is: <span>molecular formula of retinol is C</span>₂₀H₃₀O.
n(C) = 83,84 g ÷ 12 g/mol.
n(C) = 6,99 mol.
n(H) = 10,58 ÷ 1,008 g/mol.
n(H) = 10,5 mol.
n(O) = 5,58 g ÷ 16 g/mol.
n(O) = 0,348 mol.
n(C) : n(H) : n(O) = 6,99 mol : 10,5 mol : 0,348 mol /:0,348.
n(C) : n(H) : n(O) = 20 mol : 30,1 mol : 1.
The least reactive out of those options is helium. Alkali metals are very reactive while noble gases are stable, and helium is a noble gas.
When energy is needed in order for the reaction to happen, then that reaction is known as endotermic. When the reaction has as a result energy then it is exotermic. An example of an endotermic reaction would be photosynthesis, for an exotermic: combustion.
Answer:
2621.75 j heat is required to increase the temperature 25.5°C to 46°C.
Explanation:
Given data:
Mass of sample = 142.1 g
Initial temperature = 25.5°C
Final temperature = 46°C
Specific heat capacity of Al = 0.90 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 = 46°C - 25.5°C
ΔT = 20.5°C
Q = 142.1 × 0.90 J/g.°C × 20.5°C
Q = 2621.75 j
Thus, 2621.75 j heat is required to increase the temperature 25.5°C to 46°C.
