Answer:
2.04 x 10²⁴ molecules
Explanation:
Given parameters:
Mass of Be(OH)₂ = 145.5g
To calculate the number of molecules in this mass of Be(OH)₂ we follow the following steps:
>> Calculate the number of moles first using the formula below:
Number of moles = mass/molarmass
Since we have been given the mass, let us derive the molar mass of Be(OH)₂
Atomic mass of Be = 9g
O = 16g
H = 1g
Molar Mass = 9 + 2(16 + 1)
= 9 + 34
= 43g/mol
Number of moles = 145.5/43 = 3.38mol
>>> We know that a mole is the amount of substance that contains Avogadro’s number of particles. The particles can be atoms, molecules, particles etc. Therefore we use the expression below to determine the number of molecules in 3.38mol of Be(OH)₂:
Number of
molecules= number of moles x 6.02 x 10²³
Number of molecules= 3.38 x 6.02 x 10²³
= 20.37 x 10²³ molecules
= 2.04 x 10²⁴ molecules
Answer:
D is the answer may be. I'm not sure.
Answer:
Region B, because the pressure inside the cylinder is equal to the vapor pressure of water at 80∘C when both liquid and gas phases are present.
Explanation:
As expansion occurs, liquid water evaporates reversibly, holding the pressure constant at the equilibrium vapor pressure of water at 80∘C(0.47atm) 80∘C (0.47 atm). When all of the liquid has evaporated, the pressure drops and follows the ideal gas law.
Answer:
molar mass (molar weight)
Explanation:
