Be-beryllium have 2 electrons and it is in the 2 nd period
We are given with the mass of Arsine (
The mass of arsine is 15g
there is a relation between moles, mass and molar mass of any compound which is
The molar mass of Arsine = atomic mass of As + 3X atomic mass of H
the molar mass of Arsine = 74.92 + 3X 1 = 77.92 g/mol
Let us calculate the moles as
Answer: Friction is a force that resists relative motion between two surfaces in contact. Depending on the application, friction may be desirable or undesirable.
Answer:
the ph of an aqueous solution of sulphuric acid which is 5*10^5 mol in concentration is basic in nature
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