Answer:
Explanation:
<em>0.5 i go to k12 i jus took the test</em>
 
        
                    
             
        
        
        
Explanation:
13 are the number of atoms
 
        
             
        
        
        
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:
Extensive Properties
Explanation:
A physical property that will change if the amount of matter changes. Change in which the matter's physical appearance is altered, but composition remains unchanged. Solid is distinguished by a fixed structure. Its shape and volume do not change.