The atomic mass of K is 39
from Avogadro's law
39g of K contains 6.02x10^23 atoms
therefore if
39=6.02x19^23
X=5.11×10^22
making X the subject of the formula
X= (5.11×10^22×39)÷6.02×10^23
X= 33g
<span>To solve this exercise you need to know that to create CO₂ with C₂H₂ is necessary to have oxygen. So, the following balanced equation represents the reaction:
2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(g)
Notice that 2 moles of C₂H₂ form 4 moles of </span><span>CO₂, so if </span>3.3 moles of C₂H₂ react, how many moles of CO2 would be produced?
2 moles <span>of C₂H₂ -------</span>4 moles of <span>CO₂
3.3 </span><span>moles <span>of C₂H₂--------x moles of CO₂
x=6.6 </span></span><span>moles of CO₂ produced.</span>
The number of moles in monochloro pentaborane (9) 
is 0.37056.
We know that ,
Number of moles = Given mass/ Molar mass
Given mass of monochloro pentaborane (9) is 20.1 g
The molar mass of monochloro pentaborane (9) is
= 
= 
= 54.241
Thus number of moles = 20.1/54.241
= 0.37056
To know more about mole concept
brainly.com/question/20483253
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