This reaction is called silioconic
Molecular mass of H2O is: 16+2*1=18
so moles of 40g of H2O is: 40/18=2.22
Complete Question
The complete question is shown on the first uploaded image
Answer:
The concentration of
that should used originally is 
Explanation:
From the question we are told that
The necessary elementary step is

The time taken for sixth of 0.5 M of reactant to react 
The time available is 
The desired concentration to remain
Let Z be the reactant , Y be the first product and X the second product
Generally the elementary rate law is mathematically as

Where k is the rate constant ,
is the concentration of Z
From the elementary rate law we see that the reaction is second order (This because the concentration of the reactant is raised to power 2 )
For second order reaction

Where
is the initial concentration of Z which a value of 
From the question we are told that it take 9 hours for the concentration of the reactant to become


So


=> 
For 





Answer:
Number of proton is 11
Number of neutrons is 12
Number of electrons is 10
Explanation:
For a neutral Na, Sodium atom:
The mass number P+N = 23
Atomic number(E or P) = 11
A charged Na atom that has lost an electron is positively charged and so:
Number of proton = 11 (Still the same)
Number of neutrons = 12
Number of electrons = 11-1=10 (the atom has lost an electron)
If an atom loses electron, it becomes positively charged ie P>E
Molar mass of Calcium ( Ca ) = 40.078 g/mol
Number of moles in 9.8 grams :
1 mole Ca -----------> 40.078 g
mole Ca -------------> 9.8 g
moles Ca = 9.8 / 40.078
moles Ca = 0.2445 moles
number of molecules:
1 mole ----------------> 6.02x10²³ molecules
0.2445 moles --------> ?
= 0.2445 * 6.02x10²³
= 1.47x10²³ molecules
hope this helps!.