Mass = PROTONS + neutrons. So, 19 +20 = 39.
(Don't confuse yourself between electrons and protons when they are equal because it could be an ion)
Given :
a.
b.
c.
d.
.
To Find :
Find the most likely vale of x for each one .
Solution :
a .
Because boron have valency of 3 .
So , x = 3 .
b . 
Valency of carbon is 4 .
x = 4 .
c . 
Valency of nitrogen is 3 .
Therefore , x = 3 .
d . 
Now ,we know valency of carbon is 4 and hydrogen is 1 .
Also , two hydrogen are already there .
So , only 2 electrons left to share .
Since , chlorine have valency of 1 .
Therefore , only 2 electrons of chlorine can connect .
x = 2 .
Hence , this is the required solution .
Answer:
C the mass of each product formed
Explanation:
To the determine the limiting reactant, it is essential that we have the balanced equation of the reaction from which we can calculate the stochiometry mole ratio of the reactant. After this, we need to calculate the molar mass of the reactants, using the mole from the balanced equation we can calculate each mass of each reactant needed. Finally we need the mass of each reactant using proportion we can calculate the amount needed for the reaction from the masses of the reactant by comparing the mass given against the mass calculated from the balanced equation. After this, the mass that is exhausted or that is finished will be the limiting reactant which is the reactant that finished and caused the reaction to stop.
H2-element
HCl-compound
Na-element
Al2O3-compound
H2O-compound