The true answer is: It's conserved because the total number of H atoms on each side is 12.
the first two answer is wrong because it's conserved not as mentioned, It's not conserved.
and the last one also wrong because the total number of O atoms are equal at the two sides but not equal 2.
In order to make the dissolution of the solid compound in water to occur at a faster rate, Samuel could do the following:
1. Break down the solid into tiny particles: breaking down the solid into tiny particles increases the surface area of the solid and thus increase the quantity of the substance that comes in contact with the solvent per time, this leads to a faster dissolution of the solid.
2. Stir the liquid with iron rod: Samuel can increase the dissolution rate of the substance by stirring it continuously with iron rod.
3. Increasing the temperature:Samuel could also increase the rate of dissolution of the substance by increasing the temperature of the water.
C + H2O -> H2 + CO
n(C) = 15.9/12 = 1.325 (mol)
=> n(H2) = 1.325 mol
We have:
PV = nRT
=> V = (nRT)/P
(R = 22.4/273 = 0.082)
V = (1.325 x 0.082 x 360)/1 = 39.114 (L)
I think the answer is B. static charge. I hope this helps! :)