The answer is; C
Conservation of matter in a reaction means that the mass of matter in the products is equal to the mass of the reactants. Energy/matter cannot be created or destroyed but converted from one form to another.
An expanding balloon with the increased evolution of gas is a good visible practical sign in the experiment on the conservation of matter in the reaction. As the magnesium disappears with an increased input of hydrochloric acid, the balloon gets bigger showing that more hydrogen is evolved from the reaction;
2HCL + Mg MgCl2 + H2
Explanation:
Species present are 
, 
and 
. Now, we will calculate the number of componenets present as follows.
C = n - E
where, E = number of independent equations
n = number of phases present
Therefore, we will calculate the number of components as follows.
C = 3 - 1
= 2
Since, sodium chloride (NaCl) will tend to form a homogeneous mixture in water. Therefore, phase will be equal to 1.
Therefore, it means that there are two components present in one phase.
Molar mass of sodium chloride is 22.99 g/mol (Na+) + 35.45 g/mol (Cl-) = x g/mol. Then take the mass of sodium chloride sample 5 grams and divide by molar mass to get the number of moles. Take this number and multiply it by Avogadro’s number (6.22*10^23 molecules/mol). You now have the amount of molecules in 5 grams of NaCl.
Answer:
3.89 kg P2O5 must be used to supply 1.69 kg Phosphorus to the soil.
Explanation:
The molecular mass of P2O5 is
P2 = 2* 31 = 62
O5 = 5 *<u> 16 = 80</u>
Molecular Mass = 142
Set up a Proportion
142 grams P2O5 supplies 62 grams of phosphorus
x kg P2O5 supplies 1.69 kg of phosphorus
Though this might be a bit anti intuitive, you don't have to convert the units for this question. The ratio is all that is important.
142/x = 62/1.69 Cross multiply
142 * 1.69 = 62x combine the left
239.98 = 62x Divide by 62
239.98/62 = x
3.89 kg of P2O5 must be used.
