Magnesium has atomic no 12
Electronic configuration given by
Or
Answer: 
Explanation:
Heat of reaction or enthalpy change is the energy released or absorbed during the course of the reaction.
It is calculated by subtracting the enthalpy of reactants from the enthalpy of products.

= enthalpy change = ?
= enthalpy of products
= enthalpy of reactants
For the given reaction :



Answer:
Number of moles = 0.94 mol
Explanation:
Given data:
Number of moles of sodium chloride = ?
Volume of sodium chloride = 1.25 L
Concentration of solution = 0.750 mol/L
Solution:
Formula:
Concentration = number of moles/ volume in L
By putting values.
0.750 mol/L = number of mole / 1.25 L
Number of moles = 0.750 mol/L×1.25 L
Number of moles = 0.94 mol
Matter - anything with mass and occupies space
accuracy - an indication of how close a measurement is to the correct result
precision - the degree to which a measurement can be replicated
meniscus - the curved top surface of a liquid column
volume - spaced occupied measured in cubic units
density - mass of an object per unit volume