Manipulation of the independent variable should change the dependent variable, the value of which "depends" on the independent variable's change in value.
Answer:
heat energy is released into the surrounding
The ion composition of Magnesium is 12,10, 2+.
Magnesium is a chemical element with symbol Mg and an atomic number 12, it has 12 protons, and 12 electrons with a chemical configuration of 2:8:2. It requires to loose two electrons to form a stable configuration forming a cation (positively charged ion) with a charge of +2 and a configuration of 2:8 ( 12 protons and 10 electrons).
CaCO3 + 2KCL ⇒ CaCl2 + K2CO3
It is balanced as so based on the charges given on the periodic table and polyatomic ions.
Calcium has the charge of 2 but CO3 also shares the same charge, thus cancelling that out.
Potassium has a charge of 1 while Chlorine also shares a charge of 1, also cancelling it out.
Thus, if it performs a double replacement reaction, they would take these charges to the new elements that do not cancel out their charges.
Therefore, we need the coefficient of 2 in front of Potassium Chloride in order to balance the equation as on the products side of the equation, Potassium and Chlorine both have a subscript of 2.
Hope this helps!