Magnetizing steel is a physical change, not a chemical change.
The double replacement reaction
<h3>Further explanation</h3>
Given
Reaction if Na₂S + HCl
Required
Type of reaction
Solution
The double replacement reaction occurs when there is a displacement of the cations and anions of the reactants involved in the reaction to form two new compounds.
The general formula for this reaction :
AB + CD ⇒ AD + CB
At the bottom of the reaction, it is shown the number of atoms of each compound in the reactants and products which indicates the application of <em>the law of conservation of mass</em>, that the number of atoms in the reactants will be the same as the number of atoms in the product, so the reaction is said to be in a balanced state.
B: dna cells should be the answer
<span> ca. 0.4 moles. if this helps plz medal!</span>
Dalton's atomic theory was based on the law of conservation of mass which states that the matter can neither be created nor be destroyed but it can only transformed into one form or another. In a chemical reaction, total mass of the reactants will be equal to the total mass of the products.
Taking an example,
Mass of 
= 16g
Mass of 
= 
Total mass on reactant side = 
Total mass on reactant side = 80g
Mass of 
= 44g
Mass of 
Total mass on product side = 
Total mass on product side = 80g
It is seen from the above example that the
total mass on reactant side = total mass on product side.
