Answer:
Cabon-12 has same average atomic weight and mass number.
Explanation:
carbon-12 has average atomic weight 12 amu and mass number of 12.
amu represents average of mass of a nucleon.
As carbon-12 has same average atomic mass and mass number therefore carbon-12 is a good standard to determine average mass of a nucleon.
Again, abundance of carbon-12 isotope is almost equal to 99%. Therefore fluctuation of average atomic weight from 12 amu is very very low.
So, carbon-12 is taken as a standard to determine mass of a nucleon.
Hence atomic mass of carbon-12 is 12 amu.
<span>The composition of a fertilizer is usually express in NPK number. NPK number is in terms of Percent by mass of the said element which are Nitrogen, Phosphorus and Potassium. A 15-35-15 fertilizer has 15%
Nitrogen, 35% Phosphorous, and 15% Potassium by mass. If you have 10 g of this
fertilizer, to get the number of moles of phosphorus, you multiply the mass by
35%, which is equal to 10*0.35 or 3.5 g phosphorus. Then you divide the
calculated mass of phosphorous by its molar mass which is 30.97 g/mol.
Therefore, you have 3.5/30.97 which is equal to 0.1130 mol Phosphorus. This is the amount of Phosphorus in moles in the fertilizer.</span>
Balanced chemical reaction:
MgSO₄(aq) + Sr(NO₃)₂(aq) → Mg(NO₃)₂(aq) + SrSO₄(s).
Ionic reaction:
Mg²⁺(aq) + SO₄²⁻(aq) + Sr²⁺(aq) + 2NO₃⁻(aq) → Mg²⁺(aq) + 2NO₃⁻(aq) + SrSO₄(s).
Net ionic reaction:
Sr²⁺(aq) + SO₄²⁻(aq) → SrSO₄(s).
Magnesium sulfate (MgSO₄), strontium nitrate (Sr(NO₃)₂ and magnesium nitrate (Mg(NO₃)₂) are soluble in water. Strontium sulfate (SrSO₄) is not soluble in water.
This chemical reaction is double displacement reaction - cations and anions of the two reactants switch places and form two new compounds.
