Answer:
a
. eight tenths of her cookies
Explanation:
Let the total number of Lakesha's cookies be represented by x.
So that;
She gave three tenths to Bailey = 
of x
= 
She gave five tenths to Helen = 
of x
= 
Fraction of Lakesha's cookies given away = +
= 
= 
Thus, the fraction of cookies given away by Lakesha is 
.
Answer:
Explanation:
2AgNO3 + CaCl2 ----> 2AgCl + Ca(NO3)2
Molarity = moles of solute/volume of solution in liters.
From this relation, we can figure out the number of moles of solute by multiplying the molarity of the solution by the volume in liters.
We have 53.1 mL, or 0.0531 L, of a 12.5 M, or 12.5 mol/L, solution. Multiplying 12.5 mol/L by 0.0531 L, we obtain 0.664 moles. So, in this volume of solution, there are 0.664 moles of solute (HCl).
Magnesium Peroxydisulphate with formula of MgS₂O₈.
<h3><u>Explanation:</u></h3>
The question clearly stands on the concept of molarity and atomic weights.
The atomic weight of magnesium = 24.
The atomic weight of sulphur = 32.
The atomic weight of oxygen = 16.
The amount of magnesium present = 0.248 g
The amount of sulphur present = 0.665 g.
The amount of oxygen present = 1.31g.
So, moles of magnesium present = 0.01 moles.
Moles of sulphur present = 0.02 moles.
Moles of oxygen present = 0.08 moles.
So, mole ratio of the compound as magnesium : sulphur : oxygen = 1:2:8.
So the compound is Magnesium Peroxydisulphate with formula of MgS₂O₈.
