Best Answer
1 mole of a substance contains 6.022x10^23 "units" of that substance.
So 0.187 mol of Na+ is 1.13x10^23 ions (6.022x10^23 x 0.187).
Answer:
Mole fraction = 0,0166
Explanation:
Mole fraction is defined as mole of a compound per total moles of the mixture. In the solution, the solute is fructose and the solvent is water. That means you need to find moles of fructose and moles of water.
The molecular mass of fructose is 180,16g/mol and mass of water is 18,02 g/mol. Using these values:
91,7g fructose × (1mol / 180,16g) = <em>0,509 moles of fructose</em>
545g water × (1mol / 18,02g) = <em>30,24 moles of water</em>
Thus, mole fraction of fructose is:

<em>Mole fraction = 0,0166</em>
I hope it helps!
Answer:
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When ice melts, the physicals state changes from solid to liquid. The energy or the heat required (q) required to change a unit mass (m) of a substance from solid to liquid is known as the enthalpy or heat of fusion (ΔHf). The variables; q, m and ΔHf are related as:
q = m * ΔHf
the mass of ice m = 65 g
the heat of fusion of water at 0C = ΔHf = 334 J/g
Therefore: q = 65 g * 334 J/g = 21710 J
Now:
4.184 J = 1 cal
which implies that: 21710 J = 1 cal * 21710 J/4.184 J = 5188.8 cal
Hence the heat required is 5188.8 cal or 5.2 Kcal (approx)
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