Answer:
0.366m = Molality of the solution
Explanation:
To solve this question we must know the addition of a solute produce decreasing in freezing point regard to the pure solvent. The equation is:
ΔT = m*Kf*i
<em>Where ΔT is change in freezing point </em>
(As freezing point of water is 0°C, the ΔT is 2.72°C)
<em>Kf is freezing point depression constant = 1.86°C/m for water</em>
<em>i is Van't Hoff factor. The number of ions produced when 1 mole of the salt is dissolved = 4 ions for Fe(ClO₃)₃, Fe³⁺ and 3 ClO₃⁻ ions</em>
<em>m is molality of the solution.</em>
<em />
Replacing:
2.72°C = m*1.86°C/m*4
<h3>0.366m = Molality of the solution</h3>
<em />
Number<span> of protons found in the nucleus of an </span>atom<span>.</span>
Answer:
165 of CO₂.
Explanation:
In the reaction:
Na2CO3 + 2HCl → 2NaCl + CO2 + H2O
2 moles of HCl reacts producing 1 mole o CO₂
If 7.5 moles of HCl reacts, moles of CO₂ produced are:
7.5 moles of HCl ₓ ( 1 mol CO₂ / 2 mol HCl) = 3.75 mol CO₂. As molar mass of CO₂ is 44g/mol, mass of CO₂ is:
3.75 mol CO₂ ₓ (44g / 1mol) = <em>165 of CO₂ </em>
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)
D because these are the biggest particles, and are therefore, the most dense.