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)
Answer:
Result of the formation of positive and negative ions.
Answer:
3,85 g of Fe
Explanation:
1- The first thing to do is calculate the molar mass of the Fe2O3 compound. With the help of a periodic table, the weights of the atoms are searched, and the sum is made:
Molar mass of Fe2O3 = (2 x mass of Fe) + (3 x mass of O) = 2 x 55.88 g + 3 x 15.99 g = 159.65 g / mol
Then, one mole of Fe2O3 has a mass of 159.65 grams.
2- Then, the relationship between the Fe2O3 that will react and the iron to be produced. With the previous calculation, we can say that with one mole of Fe2O3, two moles of Fe can be produced. Passing this relationship to the molar masses, it would be as follows:
1 mole of Fe2O3_____ 2 moles of Fe
159.65 g of Fe2O3_____ 111.76 g of Fe
3- Finally, the calculation of the mass that can be produced of Fe is made, starting from 5.50 g of Fe2O3
159.65 g of Fe2O3 _____ 111.76 g of Fe
5.50 g of Fe2O3 ______ X = 3.85 g of Fe
<em>Calculation: 5.50 g x 111.76 g / 159.65 g = 3.85 g
</em>
The answer is that 3.85 g of Fe can be produced when 5.50 g of Fe2O3 react
Answer:
The potential energy decreases whereas the kinetic energy increases.
