Your answer is C - Melting of a substance
Answer:
The extraction is done by electrolysis. The ions in the aluminum oxide must be free to move so that electricity can pass through it. Aluminum oxide has a very high melting point (over 2000°C) so it would be expensive to melt it. Aluminum oxide does not dissolve in water, but it does dissolve in molten cryolite.
Explanation:
Answer:Calorimetry
Explanation: In this case, an instrument called Calorimeter is used to measure the amount of heat being transferred
Answer:
2.23 x 10^-4 mol
Explanation:
0°C =273 K
PV= nRT
n= PV/RT
n= (5.00 atm * 0.0010 L)/ (0.0821 * 273 K)
n= 2.23 x 10^-4
4Fe(s) + 3O2(g) → 2Fe2O3(s) ....... ΔH = -1.7 x 10^3 kJ
<span>shows that 1700 kJ of heat is released when 4 moles of Fe react. </span>
<span>Molar mass of Fe = 56 g/mol </span>
<span>Molar mass of Fe2O3 = 160 g/mol. </span>
<span>(a) When 4 mol ( 4 x 56 = 224 g) iron reacted 1700 kJ are released, </span>
<span>when 9.0 g Fe reacted, the amount of energy will be </span>
<span>(9.0 x 1700) / (224) = 68.3 kJ </span>
<span>(b) According to the equation, 1700 kJ of energy released during the formation of 2 moles of Fe2O3 which is 2 x 160 = 320 g of rust. </span>
<span>120 kcal x (4.18 kJ / 1 kcal) = 501.6 kJ </span>
<span>When 1700 kJ released = 320 g rust </span>
<span>when 501.6 kJ released = (501.6 x 320) / 1700 = 94.4 g rust</span>