Enthalpy of formation is calculated by subtracting the total enthalpy of formation of the reactants from those of the products. This is called the HESS' LAW.
ΔHrxn = ΔH(products) - ΔH(reactants)
Since the enthalpies are not listed in this item, from reliable sources, the obtained enthalpies of formation are written below.
ΔH(C2H5OH) = -276 kJ/mol
ΔH(O2) = 0 (because O2 is a pure substance)
ΔH(CO2) = -393.5 kJ/mol
ΔH(H2O) = -285.5 kJ/mol
Using the equation above,
ΔHrxn = (2)(-393.5 kJ/mol) + (3)(-285.5 kJ/mol) - (-276 kJ/mol)
ΔHrxn = -1367.5 kJ/mol
<em>Answer: -1367.5 kJ/mol</em>
Answer: Option (A) is the correct answer.
Explanation:
Force acting on a dam is as follows.
F = 
.......... (1)
Now, when we double the depth then it means H is increasing 2 times and then the above relation will be as follows.
F' = 
F' = 
........... (2)
Now, dividing equation (1) by equation (2) as follows.
= 
Cancelling the common terms we get the following.
= 
4F = F'
Thus, we can conclude that if doubled the depth of the dam the hydrostatic force will be 4F.
When a substance absorbs thermal energy, it partitions some as potential and some as kinetic energy. Specific heat is an expression related to the quantity of heat a substance stores as potential energy; the remainder is absorbed as kinetic which causes the temperature to increase - recall that temperature is a measure of average kinetic energy.
When specific heat is low, most of the energy is partitioned as kinetic energy and the substance will experience the greatest temperature change.
So rather than calculating the change in temperature, we can simply inspect the specific heats. The one with the lowest will experience the greatest temperature change. We could also compare the specific heats: Al = .897/.385 ==> 2.3, Fe = .452/.385 = 1.2, Cu = .385/.385 = 1. We can expect Copper's temperature change to be 2.3 times larger than Aluminum's and 1.2 times larger than Iron's.
Answer:
False
Explanation:
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Answer:
HI (aq) → H⁺ (aq) + I⁻ (aq)
HI (aq) + H₂O(l) → H₃O⁺ (aq) + I⁻ (aq)
Explanation:
The Arrhenius acid concept indicates that a substance behaves like acid if it produces hydrogen ions H⁺ or hydronium ions H₃O⁺ in water. A substance will be classified as a base if it produces OH⁻ hydroxide ions in water. This way of defining acids and bases works well for aqueous solutions.
When we mix HI (aq) and water, we are increasing [H₃O⁺]
HI (aq) → H⁺ (aq) + I⁻ (aq)
HI (aq) + H₂O(l) → H₃O⁺ (aq) + I⁻ (aq)
