Answer:
Option 3. The catalyst does not affect the enthalpy change (
) of a reaction.
Explanation:
As its name suggests, the enthalpy change of a reaction () is the difference between the enthalpy of the products and the reactants.
On the other hand, a catalyst speeds up a reaction because it provides an alternative reaction pathway from the reactants to the products.
In effect, a catalyst reduces the activation energy of the reaction in both directions. The reactants and products of the reaction won't change. As a result, the difference in their enthalpies won't change, either. That's the same as saying that the enthalpy change of the reaction would stay the same.
Refer to an energy profile diagram. Enthalpy change of the reaction measures the difference between the two horizontal sections. Indeed, the catalyst lowered the height of the peak. However, that did not change the height of each horizontal section or the difference between them. Hence, the enthalpy change of the reaction stayed the same.
Answer:
The maximum length of the specimen before deformation is 240.64 mm
Explanation:
Strain = stress ÷ elastic modulus
stress = load ÷ area
load = 2130 N
diameter = 3.4 mm = 3.4×10^-3 m
area = πd^2/4 = 3.142 × (3.4×10^-3)^2/4 = 9.08038×10^-6 m^2
stress = 2130 N ÷ 9.08038×10^-6 m^2 = 2.35×10^8 N/m^2
elastic modulus = 126 GPa = 126×10^9 Pa
Strain = 2.35×10^8 ÷ 126×10^9 = 0.00187
Length = extension ÷ strain = 0.45 mm ÷ 0.00187 = 240.64 mm
I believe the correct answer is D
Explanation:
The absolute temperature is the lowest possible temperature in the universe. At this temperature, all atoms become motionless and cease to move.
The value of the absolute zero is pegged at -273.16°C.
- It is the lowest limit of the coldness of a body.
- Nothing can be colder than a body at absolute temperature.
- Many researches are underway to take advantage of this temperature value for scientific purpose.
- Thermodynamically, all process stops at this temperature.
- When a body is brought close a body at absolute zero, it can suffer cryogenic burn due to heat transfer.
Answer is: Ksp = 4s³.
Balanced chemical reaction (dissociation) of strontium hydroxide:
Sr(OH)₂(s) → Sr²⁺(aq) + 2OH⁻(aq).
Ksp(Sr(OH)₂) = [Sr²⁺]·[OH⁻]².<span>
[</span>Sr²⁺] = s.<span>
[</span>OH⁻] = [Sr²⁺] = 2s<span>
Ksp = (2s)² · x = 4s³.
Ksp is the solubility product constant for
a solid substance dissolving in an aqueous solution.
[</span>Sr²⁺]
is equilibrium concentration of iumcations.<span>
[</span>OH⁻] is equilibrium concentration of hydroxide anions.
