Answer:
A heatwave occurs when a system of high atmospheric pressure moves into an area and lasts two or more days.
Explanation:
In such a high-pressure system, air from upper levels of our atmosphere is pulled toward the ground, where it becomes compressed and increases in temperature.
Enthalpy change is the difference between energy used and energy gained. The change in enthalpy of the liquid mercury is 0.0231 kJ.
<h3>What is the enthalpy change?</h3>
Enthalpy change is the difference between the energy used to break chemical bonds and the energy gained by the products formed in a chemical reaction.
The enthalpy change is given by,

and,

Given,
Mass of the liquid mercury (m) = 11.0 gm
The specific heat of mercury (c) = 0.14 J per g per degree Celsius
Temperature change = 15 degrees Celsius
Enthalpy change is calculated as:

Therefore, 0.0231 kJ is the change in enthalpy.
Learn more about enthalpy change here:
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Answer is: the hydronium ion concentratio is 1.71×10⁻⁷ mol/dm³ and pH<6.76.
The Kw (the ionization constant of water) at 40°C is 2.94×10⁻¹⁴ mol²/dm⁶ or 2.94×10⁻¹⁴ M².
Kw = [H₃O⁺] · [OH⁻].
[H₃O⁺] = [OH⁻] = x.
Kw = x².
x = √Kw.
x = √2.94×10⁻¹⁴ M².
x = [H₃O⁺] = 1.71×10⁻⁷ M; concentration of hydronium ion.
pH = -log[H₃O⁺].
pH = -log(1.71×10⁻⁷ M).
pH = 6.76.
pH (potential of hydrogen) is a numeric scale used to specify the acidity or basicity an aqueous solution.
Answer:
D. Electron pairs repelling each other push atoms apart
Explanation:
Hope this helps :) I just got it wrong on ap3x so I'm sure this is right