Heat in the mantle comes from the Earth's molten outer core, decay of radioactive elements and, in the upper mantle, friction from descending tectonic plates.The temperature difference between the upper and lower boundaries of the mantle requires heat transfer to occur.
Material heating up in the mantle
Thermometer with black bulb because black reflects less heat than white
HA is a weak acid so there should be little amount of HA and then H+ and A- in the beaker so the last one is true a weak acid never converts completely to H+ and A-
Answer:

Explanation:
2NO₂ ⇌ N₂O₄
E/mol·L⁻¹: 0.058 0.012
K_{\text{eq}} = \dfrac{\text{[N$_{2}$O$_{4}$]}}{\text{[NO$_{2}$]$^{2}$}} = \dfrac{0.012}{0.058^{2}} = \mathbf{3.6}
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\text{The $K_{\text{eq}}$ value would be $\boxed{\mathbf{3.6}}$}