Which of the following pairings of pH and hydronium ion concentration is correct? A: pH = 7.0; [H3O+] = 1 x10^–7

B: pH = 2.0; [H3O+] = 1 x10^2

C: pH = 9.0; [H3O+] = 9 x10^–9

D: pH = 3.0; [H3O+] = 3 x10^–11

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

i think is conclusions.i think so

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.