What is the pH of a 5.5 × 10⁻⁶ M HBr solution?

Asample of the male sex hormone testosterone, c19h28o2, contains 3.88×10^21 atoms of hydrogen.(a) how many atoms of carbon does it contain? (b) how many molecules of testosterone does it contain? (c) how many moles of testosterone does it contain? (d) what is the mass of this sample in grams?

Which position represents spring in the southern hemisphere? a) b) c) d)

If two atoms are bonded to a central atom with no lone pairs, how will they be arranged