Convert 653 mmHg to SI units

If a polyatomic ionic compound has gained two hydrogen ions, then how does its name begin?

Answer asap need it by wednesday morning calculate the ph of 0.02m hcl best answer will be brainliest

How many moles of lead are in 1.50 x 10^12 atoms of lead? could you explain the answer as well and not just give it to me i am refreshing for finals and i need to know how to do it