A sample of 653 mL of drinking water is found to contain 38.0 mg Pb. What is this concentration in parts per million?

Agas diffuses 1/7 times faster than hydrogen gas (h2). what is the molar mass of the gas? 100.10 g/mol 98.78 g/mol 86.68 g/mol 79.98 g/mol

Match the mixture with the substance// i really need on this guys (it’s a pic btw)

What was bohr’s contribution to the planetary model