What does the subscript in a chemical formula represent (the 2 in h2)?

Ibeg i need 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?

How do i complete this electrolysis of water lab? i’m at home, so i don’t have the materials, and the lab didn’t properly work and was incomplete at school.

Polar bears give birth and hunt on sea ice. which of the following would polar bears survive during the melting of arctic ice? growing another layer of fur during summer migrate inland to search for different food sources staying put until the ice refreezes sticking to the usual diet of seals