How many moles are present in 281 grams of arsenic

The molar mass or As is 74.9g. Start with 281g multiply by (1mol/74.9g) = 3.75 mols

Put what you don’t want on the bottom (in this case grams) so they the u it’s cancel (if you multiply by grams and the divide by grams they cancel. Ultimately leave what you want on the top ( This case mols) then do the math

The  grandmother cell  is a hypothetical  neuronthat represents a complex but specific concept or object.[1]  it activates when a person "sees, hears, or otherwise sensibly discriminates"[2]  a specific entity, such as his or her grandmother. the term was in use at least as early as 1966 amongst staff and students in the department of experimental psychology, university of cambridge, england. a similar concept, that of the  gnostic neuron, was proposed two years later