When the generalized variable of pressure is discussed, the symbol P is used. There are three different units of pressure used in chemistry. This is an unfortunate situation, but we cannot change it. You must be able to use all three. You will find more on pressure units in another page.
Standard pressure is defined as one atm.
There is no such thing as standard volume, although you will probably learn about molar volume in your class. Typically, if grams are used, you will need to convert to moles at some point.