A10.00l sample of gas has a mass of 11.92g at stp. what is the molar mass of the gas?

Let's assume that the gas is an ideal gas.

1 mole of ideal gas has the volume as 22.4 L at STP (273 K , 1 atm)

The given gas has 10.00 L. Hence we can find out the moles of gas.

moles in 22.4 L gas = 1 mol
moles in 10.00 L gas =  = 0.446 mol

moles = mass / molar mass

hence, molar mass = mass / moles
                               = 11.92 g / 0.446
                               = 26.73 g/mol

Hence, the molar mass of the gas is 26.73 g/mol

Heat is involved in chemical change in two ways; chemical changes either result in heat being added to or removed from an object, and chemical changes require a certain amount of heat before they can take place.