How many grams of o2(g) are needed to completely burn 39.1 g of c3h8(g)?

The formula is
CxHy+(x+y/4)O2=xCO2+yH2O
the molecular weight of C3H8 is 44 gm so according the formula (5*32)gm O2 are needed to completely burn 44gm C3H8 so for 39.1 gm C3H8 we needed (39.1*32*5)/(44) = 142.181 gm

Ametal with a large number of free flowing electrons most likely has good conductivity

Answer : option a) 84explanation :

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.