What needs to be done in order to balance this equation? *Hint...count the atoms of each element. Only compare like elements! HCl + Ba → BaCl2 + H2
Question 3 options:

Place a 2 in front of the HCl and a 2 in front of the Ba.

Place a 2 in front of the Ba.

It is already balanced.

Place a 2 in front of the HCl.

number of molecules / avogadro's number * molecule molecular = mass

explanation:

we define a gram-molecular weight as the mass of one mole of any element or compound. a mole contains avogadro's number of units (molecules) –  

6.022

x

10

23

. so, dividing the number of molecules by avogadro's number gives us the number of moles. multiplying that by the molecular weight gives us the mass. from the periodic table we find the gram-molecular weight of u to be238 and of f to be19. so,  

u

f

6

will have a gram-molecular weight of 352g.

i would say b

explanation:

but i think i would need more information than that

since electrons are negative the answer is neagtaive

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.