A balloon of helium gas has a volume of 400 mL at 19°C if the balloon has cool to occupy 220 mL what is its temperature

law of conservation of matter

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.

sure im new too!

explanation:

you gotta add the following molecules so we can give u an answer

explanation: