Răspuns:
Explicație:
react. Na2SO4
cu Pb (NO3 )2
rezulta 18,18 g precipitat
Se cere :
masele de reactanti=?
xg yg 18,18g
Na2SO4 + Pb(NO3)2 = 2NaNO3 + PbSO4
142g 331g 303 g
x= 142 . 18,18 : 303= 8, 52 g Na2SO4
n= 8,52g : 142 g/moli=0,06 moli Na2SO4
y= 331 . 18,18 : 303=19, 86 g PbSO4
n= 19,86g : 303g/moli=0,065 moli PbSO4
M Na2SO4= 2.23 + 32 + 4.16= 142----> 142g/moli
M Pb(NO3)2= 207 + 2.14 + 6.16=331------> 331g/moli
MPbSO4= 207 + 32 + 4.16= 303-------> 303g/moli