Considere as equações. :
i- al2o3+hcl> alcl3+h2o.
ii-so2+naoh> na2so3+h2o.
iii- bao4+hno> ba (no3)2+h2o+o2
a sequência correta dos coeficientes dos reagentes e produto necessários para o balanceamento estequiométrico dessa equação é:

i.
a) 6,3,3,2.
b)1,6,2,3
c)1,3,3,2
d)6,1,2,3
e)1,6,2,3

ii.
a)1,2,1,1
b)2,1,1,1,
c)2,1,2,2
d)2,1,2,2
e)1,2,1,1

iii

a)2,1,2,2,2
b)1,1,2,1,1
c)1,2,1,1,1
d)2,1,2,2,2
e)1,2,1,1,1

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%

atomic mass = 39

number of neutrons = 20

number of protons= 19

electronic configuration = 1s2 2s2 2p6 3s2 3p6 4s1

the number of electron in first shell = 2

number of electrons in n=3 shell = 8

the answer is c.the valence of the atoms combine .

answerlinnaeus;