Question

Balance the following:
Ca(OH) + H2SO4 -----> CaSO4 + H2O
Na2S2O3 + I2 -----> 2NaI + Na2S4O6
ZnCl + Na2S -----> ZnS + NaCl
SnCl4 + H2O ----> SiO2 + 4HCl

I figured out the 2nd and 4th one to be:
2Na2S2O3 + I2 -----> 2NaI + Na2S4O6
SnCl4 + 2H2O -----> SiO2 + 4HCl *Is there a typo in this one with Sn or Si? It was given like this on the handout.

Molecular Equation: Pb(NO3)2 + 2NaBr -----> PbBr2 + 2NaNO3
Ionic Equation: Pb+2 + (NO3)-1 + 2Na+1 + 2Br-1 -----> PbBr2 + 2Na+1 +2(NO3)-1
Net Ionic Equation: Pb+2 + 2Br-1 -----> PbBr2

Molecular Equation: Na2CO3 + MgBr2 -----> 2NaBr + MgCO3
Ionic Equation: 2Na+1 + (CO3)-2 + Mg+2 + 2Br-1 -----> 2NaBr + Mg+2 + (CO3)-2
Net Ionic Equation: 2Na+1 + 2Br-1 -----> 2NaBr

What are the phase labels on the molecular equation and did I choose the correct compound to keep together? Would the phase labels be (Aq) for each one and then (S) for the one staying together?

Answer 1

Ca(OH) + H2SO4 -----> CaSO4 + H2O

There is a typo Ca(OH)2 ; balancing is then easier.

Ca(OH)2 + H2SO4 -----> CaSO4 + 2H2O


2Na2S2O3 + I2 -----> 2NaI + Na2S4O6


ZnCl + Na2S -----> ZnS + NaCl

another typo here should be ZnCl2 which again make balancing easier

ZnCl2 + Na2S -----> ZnS + 2NaCl


SnCl4 + H2O ----> SiO2 + 4HCl
another typo, from the equation I would say that the LHS is SiCl4

SiCl4 + 2H2O ----> SiO2 + 4HCl

Rather a lot of typos on one handoout.


Pb(NO3)2(aq) + 2NaBr (aq) -----> PbBr2 (s) + 2NaNO3(aq)

so your net ionic equation as

Pb+2(aq) + 2Br-1(aq) -----> PbBr2 (s)

is fine



Na2CO3(aq) + MgBr2(aq) -----> 2NaBr(aq) + MgCO3(s)

you have the wrong net ionic equation.