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?

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.

To balance the given chemical equations, you need to ensure that the number of each type of atom is the same on both sides of the equation. Here's the balanced form of the equations you provided:

1. Ca(OH)2 + H2SO4 -> CaSO4 + 2H2O
2. Na2S2O3 + I2 -> 2NaI + Na2S4O6
3. ZnCl2 + Na2S -> ZnS + 2NaCl
4. SnCl4 + 2H2O -> SiO2 + 4HCl (Assuming there is a typo, and it should be SiO2 instead of SnO2)

Now, let's look at the phase labels and compound format:

In the molecular equation form, you usually write the compounds using their chemical formulas without specifying the state of matter. However, you might include the phase labels in parentheses if necessary. Here's how the phase labels could be added:

1. Ca(OH)2(aq) + H2SO4(aq) -> CaSO4(aq) + 2H2O(l)
2. Na2S2O3(aq) + I2(aq) -> 2NaI(aq) + Na2S4O6(aq)
3. ZnCl2(aq) + Na2S(aq) -> ZnS(s) + 2NaCl(aq)
4. SnCl4(aq) + 2H2O(l) -> SiO2(s) + 4HCl(aq)

The phase labels indicate the state of matter for each substance involved: (aq) for aqueous (dissolved in water), (s) for solid, and (l) for liquid.

Regarding the compound format, you chose correctly to keep Ca(OH)2 together instead of separating into separate ions (Ca+2 and 2OH-). Ionic equations are used when the compounds dissociate into ions in a solution, which is not the case for Ca(OH)2.

In the case of Pb(NO3)2 + 2NaBr -> PbBr2 + 2NaNO3:
- The molecular equation is already correct.
- The ionic equation represents the dissociation of each compound into its ions:
Pb(NO3)2(aq) + 2Na+(aq) + 2Br-(aq) -> PbBr2(s) + 2Na+(aq) + 2NO3-(aq)
- The net ionic equation removes the spectator ions that appear on both sides:
Pb2+(aq) + 2Br-(aq) -> PbBr2(s)

For Na2CO3 + MgBr2, the molecular equation is already correct.
- The ionic equation is:
2Na+(aq) + CO3^2-(aq) + Mg2+(aq) + 2Br-(aq) -> 2Na+(aq) + 2Br-(aq) + MgCO3(s)
- The net ionic equation is:
CO3^2-(aq) + Mg2+(aq) -> MgCO3(s)

So, to summarize, in this set of equations, the compounds chosen correctly to stay together are Ca(OH)2, PbBr2, and MgCO3. The phase labels for the molecular equation could be represented as (aq) for dissolved substances and (s) for solids.

Let's go through each balanced equation and determine the correct phase labels for the compounds involved:

1. Ca(OH)2 + H2SO4 → CaSO4 + 2H2O
- Ca(OH)2 is a white solid, so it is written as (s) for solid.
- H2SO4 is a liquid, so it is written as (l) for liquid.
- CaSO4 is a white solid, so it is written as (s) for solid.
- H2O is a liquid, so it is written as (l) for liquid.

Therefore, the phase labeling for the molecular equation would be:
Ca(OH)2 (s) + H2SO4 (l) → CaSO4 (s) + 2H2O (l)

2. Na2S2O3 + I2 → 2NaI + Na2S4O6
- Na2S2O3 is a white solid, so it is written as (s) for solid.
- I2 is a purple solid, so it is written as (s) for solid.
- NaI is a white solid, so it is written as (s) for solid.
- Na2S4O6 is a white solid, so it is written as (s) for solid.

Therefore, the phase labeling for the molecular equation would be:
Na2S2O3 (s) + I2 (s) → 2NaI (s) + Na2S4O6 (s)

3. ZnCl2 + Na2S → ZnS + 2NaCl
- ZnCl2 is a white solid, so it is written as (s) for solid.
- Na2S is a solid, so it is written as (s) for solid.
- ZnS is a black solid, so it is written as (s) for solid.
- NaCl is a white solid, so it is written as (s) for solid.

Therefore, the phase labeling for the molecular equation would be:
ZnCl2 (s) + Na2S (s) → ZnS (s) + 2NaCl (s)

4. SnCl4 + 2H2O → SiO2 + 4HCl
- SnCl4 is a liquid, so it is written as (l) for liquid.
- H2O is a liquid, so it is written as (l) for liquid.
- SiO2 is a solid, so it is written as (s) for solid.
- HCl is a gas, so it is written as (g) for gas.

Therefore, the phase labeling for the molecular equation would be:
SnCl4 (l) + 2H2O (l) → SiO2 (s) + 4HCl (g)

Regarding the choice of compound to keep together, you have made the correct choices in all four balanced equations.