[kiwibop]

Hey! I'm hoping someone out there can help me out with these two questions.

A.) 1.25 mL of 1.50 M calcium nitrate is mixed with 1.10 mL of 2.00 M sodium oxalate. What's the concentration of the sodium ions in the resulting solution assuming the volumes are additive?

What I attempted:
calcium nitrate + sodium oxalate --> CaC₂O₄ + Na₂(NO₃)₂
# mols calcium nitrate: .0018 mol
# mols sodium oxalate: .0020 mol
total volume: .00235 L

Assuming that I'm on the right track, I can't figure out how to put it all together


Now with this other question I'm not completely sure if I even wrote the right side correctly. Also, I'm not sure how to figure out the second question.

B.) What will occur when solid calcium sulfate is added to water? When equilibrium is established, will there be any sulfate ions in the water?

What I think the equation is:
CaSO₄ + H₂O --> Ca(OH)₂ + H₂SO₄

Thanks in advance!

[AWK]

calcium nitrate + sodium oxalate --> CaC2O4 + 2NaNO3

CaSO4 = Ca²⁺(aq) + SO₄^2-(aq)

[Borek]

A.) 1.25 mL of 1.50 M calcium nitrate is mixed with 1.10 mL of 2.00 M sodium oxalate. What's the concentration of the sodium ions in the resulting solution assuming the volumes are additive?

What I attempted:
calcium nitrate + sodium oxalate --> CaC₂O₄ + Na₂(NO₃)₂

You don't need any reaction equation to solve the question - sodium ions are spectators only. This is simple dilution.

B.) What will occur when solid calcium sulfate is added to water? When equilibrium is established, will there be any sulfate ions in the water?

CaSO₄ is very weakly soluble, thus only traces will be dissolved - but otherwise there is no difference between dissolution of - say - NaCl.

[AWK]

CaSO4 is very weakly soluble, thus only traces will be dissolved - but otherwise there is no difference between dissolution of - say - NaCl

Solubility of CaSO4 in water is low indeed, but I disagree that 2 g/liter can be called "traces'