Rate constant for a second order reaction

The rate constant for the second-order reaction is 0.80/M*s at 10 degrees C 2NOBr(g) goes to 2NO(g) + Br2 (g) (a) Starting with a concentration of 0.071 M, calculate the concentration of NOBr after 25 seconds (b) Calculate the half-life when [NOBr]0 =0.081M (c) Find the half-life when [NOBr]0=0.047

Back-calculating Ksp values when solubilities are known?

I want to calculate the Ksp values for 3 carbonate compounds when the solubilities are known. K2CO3 = 112 g/100 ml Na2CO3 = 30 g/100 ml CaCO3 = .001 g/100 ml For CaCO3 I understand how to set up the solubility equation as: [Ca^+2][CO3^-2]/[CaCO3] But I always get confused about di-protic compounds like K2CO3 and Na2CO3. So, can you show me the simple way of calculating the Ksp's for these 3 compounds when the solubilities are given as I have provided. Please show the solubility equation and math associated.

Equilibrium

The equilibrium constant for Kc for the reaction shown is 54.3 at 430 degrees C. H2(g) = I2(g) = 2 HI(g) At the start if the reaction there are 0.714 moles of H2, 0.984 mole of I2 and 0.886 mole of HI in a 2.00 liter reaction chamber. At equilibrium, what are the concentrations of the gases- [H2] [I2] and [HI] ?

Balanced Equations

1. Write the balanced equation for the first step in the reaction between vinegar and baking soda, with carbonic acid (H2CO3) as a product. What type of reaction is this? 2. Write the balanced equation for the second step in the reaction, the liberation of carbon dioxide from carbonic acid. What type of reaction is this? 3. Write the combined, balanced equation for the complete chemical reaction between vinegar and baking soda.

Differences between aluminum sulfate and aluminum hydroxide as a flocculant in water treatment?

Can aluminum sulfate and aluminum hydroxide be used interchangeably as a flocculant and have the same effectiveness when attempting to floc various cations and anions that are in the form of dissolved solids? Or does the presence of the SO4^-2 ion vs. the OH^-1 ion have more floc capability because of its larger ionic charge??