Ba(OH)2 and Water Reaction

[Dahlia Kirov 3A]

Hi!

I got stuck on a problem where we're given 0.43 grams of Ba(OH)2 and asked to calculate its molar concentration, the molar concentration of Ba2+,and the moral concentrations of OH- and H3O+ in an aqueous solution (0.100L) . Would someone mind explaining how to set up the chemical reaction for this problem?

[Michelle Yeung 3I]

You would start by writing out the balanced chemical equation of the reaction between Ba(OH)2 and H20: Ba(OH)2 (aq) + H2O (l) -> Ba+ (aq) + 2OH-(aq)
From this, you can find the molar ratios. Since there are 2OH- for each Ba(OH)2, you can multiply the Ba(OH)2 concentration (calculate by finding molar mass of Ba(OH)2 and calculating mol/L) by 2 to find the molar concentration of OH-. Next, you would use the conversions of [OH-][H3O+]=10^-14 and to find the [H3O+]