Answer
$mass(g) = 8.867\times 10^{- 3}$
Work Step by Step
1. Calculate [OH^-]:
pH + pOH = 14
10.5 + pOH = 14
pOH = 3.5
$[OH^-] = 10^{-pOH}$
$[OH^-] = 10^{- 3.5}$
$[OH^-] = 3.162 \times 10^{- 4}$
- $CaO(aq) + H_2O(l) \lt -- \gt Ca^{2+}(aq) + 2OH^-(aq)$
2. Since $CaO$ is a strong base that produces 2 OH for each molecule: $[OH^-] = 2 * [CaO]$
$ 3.162\times 10^{- 4} = 2 * [CaO]$
$ \frac{ 3.162\times 10^{- 4}}{ 2} = [CaO]$
$ 1.581\times 10^{- 4}M = [CaO]$
3. Calculate the number of moles:
$n(moles) = concentration(M) * volume(L)$
$n(moles) = 1.581\times 10^{- 4} * 1$
$n(moles) = 1.581\times 10^{- 4}$
4. Find the mass value in grams:
40.08* 1 + 16* 1 = 56.08g/mol
$mass(g) = mm(g/mol) * n(moles)$
$mass(g) = 56.08 * 1.581\times 10^{- 4}$
$mass(g) = 8.867\times 10^{- 3}$
