how many moles of hydroxide ions are there in 82.35 mL of a 2.164M Sr(OH)2 solution?
i understand how to do the math for problems like these, but i don't know how to find the moles of just hydroxide ions.
So you know to do M x L = moles Sr(OH)2.
To find the OH^- alone, that is just twice the moles Sr(OH)2 BECAUSE there are two OH^- per mole Sr(OH)2. To find Sr alone, that is just 1 x (the same) as moles Sr(OH)2.
To find moles Mg in Mg3(PO4)2.
find moles Mg3(PO4)2, then double that to find PO4^-3, triple it to find Mg^+2, double to find moles P and multiply by 8 to find moles O. Got it??
To find the number of moles of hydroxide ions in a solution, you need to consider the stoichiometry of the compound involved.
In this case, you have a solution of Sr(OH)2. The formula of Sr(OH)2 shows that there are two hydroxide ions (OH-) for every one Sr2+ ion.
To calculate the number of moles of hydroxide ions in the solution, you can follow these steps:
1. Convert the volume of the solution from milliliters (mL) to liters (L):
82.35 mL ÷ 1000 = 0.08235 L
2. Calculate the number of moles of Sr(OH)2 using the molarity (concentration) of the solution:
moles of Sr(OH)2 = molarity × volume in liters
moles of Sr(OH)2 = 2.164 M × 0.08235 L
3. Multiply the moles of Sr(OH)2 by the stoichiometric coefficient of the hydroxide ion to find the moles of hydroxide ions:
moles of hydroxide ions = moles of Sr(OH)2 × 2
By applying these calculations:
moles of Sr(OH)2 = 2.164 M × 0.08235 L = 0.1783044 moles
moles of hydroxide ions = 0.1783044 moles × 2 = 0.3566088 moles
Therefore, there are 0.3566088 moles of hydroxide ions in 82.35 mL of a 2.164 M Sr(OH)2 solution.