Question

How many moles of Sr2+ are present in 250 mL of a 0.45 M solution of strontium phosphide?

Answer 1

Moles of Sr²⁺ = 0.3375

Further explanation

Molarity is a way to express the concentration of the solution

Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

$\large{\boxed {\bold {M ~ = ~ \frac {n} {V}}}$

Where

M = Molarity

n = Number of moles of solute

V = Volume of solution

So to find the number of moles can be expressed as

$\boxed{\bold{n=V\times M}}$

Strontium phosphide (Sr₃P₂)

Sr₃P₂ ⇒ 3Sr ²⁺ + 2P³⁻

• mol of Sr₃P₂

$\tt 0.45~M \times 0.25~L=0.1125$

• mol of Sr ²⁺

mol ratio Sr₃P₂ : Sr ²⁺ = 1 : 3

$\tt \dfrac{3}{1}\times 0.1125=0.3375$