Question

question: in the following skeleton reaction or unbalanced reaction, 0.350M K2S reacts with 40.00 ml of 0.415 M AgNO3. show calculations please

K2S(aq) + AgNO3(aq) → KNO3(aq) + Ag2S(s)

a) how many moles of AgNO3 has reacted?

b)how many moles of K2S has reacted?

c) how many milliliters of K2S must have been used?

Answer 1

The balanced equation is

K2S (aq) + 2AgNO3(aq) -----> 2KNO3(aq) + Ag2S(s)

a)

Molarity = Number of moles per liter of solution

Volume of AgNO3 solution used = 40.00ml

Molarity of AgNO3 solution = 0.415 mol/L

Number of moles of AgNO3 = (0.415mol/1000ml)×140.00ml = 0.0166mol

b)

From the balanced euation we know that 2 moles of AgNO3 reacts with 1mole of K2S

So,

0.0166 moles of AgNO3 reacts with 0.0166/2 = 0.0083moles of K2S

Therefore,

Number of moles of K2S reacted = 0.0083moles

c)  

Volume of K2S solution reacted = ( 1000ml/0.350mol)× 0.0083mol = 23.71ml