Consider the following reaction:

Li2S(aq)+Co(NO3)2(aq)-->2LiNO3(aq)+CoS(s)

What volume of 0.150 M Li2S solution is required to completely react with 125 mL of 0.150 M Co(NO3)2?

To calculate the volume of the Li2S solution required, we need to use the stoichiometry of the reaction and the given molarities of the solutions.

First, let's write out the balanced chemical equation:

Li2S(aq) + Co(NO3)2(aq) --> 2LiNO3(aq) + CoS(s)

According to the balanced equation, 1 mole of Li2S reacts with 1 mole of Co(NO3)2 to produce 2 moles of LiNO3 and 1 mole of CoS.

Given that the molarity (M) of Li2S solution is 0.150 M and the volume of Co(NO3)2 solution is 125 mL (0.125 L), we can use this information to calculate the number of moles of Co(NO3)2:

moles of Co(NO3)2 = Molarity × Volume
moles of Co(NO3)2 = 0.150 M × 0.125 L
moles of Co(NO3)2 = 0.01875 moles

Since the stoichiometric ratio between Li2S and Co(NO3)2 is 1:1, we know that the number of moles of Li2S required will also be 0.01875 moles.

Now, let's calculate the volume of the Li2S solution using its molarity:

Volume of Li2S solution = moles of Li2S / Molarity
Volume of Li2S solution = 0.01875 moles / 0.150 M
Volume of Li2S solution = 0.125 L or 125 mL

Thus, you need 125 mL of the 0.150 M Li2S solution to completely react with 125 mL of the 0.150 M Co(NO3)2 solution.

To find the volume of the Li2S solution required, you can use the stoichiometry of the reaction.

First, let's write the balanced equation:

Li2S(aq) + Co(NO3)2(aq) → 2LiNO3(aq) + CoS(s)

From the balanced equation, you can see that 1 mole of Li2S reacts with 1 mole of Co(NO3)2.

Step 1: Calculate the moles of Co(NO3)2.

Given: Volume of Co(NO3)2 solution = 125 mL = 0.125 L
Concentration of Co(NO3)2 solution = 0.150 M

Moles of Co(NO3)2 = Concentration × Volume
= 0.150 M × 0.125 L
= 0.01875 moles

Step 2: Determine the moles of Li2S required.

From the balanced equation, it can be observed that the stoichiometric ratio between Li2S and Co(NO3)2 is 1:1.

Therefore, moles of Li2S required = 0.01875 moles

Step 3: Convert moles of Li2S to volume.

Given: Concentration of Li2S solution = 0.150 M

Using the formula: Moles = Concentration × Volume
Volume = Moles / Concentration

Volume of Li2S solution required = 0.01875 moles / 0.150 M
= 0.125 L or 125 mL

Therefore, you would need 125 mL of the 0.150 M Li2S solution to completely react with 125 mL of 0.150 M Co(NO3)2.

Just follow the steps in this worked example. Remember moles = M x L.

http://www.jiskha.com/science/chemistry/stoichiometry.html