In a group assignment, students are required to fill 10 beakers with 0.720 M CaCl2. If the molar mass of CaCl2 is 110.98 g/mol and each beaker must have 250. mL of solution, what mass of CaCl2 would be used

They must weight 199.76 g of Ca and dilute it in a flask of 2.5 L.

Explanation:

We need to prepare the whole solution and at the end we will slip it in 10 beakers.

Data:

Number of beakers to prepare: 10

Each beaker requires: 250 mL

Total solution volume to prepare = Vt = 10 beakers * 250 mL = 2500 mL = 2.5 L

First step:

We need to use Molarity formula to get amount of solute to weight for the whole solution (Vt = 2.5 L)

Molarity  (M)  formula is:

where:

M: concentration of the solution expressed in Molarity (mol/L)

mol CaCl2: amount of solute expressed in mol

Vt: total volume of the solution to be prepared. Volume must be expressed in liters (L)

Step 2: Calculate amount of solute

We know concentration of the solution (M = 0.720 M) and also we know total volumen (Vt), then we will despejate mol of CaCl2 (quantity of solute):

Now we need to use molar mass of Ca (110.98 g/mol) to transform mol of in grams of :

Finally, this group of students must weight 199.76 g Ca and dilute it in a flask of 2.5 L, then they will prepare a solution of Ca 0.72M.   Then must be placed 250 mL of prepared solution in each beaker.

consider the reaction below.

 no rx

at 500 k, the reaction is at equilibrium with the following concentrations.

[pci5]= 0.0095 m

[pci3] = 0.020

[ci2] = 0.020 m

what is the equilibrium constant for the given reaction?

0.042

0.42

2.4

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