Dealing with a 0.150 M Co (NO3) 2•6H2O. Determine the number of grams of Co (NO3) 2•6H2O that you would need to weigh out in order to prepare 100.00 mL of the solution

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Chemistry

10 July, 21:59

Dealing with a 0.150 M Co (NO3) 2•6H2O. Determine the number of grams of Co (NO3) 2•6H2O that you would need to weigh out in order to prepare 100.00 mL of the solution

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Hana Mercer · Answer 1

The correct answer is 4.3635 g

Explanation:

First, we have to calculate the molecular weight of the solute (Co (NO₃) ₂•6H₂O). For this, we obtain the molar mass of the elements from the Periodic Table (Co, N, O and H) and calculate as follows:

MW (Co (NO₃) ₂•6H₂O) = (1 x MM (Co)) + (2 x MM (N)) + ((2 x 3) x MM (O)) + ((6 x 2) x (MM (H)) + (6 x (MM (O)))

= (58.9 g/mol) + (2 x (14 g/mol)) + (6 x 16 g/mol) + (12 x 1 g/mol) + 6 x (16 g/mol)

= 290.9 g/mol

We have a solution 0.150 M Co (NO₃) ₂•6H₂O, so we can convert from mol/L to g/L if we multiply the concentration by the molecular weight as follows:

0.150 mol/L x 290.9 g / 1 mol = 43.635 g/L

Finally, we have to prepare a 100 ml solution. This volume is equal to 0.1 L, so we multiply the concentration in g/L by the volume in L and we obtain the mass we need to weigh:

mass = 43.635 g/L x 0.1 L = 4.3635 g

Addisyn Stokes · Answer 2

4.365g

Explanation:

We'll begin by calculating the number of mole of Co (NO3) 2•6H2O present in 100mL of 0.150 M Co (NO3) 2•6H2O solution. This is illustrated below:

Molarity = 0.150M

Volume of solution = 100mL

Recall: 1000mL = 1L

Therefore, 100mL = 0.1L

Mole of solute (Co (NO3) 2•6H2O) = ?

Molarity is simply mole per unit litre of solution. It is represented mathematically as:

Molarity = mole / Volume

Mole = Molarity x Volume

Mole of Co (NO3) 2•6H2O = 0.15x0.1

Mole of Co (NO3) 2•6H2O = 0.015mol

Now, we need to convert 0.015mol to grams in order to obtain the desired result. This is illustrated below:

Mole of Co (NO3) 2•6H2O = 0.015mol

Molar Mass of Co (NO3) 2•6H2O = 59 + 2[14 + (16x3) ] + 6[ (2x1) + 16] = 59 + 2[14 + 48] + 6[2 + 16] = 59 + 2[62] + 6 [18] = 59 + 124 + 108 = 291g/mol

Mass of Co (NO3) 2•6H2O = ?

Mass = number of mole x molar Mass

Mass of Co (NO3) 2•6H2O = 0.015 x 291

Mass of Co (NO3) 2•6H2O = 4.365g

Therefore, 4.365g of Co (NO3) 2•6H2O is needed to prepare 100mL of 0.150 M Co (NO3) 2•6H2O solution.