Question

Calculate the millimoles of solute in 2.25 L of a 0.00645 M NaCN solution. millimoles: mmol NaCN Calculate the millimoles of solute in 275 mL of a 8.89 ppm CaCO 3 solution. millimoles: mmol CaCO 3

Answer 1

To calculate the millimoles of solute in a solution, multiply the moles of solute by 1000. Use the formula millimoles = moles × 1000. For the NaCN solution, the millimoles of solute is 14.5 mmol, and for the CaCO3 solution, it is 2.44 mmol.

Step-by-step explanation:

To calculate the millimoles of solute in a solution, we need to use the formula:

millimoles = moles × 1000

First, we need to calculate the moles of solute by multiplying the molarity (M) by the volume (L). Let's calculate it for each solution:

(a) For the NaCN solution:

moles = molarity × volume = 0.00645 M × 2.25 L = 0.0145 moles

millimoles = 0.0145 moles × 1000 = 14.5 mmol

(b) For the CaCO3 solution:

Since the concentration is given in ppm, we need to convert it to M:

Concentration in M = (ppm ÷ 1000) × (1 mol/L) = (8.89 ppm ÷ 1000) × (1 mol/L) = 8.89 × 10^-6 M

moles = molarity × volume = 8.89 × 10^-6 M × 0.275 L = 0.00244 moles

millimoles = 0.00244 moles × 1000 = 2.44 mmol

Answer 2

Answer: The millimoles of solute in 2.25 L of a 0.00645 M NaCN solution is 14.5 millimoles. The millimoles of solute in 275 mL of a 8.89 ppm
`CaCO_3` solution is 0.0244 millimol.

Step-by-step explanation:

Molarity is defined as the number of moles of solute dissolved per liter of the solution.

`Molarity=(n)/(V_s)`

where,

n= moles of solute

`V_s` = volume of solution in L

1) For 0.00645 M NaCN

`0.00645 M=(n)/(2.25L)`

`n=0.0145mol=14.5millimoles`
`1mol=10^(3)millimol`

2) For 8.89 ppm

`ppm=\frac{\text {Mass in mg}}{\text {Volume in L}}`

`8.89=\frac{\text {Mass in mg}}{0.275L}`

`{\text {Mass in mg}}=2.44`

Moles of
`CaCO_3=\frac{\text {given Mass in g}}{\text {Molar Mass}}=(2.44* 10^(-3))/(100g/mol)=2.44* 10^(-5)mol=0.0244millimol`
`1mol=10^(3)millimol`