What is the mass of solute in each of the following solutions? (a) 2.25 L of 0.200 M FeCl3 (b)

What is the mass of solute in each of the following...

Key Concepts

Unit Conversions

Unit conversions, such as converting volume units (e.g., milliliters to liters), are essential in chemistry to ensure that calculations are done with consistent units. This step is necessary so that the formula for molarity (moles per liter) is correctly applied in quantitative analyses.

Molar Mass

Molar mass is the mass of one mole of a substance, typically expressed in grams per mole (g/mol). It is used to convert between the number of moles and the mass of a substance, making it crucial for determining the mass of solute in a solution.

Molarity

Molarity is a concentration measure representing the number of moles of solute per liter of solution. This concept is fundamental for preparing and diluting solutions in chemistry, as it allows scientists to relate the amount of a chemical substance to the volume of the solution it occupies.

Mole Concept

The mole is a standard unit in chemistry used to quantify the amount of a substance. It provides a bridge between the atomic scale and macroscopic quantities, enabling the calculation of the number of particles in a given sample based on its mass or volume.

Transcript

00:02 In this question, we need to determine the mass of solute in a specific solution.

00:06 The volume of the solution is given as well as the molar concentration.

00:12 Now, number a, we're working with iron chloride, an iron chloride solution with a molar concentration of 0 .2 .0 molar, and we have a volume of 2 .25 liters.

00:27 So i need to work out the mass of the iron chloride in the end.

00:35 So the number of grams of iron chloride.

00:40 And i have a volume of 2 .25 liters of solution that i start off with here.

00:49 So i'm going to put that over one.

00:51 And then i need to get rid of the liter unit here.

00:57 So the way i'm going to do that is by.

00:59 Multiplying by a unit factor.

01:02 One of the unit factors of the molar concentration.

01:06 Now i've written two molar unit factors down here so that we can choose one of these.

01:14 I need to divide by the number of liters, so i'm going to take the first unit factor.

01:20 So i'm going to put 0 .200 moles of ion, chloride here at the top and at the bottom i will have per one liter of solution.

01:39 Right.

01:42 Then it's easy to see that i will get rid of the liter unit but now i'm sitting with a number of moles here and i need to end with grams.

01:57 So the only way i can get rid of the number of moles is by multiplying by the molar with the molar mass of iron chloride.

02:09 So that's going to be 162 .20 grams of iron chloride per every one mole of iron chloride.

02:25 So this is the molar mass of iron chloride.

02:30 And here you can now see that the number of moles will.

02:35 Cancel out and i will end with mass in terms of grams.

02:41 So if i do this calculation, i get a value of 73 .0 grams of iron chloride.

02:53 Right.

02:54 So let's move on to number b.

02:57 Number b i will do the same, go through the same procedure.

03:03 So here i have, sorry, this is not supposed to.

03:06 To be 2 .25 grams.

03:10 It's supposed to be liters.

03:14 They give us the volume and the molar concentration of potassium per iodate.

03:24 Right.

03:25 So we need to end up with a certain mass of potassium per iodate in terms of grams.

03:34 I want to finish with some value in terms of grams of potassium per iodate.

03:44 And for this purpose, let's start off with 2 .25 liters of the solution that we have here.

03:52 That is given.

03:55 So i'm going to put that over 1.

04:01 And then i need to multiply with one of these unit factors here, which comes from the molar concentration of the potassium per iodate that was given.

04:14 And i can see that if i multiply with the first one, i will be able to get rid of the liter unit.

04:21 So i'm going to say 0 .2 .00 moles of potassium per iodate over 1 liter of solution.

04:35 So this is the molar concentration of potassium iodate...

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