Synthesis of Alum Prelaboratory Assignment Name and Drawer...

Synthesis of Alum Prelaboratory Assignment Name and Drawer Number 1. Calculate the molar mass of the aluminum alum that is formed in Reaction (9-3). Notice that this alum is a hydrate so that a stoichiometric amount of water is included in the alum crystals and must be included in the total molar mass. Show the calculation. 2. In a particular experiment alum is synthesized according to the overall reaction shown in Reaction (9-3) starting with 0.213 g of Al and an excess of the other chemical reactants. (a) Determine the theoretical yield of alum formed in the reaction. (b) Calculate the percent yield of alum if the actual mass of alum obtained is 3.408 g. Show all of the calculations for both part (a) and part (b).

Transcript

00:01 Hello students, let's begin with this question.

00:03 In this question firstly we have to find out the molar mass of the alum.

00:09 So it will have this formula.

00:11 So the molar mass this is the sum of the individual atoms that are present in a compound.

00:18 So here the molar mass of the alum is equals to the molar mass of the potassium plus the molar mass of the aluminum plus if we see there are two sulphurs.

00:38 So there are two into molar mass of sulphur plus there are eight oxygen plus eight into the molar mass of oxygen.

00:49 Then there are 12 water molecules.

00:51 So 12 into molar mass of water.

00:55 So now substituting the values of the molar masses.

00:59 So molar mass of potassium is 39 .10 gram per mole and the molar mass of aluminum is 26 .98 gram per mole and the molar mass of sulphur is 2 multiply by 32 .07 gram per mole.

01:16 Then 8 oxygen 8 multiply by 16 .00 gram per mole.

01:21 There are 12 water molecules 12 into 18 .02 gram per mole.

01:27 So when we solve this we get here the molar mass of the alum which is equals to 474 .46 gram per mole.

01:40 Now in the next part here now the mass of aluminum is given which is equals to 0 .213 gram and here the reaction is two moles of aluminum it will react with the two moles of potassium hydroxide plus four moles of h2so4 plus two moles 22 moles of water and this will result to formation of the alum two moles of the alum.

02:13 So and along with it it will release the three moles of h2 gas.

02:21 So now here we have to find out the actual mass of alum.

02:24 So now for this firstly we have to find out the moles of the aluminum...

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