00:01
Hello students in this question we are given with the molecular formula of aspirin and its molecular formula is hc9 h7 -04.
00:14
This is the molecular formula and using this molecular formula we can find out the molecular mass also which is equal to 1 plus 9 multiplied by 12 since 12 is the atomic mass of carbon plus 1.
00:33
Multiplied by 7 we have 7 hydroger and 1 is the mass of hydrogen plus 16 which is the mass of oxygen multiplied by 4 so overall we get it as 180 grams so aspirin has a molecular formula hc9 h7 04 with a molecular mass of 180 gram sorry molar mass of 180 gram so now let's move ahead for the first question in the first question we have to find out the number of moles in 325 mg of aspirin so we know that 1 mole of aspirin is equivalent to 180 grams in mass so now how many moles will be there if the mass is 325mg of aspirin in that tablet so 325mg you have to convert it into grams it will become 0 .0.
01:41
325 grams.
01:43
So now we will do the cross multiplication.
01:46
So x equal to 0 .325 multiplied by 1 mole divided by 180 grams.
01:55
So from here we get the value of x as 1 .8 multiplied by 10 to the power minus 3 moles.
02:04
So we have 1 .8 multiplied by 10 to the power of minus 3 moles.
02:04
So we have 1 .8 multiplied by 10 to the power of minus 3 moles in 3.
02:10
M g of aspirin.
02:12
Now moving towards the second part of this question.
02:17
It says that how many molecules are there in this mass.
02:21
So we know that one mole is equivalent to 180 gram of aspirin which is again equivalent to avogadro's number of molecule which is 6 .022 multiplied by 10 to the power of 23 molecules.
02:40
Now we have to find out if the mass is 0 .3 to grams how many molecules will be there.
02:47
So again we will do the cross multiplication and after doing the cross multiplication we will get the answer of molecules as 1 .087 multiplied by 10 to the power of 21 molecules.
03:05
So this is the second answer...