Oxybenzone is an effective sunscreen whose structural formula ...

Question

Oxybenzone is an effective sunscreen whose structural formula is shown.

b. What is the molecular formula and molar mass of oxybenzone?

Accepted Answer

All right. Hi, everyone. So this question says that the structure of Ketoprofen is shown below. It is a drug used to relieve muscle aches and reduce fever, determine the molecular formula and calculate the molar mass of keto profin. Here we have four different answer choices, proposing different molecular formulas as well as different molar masses for this compound. So in this case, the first thing we're going to do here is find the molecular formula of the compound because recall that the molar mass of a compound is calculated by using the molecular formula. Now, in this case, we are given a line structure of Ketoprofen or a skeletal structure. Recall that in a skeletal structure, carbon atoms are not actually shown instead, corners and open ends are implied to be carbon atoms. Now, hydrogen atoms that are connected to carbon atoms are also not shown rather, they're implied to be present in order to complete the number of bonds carbon requires. For example, considering the carbons inside of these benzene rings that do not have other substituents, these would have one implied hydrogen to fulfill the four bonds that carbon requires and so on. So in this case, carbons and hydrogens connected to carbons are implied, but other elements like oxygen allergens, et cetera do always have to be shown. So in the molecular formula recall that the molecular formula showcases what types of elements are present and the quantity of each in the compound itself. So in this case, we have only three types of elements, we have carbon hydrogen and oxygen. So in this case, before I go ahead and count my carbons, I'm going to first add the implied hydrogens. As discussed previously, the carbons of benzene rings that do not have other substituents are implied to have one hydrogen to ensure that they have all four bonds that carbon atoms require. On the other hand, tertiary oteo carbons will have one hydrogen as well. Whereas primary carbons like this methyl carbon over here will have three. Now, in this case, the car bono carbons or the carbons that are double bonded to oxygen atoms would not have additional hydrogens because those happen to have four bond already. So in this case, if I go ahead and count the number of corners and open ends in my structure, I have two rings with six carbons each. So it's 12, I have two carbons from the two car bottles and I have two more in between the benzene ring on the right side and the carboxylic acid group. So this gives me a total of 16 carbon atoms. And so if I count my hydrogens I have five hydrogens from one benzene ring for from the other three from a primary carbon, one from a tertiary carbon and another attached to the oxygen of my carboxylic acid. And so when I add together 5431 and one, I get a total of 14 hydrogens in this compound. And lastly is the number of oxygens which I can see is three right two from the Carboni and another from the oh group of the carboxylic acid. So when I put all of this information together, my molecular formula is co C 16 H 1403, where the quantities of each element are written as a subscript in the molecular formula. So now let's go ahead and talk about finding the molar mass of a compound. Recall that the molar mass of a compound is the total mass of all atoms present. So in this case, we're going to have to use the molar mass of each element according to the periodic table. Recall it for carbon that is 12.01 g per mole. For hydrogen, it is 1.008 g per mole and for oxygen, it is 16.00 g per M. So the reason why the molecular formula is important for finding the molar mass of a compound is because the molar mass of each individual element must be multiplied by the number of that element present in the compound. So because I have 16 carbons in my structure. For example, I will take the molar mass of carbon and multiply this by 16. And so this gives me 192 0.16 g per mole for carbon specifically. So now I will take the molar mass of hydrogen and multiply it by the quantity of hydrogens in my compound which is 14 and so 1.008 g per mole multiplied by 14 gives me 14.112 grams per mol. And last but not least is oxygen. I will take the molar mass of oxygen and multiply this by three because I have three oxygen atoms present in my compound. And so 16.00 g per mole multiplied by three gives me 48.00 g per mole. So my last step is to go ahead and add all of these numbers together. 192.16 added to 14.112 added to 48.00 gives me a total sorry total molar mass of 254 0.27 g per month. And there you have it based on this information. My answer is going to be option C in the multiple choice because the molecular formula of Ketoprofen is C 16 H 1403 and the molar mass is 254.27 g per mole. So with all that being said, thank you so very much for watching. And I hope you found this helpful.

Oxybenzone is an effective sunscreen whose structural formula is shown.
b. What is the molecular formula and molar mass of oxybenzone?

Key Concepts

Molecular Formula

Molar Mass

Structural Formula

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