# Tutor profile: Gloria V.

## Questions

### Subject: Organic Chemistry

Why is a carbonyl group? Can a carbonyl group have different functional groups? If so, how are the reactions different or the same?

A carbonyl group is a group of atoms that has a carbon double bonded to oxygen as well as two R groups. These R groups can be the same or different. The R groups can contain carbon groups like alkanes, oxygen, nitrogen, or, even, sulfur. Depending on these R groups, the carbonyl group could be a carboxyl acid ( one R being -OH), one R being alkyl group), amide (one R being NH2, NHR', NR'R"), aldehyde (one R being H, one R being an alkyl group), ketone (both Rs being alkyl groups), ester (one R being OR' and the other R being an alkyl group), thioester (one R being SR', and the other R being an alkyl group), plus many other groups including those related to carboxyl acids. Each of these groups will have their own preferred reactions based on the hydrogen bonds, dipole-dipole interactions, electronegativies of the atoms, and electron-poor/rich atoms. For example, many of the carboxyl acids groups will react similarly while the thioester and aldehyde groups will react differently because the carboxyl groups have many of the same atoms while the thioester and aldehyde groups have very different electron-poor/rich atoms and electronegativies.

### Subject: Chemistry

How many grams of water are produced from 32 grams of oxygen?

Looking at the problem, we need to calculate the number of grams of water from the number of grams of oxygen. To solve this we first need a reaction equation in order to find out how much water is produced from oxygen: H2 + O2 -> H2O Looking at equation, it is not balanced because there are 2H and 2 O on the left and only 2 H and 1 O on the right. To balance, we need the same number of Hs and Os on each side. First, let's balance the Os since H is already balanced. To make the Os balance, we will need to put a 2 in front of H2O H2 + O2 -> 2H2O Now, we have 2H and 2 O on the left but 4 H and 2 O on the right. So, we need to balance the H next. Let's put a 2 in front of H2. 2H2 + O2 -> 2H2O Now, we 4H and 2 O on the left and 4H and 2 O on the right. So, our equation is balanced. Since our equation is balanced, we can now calculate the grams of water from the grams of oxygen. The next part is similar to algebra. In chemistry, we call it stoichiometry where we use information to change one thing into another thing, like 12 inches into 1 foot or 1000 meters into 1 kilometer. The basic formula is this: grams of substance X to moles of substance X to moles of substance Y to grams of substance Y. Confused? If so, this concept can be difficult to understand without lots or practice. Think of it as converting points in a video game into buying something needed to advance to the next level or the amount of money that you need to spend in order to to get rewards points for a gift card or special prize. First we will convert the grams of oxygen into the moles of oxygen. Looking at the periodic table, one mole of O is 16 grams. Since we have 32 gram of oxygen, we will have 2 moles or 32 grams of oxygen * 1 mole of oxygen/ 16 grams of oxygen = 2 moles of oxygen. If you look, you will see that the grams of oxygen cancel since we have grams of oxygen on top and grams of oxygen on bottom, leaving mole of oxygen. Next, we will convert the moles of oxygen into the moles of water. We do this by using a molar fraction. We get the molar fraction from the balanced reaction equation that we did above. We had 1 mole of oxygen produce 2 moles of water. Now, you might be asking but we just got 2 moles of oxygen in the last part. To understand this, think of it as before, you have 1000 points in a video game but you only need 500 points to advance through each level. This means that 1000 points times 1 level/500 points or you can get through 2 levels since 1000 * 1/500 = 2 and points cancel out, leaving only level left. So: 2 moles of oxygen * 2 moles of water/1 moles of oxygen equals 4 moles of water. The moles of oxygen will cancel out. The next step is converting the moles of water into grams of water. This step will be similar to the first step that we did in converting. We know that water has 18 grams in one mole since water has 2 grams of hydrogen ( 2 moles of H) and 16 grams of oxygen (1 mole of O). So: 4 moles of water * 18 grams of water/1 mole of water = 64 grams of water. The moles of water will cancel each other out. To write it all out: 32 grams of oxygen * 1 mole of oxygen/16 grams of oxygen* 2 moles of water/1 mole of oxygen* 18 grams of water/1 mole of water or 32 *(1/16) * (2/1) * (18/1) = (32*2*18)/16 = 64 So 32 grams of oxygen will produce 64 grams of water.

### Subject: Algebra

Gerald and Jennifer are mirror image twins. Gerald is right-handed and loves orange and Jennifer is left-handed and loves yellow. They are looking for schools supplies and have gotten everything except scissors and notebooks. There are seven times more right-handed scissors than left-handed scissors and three times more yellow notebooks than orange notebooks. If there is a total of 16 orange and yellow notebooks and a total of 24 pairs of scissors left, how many notebooks and scissors did Gerald get to pick from?

There are a lot of words in this problem so first we need to understand what we need to find out. Looking at the last few words, we need to figure out how many items Gerald could pick from. From the second sentence, we know that Gerald is right-handed and loves orange. Now that we know what need to figure out. We need to plan how to get the answer. Let's start by picking out the numbers and their related facts. We see that there is a total of 16 notebooks and a total of 24 scissors. We also know that there are 7 times more right-handed scissors and 3 times more yellow notebooks. So, how can we relate the numbers and the facts to solving the problem? Well, with totals, we know that 16 = ____ & 24 = _____ Now, we need to put numbers and letters to figure out the number of each item. Since we know that there are 7 times more right handed scissors than left-handed scissors. Let's label the left-handed scissors as X. Then, the number of right-handed scissors will be 7 times that number or 7X. Similarly, we will label the orange notebooks and yellow notebooks. So, let's label the orange notebooks as Y. Then, the number of yellow notebooks will be 3Y since there are three times more yellow notebooks than orange notebooks. Now, let's combine the facts. Since there are 24 pairs of scissors and 7X pairs of right-handed scissors and X pairs of left-handed scissors, we can add 7X + X together and have 7X + X = 24. Next, let's solve for X. The first thing we need to do is add up the X. Since 7+ 1 = 8, 7X + 1X = 8X. So, 8X = 24. Next we divide. Or, 8X/8 = 24/8 or X = 3. Similarly, we will do this for the notebooks: 16 notebooks = the total Y = orange notebooks 3Y = yellow notebooks 3Y + Y = 16 3 + 1 = 4 or 3Y + 1Y = 4Y 4Y = 16 Divide 4Y/4 = 16/4 Y = 4 The number of left-handed scissors is X or 3 and the number of right-handed scissors is 7*3 or 21. The number of orange notebooks is Y or 4 and the number of yellow notebooks is 3*Y or 12. Going back to what we need to solve, we know that Gerald loves orange and is right-handed. So, we need to get the number of orange items and the number of right-handed items. From above, we had 21 pairs of right-handed scissors and 4 orange notebooks. To find the number of items that Gerald got to pick from, we will need to add these two numbers together or 21 + 4. So, Gerald got to pick from 25 items in total.