Tutor profile: Abhinav R.
Subject: Organic Chemistry
In lab, you react 1-propene with 1 equivalent of hydrochloric acid. What is the IUPAC name of the product?
2-chloropropane. When you treat an alkene with an acid, the pi-pond pulls the hydrogen atom off of the hydrochloric acid (HCl) due to electronegative differences. The hydrogen atom either adds to the less substituted side of the alkene or rearranges so that the resulting positive charge on the newly formed alkane is on the most substituted carbon. Since the alkane is positively charged, it will react with the conjugate base (in this case it is a chloride ion) and form a bond. As a result, the chloride atom will add to the more substituted carbon of the previously existing alkene. When we apply this idea to 1-propene we are left with 2-chloropropane. When naming, remember that we want to first find the longest parent carbon chain and then name the substituents relative to their positioning on this chain.
Subject: Basic Chemistry
Jake wants to make hot cocoa. He warms 100mL of milk in a pot and then adds 15 grams of cocoa powder. If the molar mass of the cocoa powder is 100 grams/mol, what is the concentration of Jake's hot cocoa (in M)?
1.5 M or 1.5 moles of cocoa powder/liters of milk. To solve this problem, recall that the concentration of a solution is measured as moles of solute/liters of solvent. We are given the volume of solvent in mL, so we can convert that to liters by using the conversion factor of 1 L (liter)/1000mL. If we do so, we find that Jake has 0.1 L of warm milk. To calculate the moles of solute, we need to convert the 15 grams of cocoa powder into moles of cocoa powder. This can be done by dividing the mass of cocoa powder (15g) by the molar mass or molecular weight of cocoa powder (which is given to us as 100 grams/mol). The quotient gives us 0.15 moles of cocoa powder. If we plug these values back into the formula for the concentration of a solution (moles of solute/liters of solvent) we can find the concentration of Jake/s hot cocoa to be 1.5 M.
During the day, plants are able to synthesize sugars, such as glucose, that sustain them and are vital to their survival. In their thylakoids, the organelle responsible for making these sugars, which protein is responsible for harvesting this light AND splitting water?
Photosystem II. Recall that photosynthesis is split into two distinct processes, one dependent on the presence of light and one independent from its presence. The light dependent reactions use proteins along the thylakoid membrane called photosystems to harvest light energy using a pigment called chlorophyll. Recall that between the two types of photosystem proteins present on the thylakoid membrane, only one of them is capable of splitting water into hydrogen protons and half a molecule of oxygen. That protein is photosystem II.
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