Hemoglobin is a large molecule that carries oxygen in the body. An aqueous solution that contains 2.61 g of hemoglo- bin in 100.0 mL has an osmotic pressure of 7.52 mmHg at 25 °C. What is the molar mass of the hemoglobin? Assume hemoglobin does not dissociate in water. (LO 13.15) (a) 1.96 * 103 g>mol (b) 84.8 g/mol (c) 6.45 * 104 g>mol (d) 3.65 * 103 g>mol

Video transcript

Hello everyone today we are being given the falling problem. Myoglobin is an oxygen binding molecule in the muscles and has a structure similar to hemoglobin and a quick solution containing 2.5 g of myoglobin per 90 mL solution was found to have an osmotic pressure of 7.25 millimeters per mercury at 25 degrees Celsius determine the molar mass of myoglobin. So first we want to recall our formula for osmotic pressure. It is that are osmotic pressure is equal to our morality. Times are gas constant, times our temperature. So what we need to do from this is we need to derive our formula using some conversion factors. So what we can take from this is we can say the morality is equal to the mass over our Mueller mass of myoglobin over our molar mass divided by our volume time is the gas constant times our change in temperature. And when we rearrange this we get that the molar mass is equal to the mask of a myoglobin, times our gas constant, times the temperature over our osmotic pressure, times our volume. So before we do this we have to set our units correctly. So we need to change our temperature from Celsius to kelvin. So we have our 25°C. and to convert that to Kelvin. We simply add to 17 or to 73. to give us 2 98 0.15 Calvin. We already have our osmotic pressure which was 7. mm per mercury. However, we will need to convert this and we'll do that at a later time. We have our gas constant which is stands for our which is 0.08206 leaders times atmospheres over moles per kelvin. So we have our values that we can use for this. And then of course we have our mass last but at least we have our mass which was 2.5 g Putting this together. We have our 2.5g times our gas constant Times our temperature which is to 98.15 Kelvin. We divide this by our morality which is 7.25 millimeters per mercury. However, we need to convert this into atmospheres. So we used the conversion factor that one atmospheres is equal to 7 60 millimeters per mercury and then lastly multiplied by our volume which was mL. However, We can convert that 90 ml by usually the conversion factor that one ml equal to 10 to the negative third leaders to give us 0.09 L. And when this is all said and done, we get an answer of 7.1242 times 10 to the fourth grams per mole as our final answer. Overall, I hope that this helped. And until next time