Question

How many molecules of water are you drinking if you were to consume 450mL bottle of H20? 1. What is the volume of water expressed in L and mL? 2. Calculate the mass of water in g (Hint: we did this in week 1) a. Express mass in mg and kg 3. Find/Calculate the molecular weight of water (H20) 4. Calculate how many moles of water are in the bottle (450mL) 5. Calculate how many molecules of water you would consume if you drank the whole bottle? Concentration (w/v), Whose tea is sweeter? You had 2 tsp of sugar in 7oz of water 1. Calculate how many molecules of sugar (sucrose, C12H22011) you have consumed Show your work. 2. Calculate the concentration of sugar in this cup of tea expressed in mg/ml. Mole, Molarity and Dilutions 1. You have a bottle with a liter of glucose solution at a concentration of 0.02 Molar. You transfer 100mL of this solution into a beaker a. This will cause the concentration of glucose solution in the bottle to i. Drop by a 10h ii. Increase 10 fold ii. Drop by a 100th iv. Increase 100 fold v. Stay the same b. The concentration of the glucose solution in the beaker will be i. 0.002 Molar ii. 0.2 Molar ii. 0.02 Molar iv. 2 Molar v. None of the above

lab

Answer 1

1 L = 1000 ML 1 ML = 10^-3 L Given that 450 mL = 450 times 10^-3 L Specific gravity of H_2O = 1 g/ml mass Kg = 450 ml times 1 mg/ml mass = 450 mg 1 kg = 10^6 mg mg = 10^-6 kg mass = 450 times 10^-6 kg molecular weight of H_2O = 2 times Atomic mass of H + 1 times Atomic mass of O = 2 times 1 + 1 times 16 = 2 + 16 = 18 moles = weight Gram molecular weight Gram molecular weight = 18.02 g/mol 450 ml of water. 1ml = 1g 450 g = 450 g/18.02 g/mol = 24.97 mol. How many molecules If we multiply moles per liter by Avogadro's number, the result is the number of molecules. A = 6.02 times 10^23 450/18 = 25 moles per kg = 25 times 6.09 times 10^23