# IDH 11

1. (a) How many atoms are in a 127.6 mg sample of Au? (b) How many moles of Au is this? (c) What is the total mass (in grams) of these atoms?
2. You have 21.4 g of pure CO2 molecules in a container.
(a) How many C (carbon) atoms are there in this container?
(b) What mass (in grams) of pure water would contain the same number of water molecules as carbon atoms in the container of CO2 ?
3. Clorox germicidal bleach contains 8.25% sodium hypochlorite (NaClO). You have exactly 5 cups of this bleach in a container. How many Cl (chlorine) atoms are in the container.
4. You have 2.3 liters of gas at a pressure of 5.3 atm, and temperature of 45 0C. What will the temperature of the gas be if you decrease the volume of gas to 1.2 L, and decrease the pressure to 2.5 atm ?
5. You are a fermenting glucose to make wine, and notice at Noon that 730 mL of CO2 gas was produced at 37 and 1 atm pressure in your system. What would the final volume (in liters) of the gas produced be when you measured later that evening at 26 and 660 mmHg, if the amount of gas did not change?

6. A gas mixture used in a hospital has a total pressure of 4.3 atm. If the mixture contains 5.1 moles of nitrogen and 1.2 moles of oxygen, what is the partial pressure, in atmospheres, of each separate gas in this mixture?
7. Calculate the initial volume (in mL) of the most concentrated solution indicated below that is needed to prepare each of the following diluted solutions:
(a) 225 mL of 4.0% (m/v) glucose solution using a 20.0% (m/v) glucose solution.
(b) 45.0 mL of a 0.5% (m/v) CaCl2 solution using a 4.0% CaCl2 solution.
(c) 450.0 mL of a 0.90% (m/v) NaCl solution using a 4.0% (m/v) NaCl solution.