# IDH 7

Two moles of NaCl contains (a) ___2___ moles of Na ions, and ___2___ moles of Cl ions.
How many molecules of glucose (C6H12O6) are there in 0.045 moles of glucose?
0.223 moles of helium gas has a mass of ________ g.
What is the mass (in grams) of 0.0230 mol of caffeine, C8H10N4O2?
Fructose has the same formula as glucose, C6H12O6. How many molecules of fructose are there in 0.270 g of fructose?
How many atoms of gold (Au) are there in 1.35 grams of gold?
0.37 moles of pure water weigh _______ g ?
A 60.0 L tank of chlorine gas at 27 °C and 125 atm springs a leak. When the leak was discovered, the pressure was reduced to 50 atm. How many moles of chlorine gas escaped?
A 9.0 L volume of chlorine gas is heated from 27° C to 127° C at constant pressure. What is the final volume?
The temperature of a sample of an ideal gas in a sealed 5.0 L container is raised from 27 °C to 77 °C. If the initial pressure of the gas was 3.0 atm, what is the final pressure?
A balloon contains 7.2 L of He. The pressure is reduced to 2.00 atm, and the balloon expands to occupy a volume of 25.1 L. What was the initial pressure exerted on the balloon?

Carbon dioxide is formed when gasoline is burned. If 30.0 L of CO2 is produced at a temperature of 3,000° C and allowed to cool to room temperature (25.0° C) without any pressure changes, what is the new volume of the carbon dioxide?

What is the temperature in Celsius needed to change the pressure of 10.0 liters of a gas that has a pressure of 97.0 kPa at 25 C to standard pressure. Note standard pressure is 101.325 kPa = one atmosphere = 14.7 psi.
A gas syringe contains 42.3 milliliters of a gas at 98.15° C. Determine the volume that the gas will occupy if the temperature is decreased to -18.50° C.
Laboratory tests for a certain patient indicate their blood calcium level of 7.3 mEq/L. Calculate how many moles of calcium ion are in 0.65 L of the patient’s blood?
What is the mass percent of NaOH in a solution that is prepared by dissolving 25.0 g of NaOH in 115.0 g of H2O?

How many grams of NaOH are needed to prepare 65.0 g of a 17.0% (m/m) NaOH solution?