Part II. Each question is worth 6 points.
[1] A student adds 9.00 g of dry ice (solid CO2) to an empty balloon. What will be the volume of the balloon a
STP after all the dry ice sublimes?



Answer :

To find the volume of the balloon at standard temperature and pressure (STP) after all the dry ice sublimates, we will follow these steps: 1. Calculate the number of moles of CO2. 2. Apply the ideal gas law to find the volume at STP. Step 1: Calculate the number of moles of CO2 The number of moles (n) of CO2 can be calculated using the formula: n = mass / molar mass Given that the mass of dry ice added to the balloon is 9.00 g and the molar mass of CO2 is 44.01 g/mol, we can calculate the moles of CO2 as follows: n = mass_dry_ice / molar_mass_CO2 n = 9.00 g / 44.01 g/mol n ≈ 0.2045 mol So we have approximately 0.2045 moles of CO2. Step 2: Apply the ideal gas law to find the volume at STP The ideal gas law is stated as: PV = nRT Where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin. At standard temperature and pressure (STP), the pressure (P) is 100 kPa (which is equivalent to 101,325 Pa) and the temperature (T) is 0°C, which is 273.15 K in Kelvin. Given: - P = 101325 Pa - n ≈ 0.2045 mol (from step 1) - R = 8.314 J/(mol·K) (ideal gas constant) - T = 273.15 K We want to find V, so we rearrange the formula to solve for V: V = nRT / P Substituting the constants and the value of n we calculated: V = (0.2045 mol) * (8.314 J/(mol·K)) * (273.15 K) / (101325 Pa) Now we calculate the volume: V ≈ (0.2045) * (8.314) * (273.15) / (101325) V ≈ (463.637535 mol·K·J/(mol·K)) / (101325 Pa) V ≈ 4.574 m^3 To convert this volume from cubic meters to liters, we use the conversion factor where 1 cubic meter is equivalent to 1000 liters: V_liters = V_m^3 * 1000 liters/m^3 V_liters ≈ 4.574 * 1000 V_liters ≈ 4574 liters Therefore, the volume of the balloon at STP after all the dry ice sublimates will be approximately 4574 liters.