1. Mass of flask, boiling chips, foil cap and unknown after cooling reaction 83.350g
2.Mass of flask, boiling chips,and foil cap. 82.657
3. water bath temperature C is 95.0 C
4. Barometric pressure inches of Hg 30.09
5. Accepted molar mass of unknown is 86.2g/moles
6. Volume of flask is 270 mls
Problem
1. Calculate mass of unknown.
2. Express water bath temperature in Kelvin
3. Express barometric pressure in standard atmospheric pressure
4. Express volume of flask in cm3
5. Calculate density of vaporized unknown.
Answers so far
1. 0.697 g
2. 368.15 K
3. 764.286
4. 270 cm3
5. How can I determine the vaporized unknown?
To determine the density of the vaporized unknown, you can use the ideal gas law equation: PV = nRT. This equation relates the pressure (P), volume (V), number of moles (n), gas constant (R), and temperature (T) of a gas.
In this case, you have the following information:
- Barometric pressure: 30.09 inches of Hg
- Volume of flask: 270 mL (which is already equivalent to 270 cm3)
- Water bath temperature: 95.0 °C (which corresponds to 95.0 + 273.15 = 368.15 K)
- Accepted molar mass of unknown: 86.2 g/mol
1. Calculate the number of moles (n) of the unknown:
Using the mass of the unknown (0.697 g) and its accepted molar mass (86.2 g/mol), you can calculate the number of moles:
n = mass / molar mass
n = 0.697 g / 86.2 g/mol
n ≈ 0.0081 mol
2. Calculate the density of the vaporized unknown:
To calculate the density (ρ), you need to know the mass (m) and the volume (V) of the gas.
Since the mass of the flask, boiling chips, foil cap, and unknown after cooling reaction together is 83.350 g, and the mass of the flask, boiling chips, and foil cap is 82.657 g, you can subtract these values to get the mass of the unknown gas:
mass of unknown = mass after cooling reaction - mass of flask, boiling chips, and foil cap
mass of unknown = 83.350 g - 82.657 g
mass of unknown ≈ 0.693 g
Now, you can calculate the density:
ρ = mass / volume
ρ = 0.693 g / 270 cm3
ρ ≈ 0.00257 g/cm3
To determine the density of the vaporized unknown, we need to use the ideal gas law equation, which states:
PV = nRT
Where:
P = pressure
V = volume
n = number of moles
R = ideal gas constant
T = temperature
To calculate the density, we need to rearrange the equation as follows:
density = (molar mass * pressure) / (gas constant * temperature)
Given values:
Pressure (P) = 30.09 inches of Hg (inHg)
Temperature (T) = 95.0°C (convert to Kelvin)
Molar mass of unknown substance = 86.2 g/mol
Volume of flask (V) = 270 mL (convert to cm^3)
Let's go step by step:
1. Convert the temperature from Celsius to Kelvin:
Temperature in Kelvin = Celsius temperature + 273.15
Temperature in Kelvin = 95.0°C + 273.15 = 368.15 K
2. Convert the volume of the flask from mL to cm^3:
Volume in cm^3 = 270 mL * 1 cm^3/mL = 270 cm^3
3. Convert the pressure from inches of Hg to standard atmospheric pressure:
Standard atmospheric pressure at sea level = 760 mmHg or 1 atm
Pressure (inHg) = 30.09 inHg
Pressure (atm) = Pressure (inHg) / (29.92 inHg/atm) = 30.09 inHg / 29.92 inHg/atm ~= 1.004 atm
4. Calculate the density:
density = (molar mass * pressure) / (gas constant * temperature)
density = (86.2 g/mol * 1.004 atm) / (0.0821 L.atm/mol.K * 368.15 K)
density = 86.777 g/L
Therefore, the density of the vaporized unknown substance is approximately 86.777 g/L.