# Molecular Questions

Mike weighed his flask with the stopper, tube, and cap, and found it to be 236.2401 g. He hooked up the tubing and generated CO_{2} into the flask for 25 minutes and then weighed the flask again. The mass was now 236.3875 g.

After the experiment was over, he filled the flask with water and took the mass again, which was 496.76 g. The barometer in the room reads 1017 mbar and the temperature is 25.0 °C.

1. What is the mass of the water in his flask? |
g |

2. Assuming a density of water of 1.00 g/mL, what is the volume of water in his flask? |
mL |

3. What is the volume of his flask? |
mL |

4. Assuming a density of air at current room pressure is 1.1845 g/L, calculate the mass of air his flask before she started. |
g |

5. If his flask was filled with air when he first weighed it, what is the actual mass of the completely empty flask (with no air)? |
g |

6. Taking into account your calculation from Question 5, what is the mass of CO |
g |

7. What is that volume? |
L |

8. Let’s consider the gas that he collected as Condition 1, and STP as Condition 2. (Consider that standard pressure is 1013 mbar.) Using the combined gas laws, and his results, calculate the volume of gas that would have been collected at STP. |
mL |

9. Using your answers from Question 7 and 8, convert the volume of gas collected at STP into moles. |
mol |

10. Using your answers from Questions 6 and 9, calculate the experimental value of the molar mass of CO |
g/mol |

11. What is the actual known value for the molar mass of CO |
g/mol |

12. Calculate percent error using the equation |
% |