Question

q1 chemistry. u1l7 unit 1 review
prepwork: u1 review

1. *carbon dioxide has a formula of co₂. use this knowledge to represent phase changes from solid to liquid to gas of a sample of carbon dioxide. label each phase and create a key showing an atom of co₂.
2. *nitrogen (n₂) is in the liquid state at an extremely cold temperature. it boils at -195.79°c (-320°f) and freezes at -210 °c (-346 °f). liquid nitrogen is typically contained in vacuum flasks, called dewars, which allows the nitrogen to remain cooler than its surroundings. once released to atmospheric conditions, liquid nitrogen boils and is released as a gas, but can cause rapid solidification on contact with living tissue.

in the space provided, draw a particle diagram to represent given scenarios. your response must include at least four molecules in each phase.
the dewar shown above is kept in an industrial freezer in the lab. the temperature of the freezer averages - 201°c.
show the two phases of nitrogen that exist when the rubber stopper is taken off of the dewar. the temperature in the lab is around 23°c.

Explanation:

Step1: Represent carbon - dioxide phases

For carbon - dioxide:

• Solid phase: Draw closely - packed $CO_2$ molecules in a regular pattern to represent dry ice.
• Liquid phase: Draw $CO_2$ molecules a bit more spread out than in the solid phase but still somewhat close together.
• Gas phase: Draw $CO_2$ molecules far apart from each other, moving freely.

Step2: Draw nitrogen particle diagrams

• Liquid nitrogen in Dewar (-201°C): Draw four or more $N_2$ molecules close together but able to slide past each other within the Dewar.
• Liquid and gas nitrogen when stopper is removed: On one side of the diagram, draw four or more $N_2$ molecules in the liquid phase (close - packed but mobile). On the other side, draw four or more $N_2$ molecules in the gas phase (very spread out and moving freely).

Answer:

Diagrams should be drawn as described above for carbon - dioxide and nitrogen phases with appropriate molecule arrangements and labels for each phase.