- Condensation requires reducing the kinetic energy of gas particles, which is done by decreasing the temperature.
- Increasing the pressure forces gas particles closer together, enabling intermolecular forces to hold them in the liquid state.
- Therefore, a gas turns to a liquid by decreasing the temperature and increasing the pressure.
- The completed statement is: We can change a gas to liquid by \(\boxed{\text{decreasing}}\) the temperature and \(\boxed{\text{increasing}}\) the pressure.
Explanation
- Analyzing the Condensation Process
Condensation is the phase transition from a gas to a liquid. For this transition to occur, gas molecules must lose enough kinetic energy to be held together by intermolecular forces, and they must be brought close enough for these forces to become effective.
- Effect of Temperature: Gas molecules move at high speeds, and their average kinetic energy is directly related to temperature. By decreasing the temperature, the kinetic energy of the molecules decreases, allowing them to slow down and aggregate into a liquid state. Therefore, the temperature must be decreased.
- Effect of Pressure: Increasing the pressure on a gas sample compresses it, forcing the gas molecules closer together. When the molecules are closer, intermolecular attractions become dominant, facilitating the transition into a liquid phase. Therefore, the pressure must be increased.
- Completing the Sentence
Based on the analysis, the process of changing a gas into a liquid is achieved by decreasing the temperature and increasing the pressure. Checking the provided options, 'decreasing' is suitable for the first box, and 'increasing' is suitable for the second box. Thus, the completed sentence is: We can change a gas to liquid by decreasing the temperature and increasing the pressure.
Examples
In industry, this process is essential for storing gases as liquids. For example, propane gas in a backyard grill tank is stored as a liquid by being compressed under high pressure and kept at a manageable temperature. This allows a large amount of fuel to be stored in a relatively small space, making it efficient for transport and daily use. Understanding these phase changes helps engineers design safer storage tanks and efficient refrigeration systems.