2 Matching Annotations
- Jun 2020
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chem.libretexts.org chem.libretexts.org
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Figure 6.1.46.1.4\PageIndex{4}: Temperature versus heat. The system is constructed so that no vapor evaporates while ice warms to become liquid water, and so that, when vaporization occurs, the vapor remains in the system. The long stretches of constant temperatures at 0oC0oC0^oC and 100oC100oC100^oC reflect the large amounts of heat needed to cause melting and vaporization, respectively.
Figure 6.1.4 : Temperature versus heat. The system is constructed so that no vapor evaporates while ice warms to become liquid water, and so that, when vaporization occurs, the vapor remains in the system. The long stretches of constant temperatures at 0oC and 100oC reflect the large amounts of heat needed to cause melting and vaporization, respectively.
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Heat and work have signs (positive or negative), and the sign of each depends on whether the system we are considering is gaining or losing energy. In this class, if a process makes the system gain energy, qqq and/or www are positive; if the process makes the system lose energy, qqq and/or www are negative. We can put this information into four formal statements: If heat flows into a system, qqq is positive. If heat flows out of a system, qqq is negative If the surroundings do work on the system, www is positive. If the system does work, www is negative.
Heat and work have signs (positive or negative), and the sign of each depends on whether the system we are considering is gaining or losing energy. In this class, if a process makes the system gain energy, q and/or w are positive; if the process makes the system lose energy, q and/or w are negative. We can put this information into four formal statements:
- If heat flows into a system, q is positive.
- If heat flows out of a system, q is negative
- If the surroundings do work on the system, w is positive.
- If the system does work, w is negative.
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