Aug
2
what determines the physical state of a substance at room tempurature?
Filed Under Physical Chemistry
it is a chemistry hw assignment.
By: lotyr14
By: lotyr14
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5 Responses to “what determines the physical state of a substance at room tempurature?”
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Its force of cohersion, that force is affected by the temperarature in the ambience. And its about the kind of structure of the matter itself.
The pressure that the substance is under. At room temperature for example, water can be ice, liquid, or steam, depending on the pressure of the room or container.
First of all, you misspelled temperature. Secondly, you should stop being so lazy and look up the answer in your text book. It’s an entry-level chemistry question!!! But I’ll give you the benefit of doubt and pretend you tried in vain to research the answer… The physical state of matter is self explanatory. Is the substance a solid, liquid or gas? We can rule out that it won’t be plasma. Chemical/ molecular structure is, ultimately, what determines a substance’s physical state, or any other property, for that matter… I weep for our country’s future, lol…
THere are several factors determining the physical state.
1. The substance itself - each different substance has different transition stages whether it is a molecule (water), element (iron), alloy (steel), or mixture (cordial).
2. Temperature - This is a measurement of the energy of the substance, add energy to the system and the temperature will rise (generally speaking). When it reaches certain points the substance will undergo change that takes more energy to occur.
3. Volume - Substances take up different amounts of space when in different states. Generally speaking liquid takes more space than solids, gases take more than both. Water/ice is one exception (ie takes more space than water). If the system is small area then pressure will increase with increse temperature and phase changes may be limited. (water is unlikely to change to gas if little space, but will do so at low tempurature if there is a vacuum).
4. Pressure - already mentioned above, pressure is dependant on the space available and the tempurature of the system.
Interesting effects:
A small ice block will vapourise to gas in 20L of Vacuum, even though it is still freezing.
Water boils at lower tempuratures at higher altitudes, so a pot of coffee at mount everest may look hot, but is not.
Adding salt to water will change the substance so it will have a higher boiling point.
The short answer is: 1) molecular mass and 2) the kind and strength of the intermolecular forces - hydrogen bonding, dipole-dipole interactions, London dispersion forces, etc.