I have a couple of questions I need a hand with:
1. Oxygen has a melting point of -218 degrees celcius and a boiling point of -183 degrees celcius. This means that oxygen would be a liquid at...?
Please do not tell me the answer, but tell me the relation between the melting point and boiling point and HOW i can use it to determine when a substance is liquid. Feel free to give me examples.
2. When a substance absorbs heat from its surroundings it could:
A) condense or melt.
B) solidify or condense.
C) evaporate or condense.
D) evaporate or melt.
I'm guessing it is 'evaporate or melt'? Correct me if I am wrong, along with an explanation.
3. When wax melts, the wax particles:
A) change shape to fit the surface they are on.
B) gain energy and spread out alot.
C) become softer.
D) Gain energy and move more freely.
I'm caught between B) and D).. but leaning towards D) more. Again, any explanations would be great!
Thank you very much.
First, note the correct spelling of celsius.
It's tough to draw pictures on the board. Here's about the best I can do for #1, oxygen.
_______25 C room tempeature
oxygen vapor|
............v (I tried to draw an arrow pointing down.)
_______-183 boiling point
liquid
________-218 melting point
solid
Therefore, colder than -218 is solid, between -218 and -183 is liquid, and above -183 is vapor.
I think if you will draw a diagram something like this for the type question you will always know where you are on the temperature scale.
2. When a substance ABSORBS heat, it moves UP (from a referencer point BELOW) so a solid could melt, a liquid could vaporize. Your answer is correct.
3. I don't like any of the answers but your answer is the best listed. There is some truth to A (it does change shape and fits the surface), B(it does gain energy--I don't know about spreading out a lot), C (they do become softer), and D. D is the best overall description and it is general.
Thanks
how much energy would be required to change 24.7g of ice to liquid water?the heat of fusion for water is 6.01 kj/mol?
1. The relation between the melting point and boiling point of a substance can be used to determine its physical state at a given temperature. In the case of oxygen, with a melting point of -218 degrees Celsius and a boiling point of -183 degrees Celsius, we can observe the following:
- When the temperature is below -218 degrees Celsius, oxygen would exist as a solid because it is below its melting point. The particles of oxygen would be arranged in a rigid structure.
- When the temperature is between -218 degrees Celsius and -183 degrees Celsius, oxygen would transition from a solid to a liquid state. This is because the temperature is within the range of its melting point and below its boiling point. At this point, the particles of oxygen would start to gain enough energy to break free from their fixed positions and start moving around more freely, forming a liquid.
- When the temperature exceeds -183 degrees Celsius, oxygen would be in its gaseous state. This is because the temperature is above its boiling point, and the particles of oxygen have gained enough energy to break away completely from the liquid state and move independently as a gas.
To summarize, a substance is in a liquid state when its temperature is above its melting point but below its boiling point. If the substance is below its melting point, it will be in a solid state, and if the temperature exceeds its boiling point, it will exist as a gas.
2. You guessed correctly! When a substance absorbs heat from its surroundings, it can either evaporate or melt. Let's break down the options to understand why:
- Condensation is the process in which a substance changes from a gas to a liquid state. It occurs when heat is removed from the substance.
- Solidification is the process in which a liquid changes into a solid state. It also occurs when heat is removed from the substance.
- Evaporation is the process in which a liquid changes into a gas state by gaining heat from its surroundings.
- Melting is the process in which a solid changes into a liquid state by gaining heat.
In this case, when a substance absorbs heat from its surroundings, the options A) condense or melt and D) evaporate or melt are both incorrect because they suggest that the substance would undergo a phase change from both solid to liquid and liquid to gas simultaneously. Option B) solidify or condense is incorrect because it suggests that the substance would change from a liquid to a solid state, which is not possible when heat is being absorbed.
Therefore, the correct answer is C) evaporate or condense. When a substance absorbs heat, it can either evaporate (change from a liquid to a gas) by gaining energy or condense (change from a gas to a liquid) by losing energy.
3. The correct answer is D) Gain energy and move more freely. When wax melts, the wax particles absorb heat energy from their surroundings. This increase in energy causes the particles to overcome the attractive forces holding them together in a solid state. As a result, the particles gain enough energy to move more freely, allowing the solid wax to transform into a liquid state. So, option D) best describes the behavior of the wax particles when they melt.
Option B) gaining energy and spreading out a lot might describe the behavior of a gas, where individual particles rapidly move and spread out in all directions. However, during the melting of wax, the particles gain energy and become more mobile while still maintaining some level of proximity to each other.
I hope these explanations are helpful! Let me know if you have any further questions.