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What steps can you take to determine the melting point of a substance that sublimes before it melts?
Wiki User
∙ 13y ago
In such cases the melting point determination must be performed in a sealed capillary tube to avoid loss of sample. This can be achieved by heating the open end of the capillary tube, and with tweezers forcing it shut.
Wiki User
∙ 13y ago
- Use a sealed capillary tube to prevent the substance from subliming during the heating process.
- Gradually heat the substance until you observe both sublimation and melting.
- Record the temperature range at which both sublimation and melting occur as the melting point.
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How do you determine melting point of a compound that sublimes or decomposes before melting?
For compounds that sublimate or decompose before melting, a sublimation point or decomposition temperature can be determined instead of a melting point. This can be done by heating the compound and observing at what temperature it starts to sublimate or decompose. Various techniques like differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) can be used to analyze these temperature changes.
How long from the from the start of the experiment was the substance heated before all of the substance turned into a liquid?
The substance was heated until it reached its melting point, which led to its transformation into a liquid state. The duration of heating required to achieve this phase change depends on the specific substance being heated and its melting point.
Why is the melting point of a substance is a physical property but flammability is a chemical property?
The melting point of a substance is a physical property because it is determined by the arrangement and movement of the molecules within the substance. On the other hand, flammability is a chemical property because it describes how a substance reacts chemically with oxygen in the presence of heat to produce combustion.
What is the melting point in degrees Celsius?
Each substance has a different melting point. That depends on what compound you're talking about: Of table salt, NaCl, it is 801 °C though of water (ice), H2O, it is 0 °C and of carbon dioxide it is even lower: -78 °C
Why is a filter paper is a poor material to powder a solid before introducing it into a melting tube?
Filter paper is a poor material for powdering a solid before introducing it into a melting tube because it is not abrasive enough to effectively break down the solid into a fine powder. The pores of the filter paper may also retain some of the solid, reducing the amount of substance that can be transferred to the melting tube. Additionally, the filter paper itself may contaminate the solid material being powdered.
How do you determine melting point of a compound that sublimes or decomposes before melting?
For compounds that sublimate or decompose before melting, a sublimation point or decomposition temperature can be determined instead of a melting point. This can be done by heating the compound and observing at what temperature it starts to sublimate or decompose. Various techniques like differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) can be used to analyze these temperature changes.
How can a substance have no melting point or boiling point?
Example: compounds that are thermally decomposed before a supposed melting or boiling point.
What is the significance of boiling point and melting point of a substance?
Melting points and boiling points are phyical constants which means specific compounds have specific melting/boiling points. Therefore you can identify a substance if you determine the mp/bp. Also you measure the purity of a mixture using melting point tests.
Why the melting point of a substance is a physical property but flammability is a chemical property?
When a substance melts, it changes state from solid to liquid. This does not alter the substance's chemical composition, so melting point is a physical property. Flammability means burning, and when a substance burns, it reacts with oxygen to produce a new substance that was not there before. This is therefore a chemical property.
What happens if a pure substance is exactly at its melting point?
it "sweats" almost like melting plastic on a Bunsen burner, like how small droplets form just before the whole pen melts.
How do the melting point and the freezing point of a substance compare?
Both indicate the temperature at which the solid and liquid states of a substance are in equilibrium.
What happens to the temperature of naphthalene during melting?
Lab: Melting / Freezing Point of NaphthaleneObjective: In this lab, you will investigate the melting and freezing point of the substance, naphthalene (moth ball flakes). You will heat solid naphthalene and record temperature changes and examine the graph to determine the melting point of the substance. You will then cool naphthalene and record temperature changes in order to determine the Freezing point of the substance Part A: What happens to temperature as naphthalene melts?Objective: As heat is applied to liquid naphthalene, the temperature rises. As the temperature rises, the naphthalene will eventually start to melt. This lab experiment tries to answer the question: what happens to the temperature of naphthalene as it melts? In this lab, you will heat the liquid naphthalene, and record the temperature changes. You will graph the temperature changes before drawing any conclusions.Part B: Determining the freezing point of naphthaleneObjective: Freezing point is a characteristic property of matter. As heat is taken away from a liquid, the temperature of that liquid decreases as the substance begins to freeze. This lab experiment tries to answer the question: what is the freezing point of an unknown liquid (naphthalene)? In this lab, you will cool liquid naphthalene, and record the temperature changes. You will graph the temperature changes before drawing any conclusions.
Why is the melting point of a substance is a physical property but flammability is a chemical property?
The melting point of a substance is a physical property because it is determined by the arrangement and movement of the molecules within the substance. On the other hand, flammability is a chemical property because it describes how a substance reacts chemically with oxygen in the presence of heat to produce combustion.
What type of chage is melting ice?
Melting ice involves a physical change, as it transitions from a solid state to a liquid state while maintaining the same chemical composition. The process does not alter the molecular structure of the ice, making it reversible.
What is the temperature of a substance does not change before the?
The Phase Change is complete, e.g water melting from ice phase to liquid phase or water evaporating from liquid to gas. Save
How long from the from the start of the experiment was the substance heated before all of the substance turned into a liquid?
The substance was heated until it reached its melting point, which led to its transformation into a liquid state. The duration of heating required to achieve this phase change depends on the specific substance being heated and its melting point.
If a substace is a liquid already what would it be before the melting point?
It would be solid before it reached the melting point. If it is liquid, it has already reached the melting point.
