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. Consider a bulk composition that consists of 80wt%An(X). At what temperature will this mixture begin to melt? At what temperature will first crystals form upon cooling? 2. What will the composition of the first melt be upon heating of X ? Of Y ? What will the first crystals be upon cooling of X ? Of Y ? 3. For bulk composition X at 1350 ∘

, what will the system consist of? Give the phases present, their compositions, and their proportions. 4. Suppose that bulk composition X at 1200 ∘
is warmed up until it begins to melt, and then more heat is added. What happens? Consider two cases: one in which all the melt is retained in the system (equilibrium melting), and the other where melt is extracted from the system as it is formed (fractional melting). 5. For bulk composition X, over what temperature range can melt and crystals coexist? For pure An, what is the range? 6. For bulk composition X, predict what a series of lavas would look like if a magma chamber containing a liquid of bulk composition X erupted lava flows at 1600 ∘
,1400 ∘
, and 1274 ∘
. 7. Formulate 3 or 4 "rules of thumb" for the behavior of binary eutectic systems.

User Zakiyah
by
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1 Answer

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To address your questions regarding a bulk composition consisting of 80wt% An(X), I'll provide answers to each point below:The temperature at which the mixture will begin to melt depends on the specific melting behavior of An(X). Without information about the eutectic or melting points of the components involved, it is not possible to determine the exact temperature.

The composition of the first melt upon heating of X will depend on the specific phase diagram of the system. Similarly, the composition of the first melt upon heating of Y will also depend on the system's characteristics. Without further details, it is not possible to provide specific compositions for the first melts or the first crystals upon cooling of X and Y

For bulk composition X at 1350 °C, the system's constituents will depend on the phase diagram of An(X). It could consist of various phases, such as liquid melt, solid crystals, or even intermediate solid solutions. The proportions of each phase and their compositions will require specific phase diagram information.

When bulk composition X at 1200 °C is warmed up until it begins to melt, two scenarios can be considered:

a) Equilibrium melting: If all the melt is retained in the system during heating, the temperature will continue to rise until reaching a point where the entire mixture has melted. This temperature will depend on the phase diagram of An(X).

b) Fractional melting: If the melt is extracted from the system as it is formed, the temperature will rise until the point where the first melt is removed. The temperature at this point will depend on the composition of the melt and the extraction process. Further heating will continue to melt the remaining solid until reaching the temperature where the entire mixture has melted.

The temperature range at which melt and crystals can coexist for bulk composition X depends on the phase diagram of An(X). It will vary based on the specific eutectic or solidus/liquidus temperatures of the components. Without this information, it is not possible to determine the temperature range.

For pure An, the range where melt and crystals can coexist will also depend on its phase diagram. Typically, a pure component will have a melting temperature range between the solidus and liquidus temperatures.

To predict the appearance of lava flows from a magma chamber containing a liquid of bulk composition X at different temperatures, we need to know the phase diagram and cooling behavior of An(X). This information is necessary to understand the crystallization sequence and the formation of different minerals at different temperatures. Without specific details, it is not possible to describe the lava flows accurately.

Here are three "rules of thumb" for the behavior of binary eutectic systems:

a) The eutectic composition is typically distinct from the compositions of the pure components. It represents the composition at which the lowest melting temperature occurs, resulting in a eutectic mixture.

b) During cooling, the first crystals to form will have the composition of the eutectic. These crystals will continue to grow until the eutectic temperature is reached.

c) Thee eutectic temperatur is generally lower than the melting points of the individual components, allowing for the formation of a eutectic mixture that is different from the pure components.

Please note that without specific phase diagram data or information about the specific components involved, the answers provided are general and cannot account for the specific behavior of An(X) in your case.

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User Saurabh Prajapati
by
8.4k points
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