What does x mean in (1-x)A – xB composite materials, molar ratio, weight ratio or volume fraction?
$begingroup$
I've been collecting data about ceramic materials and often I get to see composite materials are described as $(1-x)ce{A} - xce{B}$. I am confused what this $x$ means. And I haven't seen any of the papers mention what $x$ is unless %wt is given specifically.
For an example in $(1-x)ce{MgO} - xce{LiF}$ ceramic material, does $x$ mean molar ratio or weight ratio? For me it doesn't make sense to think of $x$ as a volume fraction as most of the times powders of these materials are taken for sintering.
If nothing is mentioned, is it all right to assume $x$ as the molar ratio?
Can we assume volume fraction is equal to molar ratio even in solids or liquids?
physical-chemistry concentration solid-state-chemistry notation
edited 12 hours ago
andselisk
16.2k651114
asked 12 hours ago
avinavin
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I've been collecting data about ceramic materials and often I get to see composite materials are described as $(1-x)ce{A} - xce{B}$. I am confused what this $x$ means. And I haven't seen any of the papers mention what $x$ is unless %wt is given specifically.
For an example in $(1-x)ce{MgO} - xce{LiF}$ ceramic material, does $x$ mean molar ratio or weight ratio? For me it doesn't make sense to think of $x$ as a volume fraction as most of the times powders of these materials are taken for sintering.
If nothing is mentioned, is it all right to assume $x$ as the molar ratio?
Can we assume volume fraction is equal to molar ratio even in solids or liquids?
physical-chemistry concentration solid-state-chemistry notation
edited 12 hours ago
andselisk
16.2k651114
asked 12 hours ago
avinavin
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I've been collecting data about ceramic materials and often I get to see composite materials are described as $(1-x)ce{A} - xce{B}$. I am confused what this $x$ means. And I haven't seen any of the papers mention what $x$ is unless %wt is given specifically.
For an example in $(1-x)ce{MgO} - xce{LiF}$ ceramic material, does $x$ mean molar ratio or weight ratio? For me it doesn't make sense to think of $x$ as a volume fraction as most of the times powders of these materials are taken for sintering.
If nothing is mentioned, is it all right to assume $x$ as the molar ratio?
Can we assume volume fraction is equal to molar ratio even in solids or liquids?
physical-chemistry concentration solid-state-chemistry notation
edited 12 hours ago
andselisk
16.2k651114
asked 12 hours ago
avinavin
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I've been collecting data about ceramic materials and often I get to see composite materials are described as $(1-x)ce{A} - xce{B}$. I am confused what this $x$ means. And I haven't seen any of the papers mention what $x$ is unless %wt is given specifically.
For an example in $(1-x)ce{MgO} - xce{LiF}$ ceramic material, does $x$ mean molar ratio or weight ratio? For me it doesn't make sense to think of $x$ as a volume fraction as most of the times powders of these materials are taken for sintering.
If nothing is mentioned, is it all right to assume $x$ as the molar ratio?
Can we assume volume fraction is equal to molar ratio even in solids or liquids?
physical-chemistry concentration solid-state-chemistry notation
physical-chemistry concentration solid-state-chemistry notation
edited 12 hours ago
andselisk
16.2k651114
asked 12 hours ago
avinavin
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 12 hours ago
andselisk
16.2k651114
asked 12 hours ago
avinavin
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 12 hours ago
andselisk
16.2k651114
edited 12 hours ago
andselisk
16.2k651114
edited 12 hours ago
andselisk
16.2k651114
16.2k651114
asked 12 hours ago
avinavin
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 12 hours ago
avinavin
182
asked 12 hours ago
avinavin
182
182
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
avin is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Here, $x$ is a variable $(xin[0;1])$ denoting mole fraction of a given constituent in a phase of variable composition (non-stoichiometric compound).
This is an algebraic way of denoting a given compound from the phase diagram for a solid solution: $x$ corresponds to its abscissa axis.
And no, volume fraction is not equal to mole fraction and is overall a very inconvenient variable to use, so it's usually being avoided.
For example, volume fraction would deviate for the different morphologies and allotropes of the same solid, which is not useful for the description of chemical composition, not to mention it's also temperature-dependent.
answered 12 hours ago
andseliskandselisk
16.2k651114
$endgroup$
1
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
2
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
add a comment |
Your Answer
StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");
StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "431"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);
StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});
function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});
}
});
avin is a new contributor. Be nice, and check out our Code of Conduct.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fchemistry.stackexchange.com%2fquestions%2f109422%2fwhat-does-x-mean-in-1-xa-xb-composite-materials-molar-ratio-weight-ratio-o%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Here, $x$ is a variable $(xin[0;1])$ denoting mole fraction of a given constituent in a phase of variable composition (non-stoichiometric compound).
This is an algebraic way of denoting a given compound from the phase diagram for a solid solution: $x$ corresponds to its abscissa axis.
And no, volume fraction is not equal to mole fraction and is overall a very inconvenient variable to use, so it's usually being avoided.
For example, volume fraction would deviate for the different morphologies and allotropes of the same solid, which is not useful for the description of chemical composition, not to mention it's also temperature-dependent.
answered 12 hours ago
andseliskandselisk
16.2k651114
$endgroup$
1
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
2
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
add a comment |
$begingroup$
Here, $x$ is a variable $(xin[0;1])$ denoting mole fraction of a given constituent in a phase of variable composition (non-stoichiometric compound).
This is an algebraic way of denoting a given compound from the phase diagram for a solid solution: $x$ corresponds to its abscissa axis.
And no, volume fraction is not equal to mole fraction and is overall a very inconvenient variable to use, so it's usually being avoided.
For example, volume fraction would deviate for the different morphologies and allotropes of the same solid, which is not useful for the description of chemical composition, not to mention it's also temperature-dependent.
answered 12 hours ago
andseliskandselisk
16.2k651114
$endgroup$
1
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
2
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
add a comment |
$begingroup$
Here, $x$ is a variable $(xin[0;1])$ denoting mole fraction of a given constituent in a phase of variable composition (non-stoichiometric compound).
This is an algebraic way of denoting a given compound from the phase diagram for a solid solution: $x$ corresponds to its abscissa axis.
And no, volume fraction is not equal to mole fraction and is overall a very inconvenient variable to use, so it's usually being avoided.
For example, volume fraction would deviate for the different morphologies and allotropes of the same solid, which is not useful for the description of chemical composition, not to mention it's also temperature-dependent.
answered 12 hours ago
andseliskandselisk
16.2k651114
$endgroup$
Here, $x$ is a variable $(xin[0;1])$ denoting mole fraction of a given constituent in a phase of variable composition (non-stoichiometric compound).
This is an algebraic way of denoting a given compound from the phase diagram for a solid solution: $x$ corresponds to its abscissa axis.
And no, volume fraction is not equal to mole fraction and is overall a very inconvenient variable to use, so it's usually being avoided.
For example, volume fraction would deviate for the different morphologies and allotropes of the same solid, which is not useful for the description of chemical composition, not to mention it's also temperature-dependent.
answered 12 hours ago
andseliskandselisk
16.2k651114
edited 12 hours ago
answered 12 hours ago
andseliskandselisk
16.2k651114
answered 12 hours ago
andseliskandselisk
16.2k651114
answered 12 hours ago
andseliskandselisk
16.2k651114
16.2k651114
1
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
2
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
add a comment |
1
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
2
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
1
1
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
Since the OP refers to sintering I don't think that mole fraction can be assumed. In fact the OP mentions that some articles explicitly specify wt %.
$endgroup$
– MaxW
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW Mole fraction is pretty much a default in the absence of additional remarks. Of course, if there is %wt notation, then it's mass fraction.
$endgroup$
– andselisk
12 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
$begingroup$
@MaxW I believe almost all the ceramic compounds are made by sintering. Do you believe 0.8MgO - 0.2LiF could mean weight fractions? Most of the related papers don't mention what x is, although when they do mention about 'weights', they make sure to present it as a percentage, like MgO - 20% LiF. But I'm sure there should be some convention among scientists to understand what x really is unless explicitly specified?
$endgroup$
– avin
11 hours ago
2
2
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
$begingroup$
@avin Again, unless there are any specific notes, $(1-x)ce{MgO} - xce{LiF} ≡ ce{Li_xMg_{(1-x)}O_{(1-x)}F_x}$, so by default $x$ implicates mole fraction.
$endgroup$
– andselisk
11 hours ago
add a comment |
avin is a new contributor. Be nice, and check out our Code of Conduct.
avin is a new contributor. Be nice, and check out our Code of Conduct.
avin is a new contributor. Be nice, and check out our Code of Conduct.
avin is a new contributor. Be nice, and check out our Code of Conduct.
Thanks for contributing an answer to Chemistry Stack Exchange!
- Please be sure to answer the question. Provide details and share your research!
But avoid …
- Asking for help, clarification, or responding to other answers.
- Making statements based on opinion; back them up with references or personal experience.
Use MathJax to format equations. MathJax reference.
To learn more, see our tips on writing great answers.
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fchemistry.stackexchange.com%2fquestions%2f109422%2fwhat-does-x-mean-in-1-xa-xb-composite-materials-molar-ratio-weight-ratio-o%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
