document.write( "Question 1005270: Solution XRD is one half sulfur acid while QXJ is 3/4 sulfur acid. How many liters of solution QXJ should be added to a liter of solution XRD to obtain a solution that is 3/5 sulfur acid? \n" ); document.write( "
Algebra.Com's Answer #621697 by KMST(5328)\"\" \"About 
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WHAT A MATH TEACHER THINKS:
\n" ); document.write( "The volume of a mix of two liquids is the sum of the volumes mixed together.
\n" ); document.write( "\"Amount=Volume%2AConcentration\"
\n" ); document.write( "No need to specify concentration/amount units, because they are self-explanatory.
\n" ); document.write( "So the math teacher would add \"highlight%282%2F3%29=about+0.667\" Liters of solution QXJ to 1 Liter solution XRD and mix, expecting to get \"about1.667L\" of solution with a 0.6 concentration.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "WHAT A SCIENTIST THINKS:
\n" ); document.write( "Chemists know that it is important to specify your units.
\n" ); document.write( "When a chemist says a solution is 50% sulfuric acid,
\n" ); document.write( "they usually mean it contains 50 kg sulfuric acid per 100 kg solution.
\n" ); document.write( "If they want to be clearer, they say it is 50%(w/w).
\n" ); document.write( "Biologists tend to describe how the solutions were prepared.
\n" ); document.write( "When you mix together two substances, the mass of the mixture is the sum of the masses of the components.
\n" ); document.write( "The same is not true about volumes.
\n" ); document.write( "Scientists know that, and so do construction workers.
\n" ); document.write( "Any construction worker knows that mixing 1 cubic yard of rocks and 1 cubic yard of fine sand does not yield 2 cubic yards of mixture.
\n" ); document.write( "A chemist knows that mixing \"1\" Liter of a solution with \"x\" Liters of another solution yields a volume usually close to \"1%2Bx\" Liters, but not exactly \"1%2Bx\", and sometimes quite far from exactly that.
\n" ); document.write( "A synthetic chemist and a biologist shrug and say it is probably close enough for their purposes.
\n" ); document.write( "An analytical chemist says that will make my analysis results very wrong.\r
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\n" ); document.write( "\n" ); document.write( "IF A BIOLOGIST IS INVOLVED:
\n" ); document.write( "The way the concentrations of those solutions are described,
\n" ); document.write( "maybe those solutions are usually prepared by a biologist,
\n" ); document.write( "who mixes water and concentrated sulfuric acid to make solutions as follows:
\n" ); document.write( "Solution XRD \"half sulfuric acid\" = 1L water + 1L concentrated sulfuric acid;
\n" ); document.write( "Solution QXJ \"3/4 sulfur acid\" = 1L water + 3L concentrated sulfuric acid.
\n" ); document.write( "Maybe that biologist wanted to make more of
\n" ); document.write( "Solution UVW \"3/5 sulfuric acid\" = 2L water + 3L concentrated sulfuric acid.
\n" ); document.write( "The biologist most likely had a bottle of \"concentrated sulfuric acid\" that contained 98g of sulfuric acid per 100g of liquid.
\n" ); document.write( "The label may have stated \"Assay....98.0%, meaning that its concentration was 98.0%(w/w).
\n" ); document.write( "Data in a handbook says that at \"20%5Eo\"\"C\" the density of that solution is \"1.8361\"\"%22kg+%2F+L%22\" .
\n" ); document.write( "
\n" ); document.write( "Solution XRD, with \"1.0000L=1.0000kg\" water and \"1.0000L=1.8361kg\" concentrated acid, had a total mass of about
\n" ); document.write( "\"1.0000kg%2B1.8361kg=2.8361kg\" , and
\n" ); document.write( "a total amount of pure acid of about \"0.98%2A1.8361kg=1.7994kg\" .
\n" ); document.write( "(I say \"about\" because a biologist does not measure \"1L\" volumes with anything near a precision of \"0.0001L\" ).
\n" ); document.write( "The calculated acid concentration is \"0.98%2A1.8361kg%2F%222.8361+kg%22=0.634=%2263.4+%25+%7B+w+%2F+w+%29%22\" .
\n" ); document.write( "The handbook says that the density of that solution is \"1.5354\"\"%22kg+%2F+L%22\" at \"20%5EoC\"\"C\" ,
\n" ); document.write( "so the concentration is \"kg+acid%2F%22L+solution%22\" .
\n" ); document.write( "
\n" ); document.write( "Solution QXJ, with \"1.0000L=1.0000kg\" water and \"3.0000L=3%2A1.8361kg=5.5083kg\" concentrated acid, had a total mass of about
\n" ); document.write( "\"1.0000kg%2B5.5083kg=6.5083kg\" , and
\n" ); document.write( "about \"0.98%2A5.5083kg=5.3981kg\" of pure acid.
\n" ); document.write( "The calculated acid concentration is \"5.3981kgacid%2F%226.5083+kgsolution%22=0.829=82.9%25\" .
\n" ); document.write( "The handbook says that the density of that solution is \"1.5354\"\"%22kg+%2F+L%22\" at \"20%5Eo\"\"C\" ,
\n" ); document.write( "so the concentration is \"kg+acid%2F%22L+solution%22\" .
\n" ); document.write( "Solution, with \"2.0000L=2.0000kg\" water and
\n" ); document.write( "\"3.0000L=3%2A1.8361kg=5.5083kg\" concentrated acid, had a total mass of about
\n" ); document.write( "\"2.0000kg%2B5.5083kg=7.5083kg\" , and
\n" ); document.write( "about \"0.98%2A5.5083kg=5.3981kg\" of pure acid.
\n" ); document.write( "The calculated acid concentration is \"5.3981kgacid%2F%227.5083+kgsolution%22=0.719=71.9%25\" .
\n" ); document.write( "The handbook says that the density of that solution is \"1.6326\"\"%22kg+%2F+L%22\" at \"20%5Eo\" ,
\n" ); document.write( "so the concentration is \"%280.7190kgacid%2F%221+kg++solution%22%29%281.6326kgsolution%2F%221+Lsolution%22%29=1.1738\"\"kg+acid%2F%22L+solution%22\" .
\n" ); document.write( "
\n" ); document.write( "Mixing \"i.0000L=1.5354kg\" of solution XRD,
\n" ); document.write( "containing \"0.9741kg\" pure acid and
\n" ); document.write( "\"2%2F3\"\"L=%282%2F3%29%281.7584kg%29=1.1723kg\" of Solution QXJ,
\n" ); document.write( "containing \"%282%2F3%29%281.4585kg%29=0.9723kg\" pure acid, the biologist gets
\n" ); document.write( "a total of \"0.9741kg%2B0.9723kg=1.9464kg\" pure acid in
\n" ); document.write( "a total of \"1.5354kg%2B1.1723kg=2.7077kg\" of solution.
\n" ); document.write( "The concentration is \"1.9464%2F2.7077=0.7188\" in kg pure acid/kg solution,
\n" ); document.write( "which still rounds to \"71.9%25\" , close enough for the biologist.
\n" ); document.write( "The final volume of solution obtained is
\n" ); document.write( "\"2.7077kgsolution%281Lsolution%2F1.6326kgsolution%29=1.659L\" , also close enough for the biologist.
\n" ); document.write( "
\n" ); document.write( "IF A CHEMIST WAS DESCRIBING THOSE SOLUTIONS:
\n" ); document.write( "When a chemist says a solution is 50% sulfuric acid,
\n" ); document.write( "they usually mean it contains 50 kg sulfuric acid per 100 kg solution.
\n" ); document.write( "If they want to be clearer, they say it is 50%(w/w).
\n" ); document.write( "That is a pretty dense solution;
\n" ); document.write( "At \"20%5EoC\" , \"1\" Liter has a mass of \"1.3951\" kg.
\n" ); document.write( "When someone says a solution is 60% sulfuric acid,
\n" ); document.write( "they usually mean it contains 60 kg sulfuric acid per 100 kg solution.
\n" ); document.write( "If they want to be clearer, they say it is 60%(w/w).
\n" ); document.write( "That is a denser solution.
\n" ); document.write( "At \"20%5EoC\" , \"1\" Liter has a mass of \"1.4983\" kg.
\n" ); document.write( "When someone says a solution is 75% sulfuric acid,
\n" ); document.write( "they usually mean it contains 75 kg sulfuric acid per 100 kg solution.
\n" ); document.write( "If they want to be clearer, they say it is 75%(w/w).
\n" ); document.write( "That is an even denser solution.
\n" ); document.write( "At \"20%5EoC\" , \"1\" Liter has a mass of \"1.6692\" kg.
\n" ); document.write( "If at \"20%5EoC\" you measure \"1\" Liter of 50% sulfuric acid solution,
\n" ); document.write( "with a total mass of \"1.3951kg\" , containing \"0.5%281.3951kg%29=0.0.6976kg\" sulfuric acid, and
\n" ); document.write( "\"2%2F3\" Liter of 75% sulfuric solution with a mass of \"%282%2F3%291.6692kg=1.1128kg\" , containing \"0.75%281.1128kg%29=0.8346kg\" sulfuric acid, you get
\n" ); document.write( "a total mass of \"1.3951kg%2B1.1128kg=2.5079kg\" of solution containing
\n" ); document.write( "\"0.6976kg%2B0.8346kg=1.5322kg\" of sulfuric acid.
\n" ); document.write( "The concentration of the resulting solution is
\n" ); document.write( "\"1.5322kg%2F%222.5079+kg%22=0.611%28rounded%29=%2261.1%25%28rounded%29%22\" .
\n" ); document.write( "Looking in a handbook, we find that a solution with that final concentration will have a density of \"1.5102\"\"%22kg+%2F+L%22\" .
\n" ); document.write( "So, the \"2.5079kg\" of final solution will have a volume of
\n" ); document.write( "\"%282.5079kg%29%2A%281L%2F%221.5102+kg%22%29=1.661L%28rounded%29\" .
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