Question

Assignment

You shall write a program that:

Loads chemical-element data by scanning through the file (accessed via file path or URL) exactly once.

Expects one or more command-line arguments that constitute a chemical formula, as described above.

Prints one line containing the molar mass of the compound described by the formula, to six digits after the decimal point.

Background

Data file

There is a file on the server that is relevant to this assignment:

/srv/datasets/elements

This file contains one line of information about each of all 118 chemical elements. Each line contains the following data, separated by whitespace:

Atomic number (int)

Symbol (String)

Name (String)

Relative atomic mass (double)

Period (row in periodic table) (int)

Group (column in periodic table) (int)

FYI, this file is also available via URL http://jeff.cis.cabrillo.edu/datasets/elements

Chemical Formulas

Quoth the arbiter of all human knowledge:

A chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and plus (+) and minus (−) signs.

Often, these formulas are written using subscripts and superscripts. In this program, we will simplify the idea of a chemical formula (and thus sacrifice the ability to represent certain formulas, at least in an efficient way). A chemical formula, for the sake of this program, shall be defined as:

One or more whitespace-delimited tokens

Each token consists of either:

An element symbol, implying one atom of that element in the compound

An element symbol followed by an underscore and an integer, implying a certain number of atoms of that element in the compound

Examples:

CompoundStandard FormulaOur FormulacarbonCCdioxygenO₂O_2dialuminum tellurideAl₂TeAl_2 Telithium metazirconateLi₂ZrO₃Li_2 Zr O_3acetaldehydeCH₃CHOC H_3 C H OmethylamineCH₅NC H_5 NparacetamolC₈H₉NO₂C_8 H_9 N O_2propaneC₃H₈C_3 H_8

Molar Mass

Molar mass expresses the mass of a given substance (chemical element or chemical compound) divided by its amount of substance. The molar mass of a compound is the sum of the relative atomic masses (AKA atomic weights) of all atoms in the compound.

For example, for acetaldehyde (CH₃CHO/C H_3 C H O) above:

Relative atomic masses:

C: 12.011

H: 1.008

O: 15.999

Thus, the compound's molar mass is:12.011+3(1.008)+12.011+1.008+15.999=44.05312.011+3(1.008)+12.011+1.008+15.999=44.053

Technically, the units for molar mass are gmolgmol in this case.

Helpful String and parsing methods

In order to separate the element name from the number of atoms, there are a number of methods in the String class that you may find useful. Probably the most straightforward is String.split, with which you can create an array of Strings by splitting one string around a pattern of characters.

In addition, Integer.parseInt will certainly be useful, as it returns the int value represented by the characters in a String.

For example:

String compound = "O_2"; String[] components = compound.split("_"); // Value assigned is a reference to a two-element array: { "O", "2" } String element = components[0]; // Value assigned is a reference to a string containing "O" int atoms = Integer.parseInt(components[1]); // Value assigned is 2

Also, don't forget that if you want to determine whether two Strings contain the same sequence of characters:

oneString == anotherString // Do oneString and anotherString refer to the same String object? oneString.equals(anotherString) // Do oneString and anotherString contain the same character sequences?

Command-line arguments in Eclipse

In order to work with command-line arguments from within Eclipse, you need to specify those arguments within either Run Configurations or Debug Configurations, depending on whether you want to run or debug the program.

Select Run–>Run Configurations or Run–>Debug Configurations as desired.

Select the Arguments tab.

In the Program Arguments section , Enter your arguments.

Click Apply.

this is the contacts of file needed

1 H Hydrogen 1.008 1 1 2 He Helium 4.002602 1 18 3 Li Lithium 6.94 2 1 4 Be Beryllium 9.0121831 2 2 5 B Boron 10.81 2 13 6 C Carbon 12.011 2 14 7 N Nitrogen 14.007 2 15 8 O Oxygen 15.999 2 16 9 F Fluorine 18.998403163 2 17 10 Ne Neon 20.1797 2 18 11 Na Sodium 22.98976928 3 1 12 Mg Magnesium 24.305 3 2 13 Al Aluminium 26.9815385 3 13 14 Si Silicon 28.085 3 14 15 P Phosphorus 30.973761998 3 15 16 S Sulfur 32.06 3 16 17 Cl Chlorine 35.45 3 17 18 Ar Argon 39.948 3 18 19 K Potassium 39.0983 4 1 20 Ca Calcium 40.078 4 2 21 Sc Scandium 44.955908 4 3 22 Ti Titanium 47.867 4 4 23 V Vanadium 50.9415 4 5 24 Cr Chromium 51.9961 4 6 25 Mn Manganese 54.938044 4 7 26 Fe Iron 55.845 4 8 27 Co Cobalt 58.933194 4 9 28 Ni Nickel 58.6934 4 10 29 Cu Copper 63.546 4 11 30 Zn Zinc 65.38 4 12 31 Ga Gallium 69.723 4 13 32 Ge Germanium 72.63 4 14 33 As Arsenic 74.921595 4 15 34 Se Selenium 78.971 4 16 35 Br Bromine 79.904 4 17 36 Kr Krypton 83.798 4 18 37 Rb Rubidium 85.4678 5 1 38 Sr Strontium 87.62 5 2 39 Y Yttrium 88.90584 5 3 40 Zr Zirconium 91.224 5 4 41 Nb Niobium 92.90637 5 5 42 Mo Molybdenum 95.95 5 6 43 Tc Technetium 98 5 7 44 Ru Ruthenium 101.07 5 8 45 Rh Rhodium 102.9055 5 9 46 Pd Palladium 106.42 5 10 47 Ag Silver 107.8682 5 11 48 Cd Cadmium 112.414 5 12 49 In Indium 114.818 5 13 50 Sn Tin 118.71 5 14 51 Sb Antimony 121.76 5 15 52 Te Tellurium 127.6 5 16 53 I Iodine 126.90447 5 17 54 Xe Xenon 131.293 5 18 55 Cs Caesium 132.90545196 6 1 56 Ba Barium 137.327 6 2 57 La Lanthanum 138.90547 6 0 58 Ce Cerium 140.116 6 0 59 Pr Praseodymium 140.90766 6 0 60 Nd Neodymium 144.242 6 0 61 Pm Promethium 145 6 0 62 Sm Samarium 150.36 6 0 63 Eu Europium 151.964 6 0 64 Gd Gadolinium 157.25 6 0 65 Tb Terbium 158.92535 6 0 66 Dy Dysprosium 162.5 6 0 67 Ho Holmium 164.93033 6 0 68 Er Erbium 167.259 6 0 69 Tm Thulium 168.93422 6 0 70 Yb Ytterbium 173.045 6 0 71 Lu Lutetium 174.9668 6 3 72 Hf Hafnium 178.49 6 4 73 Ta Tantalum 180.94788 6 5 74 W Tungsten 183.84 6 6 75 Re Rhenium 186.207 6 7 76 Os Osmium 190.23 6 8 77 Ir Iridium 192.217 6 9 78 Pt Platinum 195.084 6 10 79 Au Gold 196.966569 6 11 80 Hg Mercury 200.592 6 12 81 Tl Thallium 204.38 6 13 82 Pb Lead 207.2 6 14 83 Bi Bismuth 208.9804 6 15 84 Po Polonium 209 6 16 85 At Astatine 210 6 17 86 Rn Radon 222 6 18 87 Fr Francium 223 7 1 88 Ra Radium 226 7 2 89 Ac Actinium 227 7 0 90 Th Thorium 232.0377 7 0 91 Pa Protactinium 231.03588 7 0 92 U Uranium 238.02891 7 0 93 Np Neptunium 237 7 0 94 Pu Plutonium 244 7 0 95 Am Americium 243 7 0 96 Cm Curium 247 7 0 97 Bk Berkelium 247 7 0 98 Cf Californium 251 7 0 99 Es Einsteinium 252 7 0 100 Fm Fermium 257 7 0 101 Md Mendelevium 258 7 0 102 No Nobelium 259 7 0 103 Lr Lawrencium 266 7 3 104 Rf Rutherfordium 267 7 4 105 Db Dubnium 268 7 5 106 Sg Seaborgium 269 7 6 107 Bh Bohrium 270 7 7 108 Hs Hassium 269 7 8 109 Mt Meitnerium 278 7 9 110 Ds Darmstadtium 281 7 10 111 Rg Roentgenium 282 7 11 112 Cn Copernicium 285 7 12 113 Nh Nihonium 286 7 13 114 Fl Flerovium 289 7 14 115 Mc Moscovium 290 7 15 116 Lv Livermorium 293 7 16 117 Ts Tennessine 294 7 17 118 Og Oganesson 294 7 18

Answer 1