#!/usr/bin/perl 
use warnings; 
use utf8; 
use bignum; 
#using a hash to set up coefficients for each dimension 
my %units = ( 
	nmoles => "1e-9", 
	nL => "1e-9", 
	nM => "1e-9", 
	micromoles => "1e-6", #cant use µmoles as this breaks perl 
	microL => "1e-6", 
	microM => "1e-6", 
	mmoles => "1e-3", 
	mL => "1e-3", 
	mM => "1e-3", 
	moles => "1e0", 
	L => "1e0", 
	M => "1e0" 
 
); 
 
print "what would you like to work out? Moles (1), Volume (2) or Molarity (3)?\n"; 
$input = <STDIN>; 
 
 
if ($input == 1) { 
	print "working out the number of Moles...\n"; 
	print "what is the Molarity?\n"; 
	$molarty = <STDIN>; 
	($molarity, $units1) = split(/ /,$molarty); 
	print "What is the volume?\n"; 
	$volum = <STDIN>; 
	($volume, $units2) = split(/ /,$volum); 
	chomp($units1); 
	chomp($units2); 
		print "The volume is $volume $units2 and the molarity is $molarity $units1\n"; 
	my $units1 = $units{$units1}; 
	my $units2 = $units{$units2}; 
	my $moles = $molarity*$units1*$volume*$units2; 
	print "There are $moles moles"; 
} 
 
if ($input == 2) { 
	print "Working out the volume...\n"; 
	print "What is the molarity?\n"; 
	$molarty = <STDIN>; 
	($molarity, $units1) = split(/ /,$molarty); 
	print "How many moles are there?\n"; 
		$mol = <STDIN>; 
		($moles, $units2) = split(/ /, $mol); #splits the input into the number and the units (string) 
		chomp($units1); 
		chomp($units2); 
	print "The molarity is $molarity $units1 and there are $moles $units2 \n"; 
	my $units1 = $units{"$units1"};	 
	my $units2 = $units{"$units2"}; 
	my $volume = (($moles*$units2)/($molarity*$units1)); 
	print "The volume of the solution is $volume Litres"; 
 
	 
} 
 
if ($input == 3){ 
	print "working out the molarity...\n"; 
	print "what is the volume?\n"; 
	$volum = <STDIN>; 
	($volume, $units1) = split(/ /,$volum); #splits the input into the number and the units (string) 
	print "what is the number of moles?\n"; 
	$mol = <STDIN>; 
	($moles, $units2) = split(/ /, $mol); #splits the input into the number and the units (string) 
	chomp($units1); 
	chomp($units2); 
		print "The volume is $volume $units1 and the there are $moles $units2\n"; 
	my $units1 = $units{"$units1"};	 
	my $units2 = $units{"$units2"}; 
		print "$moles $units2 $volume $units1 \n"; 
	my $molarity = ((($moles)*($units2))/(($volume)*($units1))); 
	print "The molarity of the solution is $molarity M"; 
	 
	 
	 
}