// Gas Laws - Combined Gas Law Script
thepage="Gas Laws - Combined Gas Law"
//11/18/02-updated netscape 7
//global variables
//refnumber=57
attempts=0
which=0
theanswer=0
corrt=0
totl=0
tried=0
missing=""
function parts(p1,p2,p3,p4,p5,p6,p7,p8,p9,p10){
	this.p1=p1
	this.p2=p2
	this.p3=p3
	this.p4=p4
	this.p5=p5
	this.p6=p6
	this.p7=p7
	this.p8=p8
	this.p9=p9
	this.p10=p10
}
theR=new Array(.0821,62.4)
combined="P<SUB>1</SUB>V<SUB>1</SUB>/T<SUB>1</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>/T<SUB>2</SUB>"
comblaws=new Array("=>P<SUB>1</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>T<SUB>1</SUB>/T<SUB>2</SUB>V<SUB>1</SUB>","=>V<SUB>1</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>T<SUB>1</SUB>/T<SUB>2</SUB>P<SUB>1</SUB>","=>T<SUB>1</SUB>=P<SUB>1</SUB>V<SUB>1</SUB>T<SUB>2</SUB>/P<SUB>2</SUB>V<SUB>2</SUB>","=>P<SUB>2</SUB>=P<SUB>1</SUB>V<SUB>1</SUB>T<SUB>2</SUB>/T<SUB>1</SUB>V<SUB>2</SUB>","=>V<SUB>2</SUB>=P<SUB>1</SUB>V<SUB>1</SUB>T<SUB>2</SUB>/T<SUB>1</SUB>P<SUB>2</SUB>","=>T<SUB>2</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>T<SUB>1</SUB>/P<SUB>1</SUB>V<SUB>1</SUB>")
seq=new Array()
seq[0]=new Array(3,4,2,5,1)
seq[1]=new Array(3,4,2,5,0)
seq[2]=new Array(0,1,5,3,4)
seq[3]=new Array(0,1,5,2,4)
seq[4]=new Array(0,1,5,2,3)
seq[5]=new Array(3,4,2,0,1)
labels=new Array("P1","V1","T1","P2","V2","T2")
dimensions=new Array("pressure","volume","temperature","pressure","volume","temperature")
units=new Array(" atm"," L"," K"," atm"," L"," K"," torr"," mL","&deg;C"," torr"," mL","&deg;C")
data=new Array()
question=new Array()
question[0]=new parts("A closed gas system initially has "," with the "," unknown. If the same closed system has values of ",", what was the initial ")
question[1]=new parts("A closed gas system initially has ",". If the ",",respectively, what is the new ")
ansphrase=new parts("First, organize the data converting the temperature, if needed. Also, be certain that the dimensions of the same variable agree:<br>","Rearrange  the combined gas equation to solve for the missing quantity<br>","<br>Substitute in the knowns and solve,using the appropriate ideal gas constant and converting the initial result to the desired dimension, as necessary:<br>")
function startit(){
	clear()
	totl++
	document.forms[0].total.value=totl
	//first calculate three values data[0]=P1,data[1]=V1,data[2]=T1,data[3]=P2...
	P1=number((2*Math.random()),3,3)
	V1=number((10*Math.random()),3,3)
	T1=0
	while(T1<200)T1=number(1000*Math.random(),3,3)
	P2=number((2*Math.random()),3,3)
	V2=number((10*Math.random()),3,3)
	T2=number((P2*V2*T1/(P1*V1)),3,3)
	if(T2<200 || T2>1000){totl--;startit()}
	else{
	//set up arrays with v in L and mL, etc
	data=new Array()
	data[0]=new Array(P1,number((P1*760),3,3))
	data[1]=new Array(V1,number(1000*V1,3,3))
	data[2]=new Array(T1,number((1*T1-273),4,3))
	data[3]=new Array(P2,number((P2*760),3,3))
	data[4]=new Array(V2,number(1000*V2,3,3))
	data[5]=new Array(T2,number((1*T2-273),4,3))
	buildquest()
}}
function buildquest(){
	missing=new Array(Math.floor(3*Math.random()),Math.floor(2*Math.random()))
	toshow=new Array()
	for(var j=0;j<=5;j++){
		if(j!=missing[0]){
		choose=Math.floor(2*Math.random())
		toshow[toshow.length]=dimensions[j]
		toshow[toshow.length]=data[j][choose]
		toshow[toshow.length]=units[j+6*choose]
		data[j][2]=choose
		}
	}
	if(missing[0]<3){
	thequest=question[0].p1+toshow[0]+" and "+toshow[3]+" of "+toshow[1]+toshow[2]+" and "+toshow[4]+toshow[5]+question[0].p2+dimensions[missing[0]]+question[0].p3+toshow[7]+toshow[8]+", "+toshow[10]+toshow[11]+" and " +toshow[13]+toshow[14]+question[0].p4+dimensions[missing[0]]+ " in "+units[missing[0]+6*missing[1]]+"?"
	}
	else{
	thequest=question[1].p1+dimensions[0]+", "+dimensions[1]+" and "+dimensions[2]+" of "+toshow[1]+toshow[2]+", "+toshow[4]+toshow[5]+" and "+toshow[7]+toshow[8]+question[1].p2+toshow[9]+" and "+toshow[12]+" are changed to "+toshow[10]+toshow[11]+" and "+toshow[13]+toshow[14]+question[1].p3+dimensions[missing[0]]+" in "+units[missing[0]+6*missing[1]]+"?"}
	showquest(thequest);
	buildanswer()
}
function buildanswer(){
	datatable=""
	lines=new Array()
	for(j=0;j<=5;j++){
		if(j==missing[0])lines[j]=labels[j]+"=?(in "+units[missing[0]+6*missing[1]]+")";
		else{			
			lines[j]=labels[j]+"="+data[j][data[j][2]]+units[j+6*data[j][2]]
			if(Math.abs(j-missing[0])==3){
				if(j!=2 & j!=5){
				if(data[j][2]!=missing[1])lines[j]+=("=>"+data[j][missing[1]]+units[missing[0]+6*missing[1]]);
				}}
			if((j==2 || j==5) & data[j][2]==1)lines[j]+=("=>"+data[j][0]+"K");
		}	
	}
	if(missing[0]!=1 & missing[0]!=4){
			if(data[1][2]!=data[4][2])lines[4]+=("=>"+data[4][data[1][2]]+units[1+6*data[1][2]]);
		}
	if(missing[0]!=0 & missing[0]!=3){
			if(data[0][2]!=data[3][2])lines[3]+=("=>"+data[3][data[0][2]]+units[0+6*data[0][2]]);
		}
	for(j=0;j<=5;j++)datatable+=lines[j]+"<br>";
	theanswer=datatable
	finish=buildeqn()
	theanswer=ansphrase.p1+datatable+ansphrase.p2+combined+comblaws[missing[0]]+ansphrase.p3+finish
	//showanswer()
}
function buildeqn(){
	st=missing[0]
	theeqn="("+data[seq[st][0]][0]+"*"+data[seq[st][1]][0]+"*"+data[seq[st][2]][0]+")/("+data[seq[st][3]][0]+"*"+data[seq[st][4]][0]+")"+"="
	if(missing[0]==2 || missing[0]==5){
		theeqn+=data[missing[0]][0]+"K";
		if(missing[1]==1)theeqn+="=>"+data[missing[0]][1]+"<sup>o</sup>C";
	}
	else{
		theeqn+=data[missing[0]][missing[1]]+units[missing[0]+6*missing[1]];
	}
	return theeqn
}
function answer(theans){
	if(tried==1)alert("You've done this one! Get a new problem.");
	else{
	if(tried==2){totl++;document.forms[0].total.value=totl};
	attempts++
	if(data[missing[0]][missing[1]]<0 && theans<0){
		if(theans<.95*data[missing[0]][missing[1]] & theans>1.05*data[missing[0]][missing[1]]){
			document.forms[0].results.value="Correct"
		corrt++
		document.forms[0].correct.value=corrt
		tried=1
		}
		else{
			document.forms[0].results.value="Incorrect"
			tried=2
		}
	}
	else{
	if(theans>.95*data[missing[0]][missing[1]] & theans<1.05*data[missing[0]][missing[1]]){
		document.forms[0].results.value="Correct"
		corrt++
		document.forms[0].correct.value=corrt
		tried=1
	}
	else{
		document.forms[0].results.value="Incorrect"
		tried=2
	}}
}}