// Gas Laws - Boyle's Law Script
thepage="Gas Laws - Boyle's Law"
//11/18/02-updated netscape 7
//global variables
//refnumber=53
attempts=0
tried=0
which=0
theanswer=0
corrt=0
totl=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
}
boyles="<br>P<SUB>1</SUB>V<SUB>1</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>"
blaws=new Array("=>P<SUB>1</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>/V<SUB>1</SUB>","=>V<SUB>1</SUB>=P<SUB>2</SUB>V<SUB>2</SUB>/P<SUB>1</SUB>","=>P<SUB>2</SUB>=P<SUB>1</SUB>V<SUB>1</SUB>/V<SUB>2</SUB>","=>V<SUB>2</SUB>=P<SUB>1</SUB>V<SUB>1</SUB>/P<SUB>2</SUB>")
seq=new Array(2,3,1,2,3,0,0,1,3,0,1,2)
labels=new Array("P<SUB>1</SUB>","V<SUB>1</SUB>","P<SUB>2</SUB>","V<SUB>2</SUB>")
dimens=new Array("pressure","volume","pressure","volume")
units=new Array(" atm"," L"," atm"," L"," torr"," mL"," torr"," mL")
data=new Array()
question=new Array()
question[0]=new parts("A gas system has an initial "," of "," with the "," unknown. When the "," changes to "," the "," is found to be "," What was the initial "," in ","?")
question[1]=new parts("A gas system has initial pressure and volume of "," and "," If the "," changes to ",", what will the resultant "," be in ","?")
ansphrase=new parts("First, organize the data converting the quantities into the needed dimensions:<br>","Reaarange Boyle's Law to solve for the missing quantity<br>","<br>Substitute in the knowns and solve:<br>")
function startit(){
	clear()
	totl++
	document.forms[0].total.value=totl
	//first calculate three values data[0]=P1,data[1]=V1,data[2]=P2
	p1=number((10*Math.random()),3,3)
	v1=number((10*Math.random()),3,3)
	p2=number((10*Math.random()),3,3)
	v2=number((p1*(v1/p2)),3,3)
	//set up arrays with pressures in atm and torr and v in L and mL
	data=new Array()
	data[0]=new Array(p1,number((p1*760),3,3))
	data[1]=new Array(v1,number((v1*1000),3,3))
	data[2]=new Array(p2,number((p2*760),3,3))
	data[3]=new Array(v2,number((v2*1000),3,3))
	buildquest()
}
function buildquest(){
	missing=new Array(Math.floor(4*Math.random()),Math.floor(2*Math.random()))
	choose=new Array()
	for(j=0;j<=3;j++)choose[j]=Math.floor(2*Math.random());
	thequest=""
	if(missing[0]==0|| missing[0]==1){
		missing[0]==0?given=1:given=0;
		thequest=question[0].p1+dimens[given]+question[0].p2+data[given][choose[given]]+units[given+4*choose[given]]+question[0].p3+dimens[missing[0]]+question[0].p4+dimens[given]+question[0].p5+data[given+2][choose[given+2]]+units[given+4*choose[given+2]]+question[0].p6+dimens[missing[0]]+question[0].p7+data[missing[0]+2][choose[missing[0]+2]]+units[missing[0]+4*choose[missing[0]+2]]+question[0].p8+dimens[missing[0]]+question[0].p9+units[missing[0]+4*missing[1]]+question[0].p10
	}
	else{
		missing[0]==2?given=3:given=2;
		thequest=question[1].p1+data[0][choose[0]]+units[0+4*choose[0]]+question[1].p2+data[1][choose[1]]+units[1+4*choose[1]]+question[1].p3+dimens[given]+question[1].p4+data[given][choose[given]]+units[given+4*choose[given]]+question[1].p5+dimens[missing[0]]+question[1].p6+units[missing[0]+4*missing[1]]+question[1].p7
	}
	showquest(thequest);
	buildanswer(data,choose)
}
function buildanswer(data,choose){
	datatable=""
	if(missing[0]==0 || missing[0]==2){pdim=missing[1];vdim=choose[1]}
	else {vdim=missing[1];pdim=choose[0]}
	lines=new Array()
	for(j=0;j<=3;j++){
		if(j==missing[0])lines[j]=labels[j]+"=?(in "+units[missing[0]+4*missing[1]]+")<br>";
		else{
			if(j==0 || j==2){
				choose[j]==pdim?lines[j]=labels[j]+"="+data[j][choose[j]]+units[j+4*choose[j]]+"<br>":lines[j]=labels[j]+"="+data[j][choose[j]]+units[j+4*choose[j]]+"=>"+data[j][pdim]+units[j+4*pdim]+"<br>";
			}
			if(j==1 || j==3){
				choose[j]==vdim?lines[j]=labels[j]+"="+data[j][choose[j]]+units[j+4*choose[j]]+"<br>":lines[j]=labels[j]+"="+data[j][choose[j]]+units[j+4*choose[j]]+"=>"+data[j][vdim]+units[j+4*vdim]+"<br>";
			}
		}}
	for(j=0;j<=3;j++)datatable+=lines[j];
	finish=buildeqn()
	theanswer=ansphrase.p1+datatable+ansphrase.p2+boyles+blaws[missing[0]]+ansphrase.p3+finish
}
function buildeqn(){
	st=3*missing[0]
	finish=data[seq[st]][pdim]+"*"+data[seq[st+1]][vdim]+"/"
	missing[0]==1||missing[0]==3?finish+=data[seq[st+2]][vdim]:finish+=data[seq[st+2]][pdim];
	finish+=("="+data[missing[0]][missing[1]])
	return finish
}
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(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
	}
}}