//updated 11/14/00-added complete solution
thepage="Molarity - Word Problem"
//11/20/02-updated netscape 7
//global variables
//refnumber=72
corrt=0
tried=0
totl=0
theanswer=""
alldata=0
solved=0
cmpd=0
aindex=0
function item(name,formula,gfw){
	this.name=name
	this.formula=formula
	this.gfw=gfw
}
compound=new Array(20)
compound[1]=new item("sodium chloride","NaCl",58.5)
compound[2]=new item("sodium nitrate","NaNO<sub>3</sub>",85)
compound[3]=new item("ammonium chloride","NH<sub>4</sub>Cl",53.5)
compound[4]=new item("calcium nitrate","Ca(NO<sub>3</sub>)<sub>2</sub>",164)
compound[5]=new item("methanol","CH<sub>4</sub>O",32)
compound[6]=new item("ethanol","C<SUB>2</SUB>H<sub>6</sub>O",46)
compound[7]=new item("acetone","C<SUB>3</SUB>H<sub>6</sub>O",58)
compound[8]=new item("barium nitrate","Ba(NO<sub>3</sub>)<sub>2</sub>",261.4)
compound[9]=new item("sodium iodide ","NaI",150)
compound[10]=new item("sodium bromide","NaBr",103)
compound[11]=new item("ferric chloride","FeCl<SUB>3</SUB>",162)
compound[12]=new item("cobalt(II) chloride","CoCl<SUB>2</SUB>",130)
compound[13]=new item("sucrose","",342.3)
compound[14]=new item("lithium iodide","LiI",137)
compound[15]=new item("potassium fluoride","KF",58.1)
compound[16]=new item("potassium chloride","KCl",74.5)
compound[17]=new item("calcium chloride","CaCl<SUB>2</SUB>",111)
compound[18]=new item("barium iodide","BaI<SUB>2</SUB>",391)
compound[19]=new item("ammonium nitrate","NH<sub>4</sub>NO<sub>3</sub>",80)
compound[20]=new item("ammonium bromide","NH<sub>4</sub>Br",98)
question=new Array()
question[0]=new Array("What volume in "," of a ","<u>M</u> solution of "," would be required if you wanted ","  of solute?")
question[1]=new Array("How many "," are in  "," of a ","<b>M</b> solution of ","?")
question[2]=new Array("What is the molarity of a solution of "," which contains "," of solute in a total volume of ","?")
datalabels=new Array("<u>M</u>","moles","L","mL"," grams "," mg ","gfw")
equation=new Array()
equation[0]=new Array("Calculate the molarity:<br>",datalabels[1]+"/"+datalabels[2]+"="+datalabels[0])//N/v=M
equation[1]=new Array("Calculate the number of moles:<br>",datalabels[0]+"*"+datalabels[2]+"="+datalabels[1])//M*V=n
equation[2]=new Array("Calculate the volume(L):<br>",datalabels[1]+"/"+datalabels[0]+"="+datalabels[2])//n/M=V
equation[3]=new Array("Convert moles to grams using the gfw:<br>",datalabels[1]+"*"+datalabels[6]+"="+datalabels[4])//n*gmw=mass
equation[4]=new Array("Convert grams to moles using the gfw:<br>",datalabels[4]+"/"+datalabels[6]+"="+datalabels[1])//m/gmw=n
equation[5]=new Array("Convert L to mL:<br>",datalabels[2]+"*1000="+datalabels[3])//L*1000=mL
equation[6]=new Array("Convert mL to L:<br>",datalabels[3]+"/1000="+datalabels[2])//mL/1000=L
equation[7]=new Array("Convert g to mg:<br>",datalabels[4]+"*1000="+datalabels[5])//g*1000=mg
equation[8]=new Array("Convert mg to g:<br>",datalabels[5]+"/1000="+datalabels[4])//mg/1000=g
problemlist=new Array(12,13,42,43,52,53,112,113,142,143,152,153,212,213,242,243,252,253)
eqnsets=new Array()
eqnsets[0]=new Array("2")
eqnsets[1]=new Array(2,5)
eqnsets[2]=new Array(4,2)
eqnsets[3]=new Array(4,2,5)
eqnsets[4]=new Array(8,4,2)
eqnsets[5]=new Array(8,4,2,5)
eqnsets[6]=new Array("1")
eqnsets[7]=new Array(6,1)
eqnsets[8]=new Array(1,3)
eqnsets[9]=new Array(6,1,3)
eqnsets[10]=new Array(1,3,7)
eqnsets[11]=new Array(6,1,3,7)
eqnsets[12]=new Array("0")
eqnsets[13]=new Array(6,0)
eqnsets[14]=new Array(4,0)
eqnsets[15]=new Array(4,6,0)
eqnsets[16]=new Array(8,4,0)
eqnsets[17]=new Array(8,4,6,0)
function startit(){
	totl++
	document.forms[0].total.value=totl
	clear()
	molarity=0
	vL=0
	while(vL<.01)vL=Math.random()
	vmL=1e3*vL
	choice=Math.ceil(20*Math.random())
	cmpd=new Array()
	cmpd[0]=compound[choice].name
	cmpd[1]=compound[choice].formula
	M=0
	while (M<.05)M=2*Math.random();
	n=M*vL
	gmass=n*compound[choice].gfw
	mgmass=1000*gmass
	vL=number(vL,3,3)
	vmL=number(vmL,3,3)
	M=number(M,3,3)
	n=number(n,3,3)
	gmass=number(gmass,3,3)
	mgmass=number(mgmass,3,3)
	alldata=new Array(M,n,vL,vmL,gmass,mgmass,compound[choice].gfw)
	buildquestion()
	showquest(thequest)
}
function buildquestion(){
	which=Math.floor(3*Math.random())
	Math.random()>.5?vunit=2:vunit=3;
	Math.random()>.5?gunit=4:gunit=5;
	Math.random()>.5?first=1:first=(3+Math.ceil(2*Math.random()));
	probkey=1*(""+which+first+vunit)
	if(which==0){thequest=question[which][0]+datalabels[vunit]+question[which][1]+alldata[0]+question[which][2]+cmpd[Math.floor(2*Math.random())]+question[which][3]+alldata[first]+datalabels[first]+question[which][4]
		aindex=vunit}
	if(which==1){
	thequest=question[1][0]+datalabels[first]+question[1][1]+alldata[vunit]+datalabels[vunit]+question[1][2]+alldata[0]+question[which][3]+cmpd[Math.floor(2*Math.random())]+question[1][4]
		aindex=first}
	if(which==2){
		thequest=question[2][0]+cmpd[Math.floor(2*Math.random())]+question[2][1]+alldata[first]+datalabels[first]+question[2][2]+alldata[vunit]+datalabels[vunit]+question[which][3]
		aindex=0}
	buildanswer(probkey)
	showquest(thequest)
}
function buildanswer(probkey){
	getsolved()
	for(var j=0;j<18;j++){
		if(probkey==problemlist[j])foundit=j
	}
	theanswer=""
	for( var j=0;j<eqnsets[foundit].length;j++)theanswer+=equation[eqnsets[foundit][j]][0]+equation[eqnsets[foundit][j]][1]+" &#8594; "+solved[eqnsets[foundit][j]]+"<br>";
}		
function getsolved(){
	solved=new Array()
	solved[0]=alldata[1]+"/"+alldata[2]+"="+alldata[0]//N/v=M
	solved[1]=alldata[0]+"*"+alldata[2]+"="+alldata[1]//M*V=n
	solved[2]=alldata[1]+"/"+alldata[0]+"="+alldata[2]//n/V=M
	solved[3]=alldata[1]+"*"+alldata[6]+"="+alldata[4]//n*gmw=mass
	solved[4]=alldata[4]+"/"+alldata[6]+"="+alldata[1]//m/gmw=n
	solved[5]=alldata[2]+"*1000="+alldata[3]//L*1000=mL
	solved[6]=alldata[3]+"/1000="+alldata[2]//mL/1000=L
	solved[7]=alldata[4]+"*1000="+alldata[5]//g*1000=mg
	solved[8]=alldata[5]+"/1000="+alldata[4]//mg/1000=g
}
function answer(ans){
	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 (ans>.95*alldata[aindex] & ans<1.05*alldata[aindex]){
    			document.forms[0].results.value="correct"
			corrt++
    			document.forms[0].correct.value=corrt
			tried=1
			}
		else{tried=2;document.forms[0].results.value="incorrect"}
}}