//Acids & Bases - Titration Calculations Script
thepage="Titration Calculations"
//updated 12/02/02-netscape 7
//global variables
//refnumber=122
theanswer=""
attempts=0
tried=0
anrs=0
corrt=0
totl=0
theanswer=""
vol=0
mass=0
gew=0
equiv=0
whichvol=0
whichmass=0
equation=new Array()
function question(p1,p2,p3,p4){
	this.p1=p1
	this.p2=p2
	this.p3=p3
	this.p4=p4
}
munit=new Array("g","mg")
vunit=new Array("L","mL")
vol=new Array()
mass=new Array()
quest=new Array()
quest[1]=new question("What volume in "," of .100M NaOH would be required to titrate a "," sample  of a weak acid with an equivalent weight of "," ?")
quest[2]=new question("The titration of a "," sample of a weak acid requires "," of .100M NaOH. What is the equivalent weight of the acid?","")
quest[3]=new question("The titration of a sample of a weak acid with an equivalent weight of "," grams/mol requires "," of 0.100M NaOH. What is the sample mass in ","?")
ansphrase=new Array()
ansphrase[1]=new Array("First, calculate moles of acid present by dividing the mass in grams by the equivalent weight.<br>","<br>The volume of base needed is the equivalents divided by the molarity of the base.<br>")
ansphrase[2]=new Array("First, calculate moles of base used by multiplying the concentration of base times the vol(L) used in the titration.<br>","<br>Then, divide the mass of the sample by the moles to get the equivalent weight.<br>")
ansphrase[3]=new Array("First, calculate moles of base used by multiplying the concentration of base times the vol(L) used in the titration.<br>","<br>Then, calculate the mass by multiplying the moles times the equivalent weight.<br>")
function startit(){
	totl++
	document.forms[0].total.value=totl
	clear()
	mass[0]=0
	gew=1000
	while (mass[0]<.2 || mass[0]>.8){
		mass[0]=Math.random()
		}
	mass[0]=number(mass[0],3,3)
	mass[1]=Math.round(1000*mass[0])
	gew=0
	while (gew<40 || gew>200)gew=Math.random()*300;
	gew=number(gew,3,3)
	equiv=number((mass[0]/gew),3,3)
	vol[0]=number((equiv/.1),3,3)
	vol[1]=number((1000*vol[0]),3,3)
	if(vol[1]>40 || vol[1]<10){
		totl--
		startit()
		}
	else{
	which=Math.ceil(3*Math.random())
	which=1
	whichmass=Math.floor(2*Math.random())
	whichvol=Math.floor(2*Math.random())
	massterm=mass[whichmass]+munit[whichmass]
	volterm=vol[whichmass]+vunit[whichmass]
	which=Math.ceil(3*Math.random())
	if (which==1){
		var1=vunit[whichvol]
		var2=massterm
		var3=gew+"grams"
		ansr=vol[whichvol]
		}
	if (which==2){
		var1=massterm
		var2=volterm
		var3=""
		ansr=gew
		}
	if (which==3){
		var1=gew
		var2=volterm
		var3=munit[whichmass]
		ansr=mass[whichmass]
		}
thequest=quest[which]["p1"]+var1+quest[which]["p2"]+var2+quest[which]["p3"]+var3+quest[which]["p4"]
buildanswer(which)	
showquest(thequest)
}}
function buildanswer(which){
	getequations(which)
	theanswer=ansphrase[which][0]+equation[1]+ansphrase[which][1]+equation[2]
}
function getequations(which){
	if(which==1){
		equation[1]="moles=mass/equiv wt="+mass[0]+"/"+gew+"=<b>"+equiv+"moles</b>"
		equation[2]="V=moles/M="+equiv+"/.100=<b>"+vol[0]+"L</b>"
		if(whichvol!=0)equation[2]+="<br>Convert this volume to mL=><b>"+vol[1]+"mL</b>"
	}
	if(which==2){
		equation[1]="moles=M*V(L)="+".100*"+vol[0]+"="+equiv+"moles</b>"
		equation[2]="gew=mass/moles="+mass[0]+"/"+equiv+"=<b>"+gew+"g/mole</b>"
	}
	if (which==3){
		equation[1]="moles=M*V(L)="+".100*"+vol[0]+"="+equiv+"moles</b>"
		equation[2]="mass=moles*gew="+equiv+"*"+gew+"=<b>"+mass[0]+"grams</b>"
		if(whichmass!=0)equation[2]+="<br>Convert this mass to mg=><b>"+mass[1]+"mg</b>"
	}
}
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};
	if(ans>.95*ansr & ans<1.05*ansr){
		document.forms[0].results.value="Correct"
		corrt++
		document.forms[0].correct.value=corrt
		tried=1
	}
	else{
		document.forms[0].results.value="Incorrect"
		tried=2
	}
}}