thepage="First order(122)"
//11/20/02-updated netscape 7
refnumber=160
totl=0
corrt=0
tried=0
pleft=0
attempts=0
R=.008314
A=1e12
option=0
theanswer=""
k1=0
k2=0
tried=corrt=totl=0
basetime=0
time=0
solution=""
fillin="<form><input type=text size=8 name=ans>"
//updated 9/7/98 added show answer
//th=0.693/k-for first order
//globals
attempts=0
time=0
dim=""
theanswer=0
startmass=0
left=0
lost=0
pleft=0
plost=0
cpd=""
option=0
which=0
newone=""
dim1=0
dim2=0
function nuclides(sym,halflife,unit){
	this.sym=sym
	this.halflife=halflife
	this.unit=unit
}
function reactionset(react,cmpd,kconst){
	this.react=react
	this.cmpd=cmpd
	this.kconst=kconst
}
function MakeArray(n){
	this.length=n
	for (var i=1;i<=n;i++){
	this[i]= 0}
}
function question(p1,p2,p3,p4,p5){
	this.p1=p1
	this.p2=p2
	this.p3=p3
	this.p4=p4
	this.p5=p5
}
timeunit=new Array("seconds","minutes","hours","days","years")
tfactor=new Array(1,60,60,24,365)
labels=new Array("[]<sub>o</sub>","[]<sub>t</sub>","k","t","[]<sub>t</sub>")
theimage=new Array("<img src=hlife2.gif>","<img src=hlife3.gif>","<img src=hlife4.gif>")
thedata=new Array()
quest=new MakeArray(10)
quest[1]=new question("If the sample originally contains "," grams of the isotope, how many "," will it take until only "," grams remain?")
quest[2]=new question("A sample with an unknown mass of isotope is allowed to decay for "," After that time ","grams remain."," What was the mass of the original sample?")
quest[3]=new question("If the sample originally has "," grams of isotope, what mass will remain after "," ?")
quest[4]=new question("If the sample originally contains "," grams of the isotope, how much will be consumed in "," ?")
quest[5]=new question("A sample containing an unknown mass of isotope is allowed to decay for "," During that time ","grams decay. How many grams of isotope were in the original sample?")
quest[6]=new question("How long will it take, in<b> ","</b>, until only ","% of the original isotope mass remains?")
quest[7]=new question("How long will it take, in<b> ","</b>, for ","% of the original isotope to decay?")
quest[8]=new question("What percentage of the original sample will remain after ","?")
quest[9]=new question("What percentage of the original sample will be consumed in ","?")
quest[11]=new question("If the sample originally contains "," grams of ",", how many "," will it take until only "," grams remain?")
quest[12]=new question("An unknown mass of ",", is allowed to react for "," After that time ","grams remain. What was the mass of the original sample?")
quest[13]=new question("If the sample originally contains "," grams of ",", what mass will remain after "," ?")
quest[14]=new question("If the sample originally contains "," grams of ",", how much will be consumed in "," ?")
quest[15]=new question("An unknown mass of ",", is allowed to react for ",". During that time ","grams react. How many grams of compound were in the original sample?")
quest[16]=new question("How long will it take, in<b> ","</b>, until only ","% of the original  mass remains?")
quest[17]=new question("How long will it take, in<b> ","</b>, for ","% of the original sample to react?")
quest[18]=new question("What percentage of the original sample will remain after ","?")
quest[19]=new question("What percentage of the original sample will be consumed in ","?")
basequest=new MakeArray(5)
basequest[1]=new question("The nuclide "," has a half-life of ")
basequest[2]=new question("The reaction below is first order in "," with a rate constant of ",".")
introphrase=new Array("Regardless of the actual phrasing all of these problems involve the basic equation<br><img src='hlife1.gif'>.<br> First, if the halflife, rather than the k is provided, calculate k using k=.693/halflife. If the time dimension in the problem is different from the unit in k (or the half-life) be certain to convert it. This problem requires that we know the following:<br>","We rearrange the equation to solve for ")
needed=new Array()
needed[1]=needed[11]=new Array(0,1,2,3,0)
needed[2]=needed[12]=new Array(1,2,3,0,1)
needed[3]=needed[13]=new Array(0,2,3,1,2)
needed[4]=needed[14]=new Array(0,2,3,1,2)
needed[5]=needed[15]=new Array(2,3,4,0,1)
needed[6]=needed[16]=new Array(0,1,2,3,0)
needed[7]=needed[17]=new Array(0,1,2,4,0)
needed[8]=needed[18]=new Array(0,2,3,1,2)
needed[9]=needed[19]=new Array(0,2,3,1,2)  
ansphrase=new Array()
nuke=new MakeArray(30)
nuke[1]=new nuclides("<sup>238</sup>U",4.5e9,4)
nuke[2]=new nuclides("<sup>235</sup>U",7.1e8,4)
nuke[3]=new nuclides("<sup>232</sup>Th",1.4e10,4)
nuke[4]=new nuclides("<sup>40</sup>K",1.3e9,4)
nuke[5]=new nuclides("<sup>14</sup>C",5730,4)
nuke[6]=new nuclides("<sup>239</sup>Pu",24000,4)
nuke[7]=new nuclides("<sup>137</sup>Cs",30,4)
nuke[8]=new nuclides("<sup>90</sup>Sr",28.8,4)
nuke[9]=new nuclides("<sup>8</sup>Li",.841,0)
nuke[10]=new nuclides("<sup>11</sup>Be",13.6,0)
nuke[11]=new nuclides("<sup>65</sup>Ge",1.5,1)
nuke[12]=new nuclides("<sup>13</sup>N",9.96,1)
nuke[13]=new nuclides("<sup>24</sup>Na",14.96,2)
nuke[14]=new nuclides("<sup>23</sup>Mg",9.46,1)
nuke[15]=new nuclides("<sup>25</sup>Al",7.24,0)
nuke[16]=new nuclides("<sup>45</sup>Ca",165,3)
nuke[17]=new nuclides("<sup>51</sup>Ti",5.79,1)
nuke[18]=new nuclides("<sup>59</sup>Fe",45.6,3)
nuke[19]=new nuclides("<sup>62</sup>Zn",9.13,2)
nuke[20]=new nuclides("<sup>63</sup>Ga",33,0)
nuke[21]=new nuclides("<sup>73</sup>Se",7.1,2)
nuke[22]=new nuclides("<sup>77</sup>Br",57,2)
nuke[23]=new nuclides("<sup>90</sup>Kr",33,0)
nuke[24]=new nuclides("<sup>84</sup>Rb",33,3)
nuke[25]=new nuclides("<sup>89</sup>Zr",4.18,1)
nuke[26]=new nuclides("<sup>96</sup>Tc",4.35,3)
nuke[27]=new nuclides("<sup>93</sup>Ru",50,0)
nuke[28]=new nuclides("<sup>100</sup>Rh",20.8,2)
nuke[29]=new nuclides("<sup>100</sup>Pd",4.0,3)
nuke[30]=new nuclides("<sup>106</sup>Ag",24,1)
reaction=new MakeArray(30)
reaction[1]=new reactionset("2N<SUB>2</SUB>O<SUB>5</SUB>(g) => 4NO<SUB>2</SUB>(g)  +  O<SUB>2</SUB>(g)","N<SUB>2</SUB>O<SUB>5</SUB>",8.5e-3)
reaction[2]=new reactionset("CH<SUB>3</SUB>NC(g) => CH<SUB>3</SUB>CN(g)","CH<SUB>3</SUB>NC",5.1e-5)
reaction[3]=new reactionset("SO<SUB>2</SUB>Cl<SUB>2</SUB>  =>  SO<SUB>2</SUB>(g) +  Cl2(g)","SO<SUB>2</SUB>Cl<SUB>2</SUB>",150)
reaction[4]=new reactionset("2H<SUB>2</SUB>O<SUB>2</SUB>(aq) + H<SUB>2</SUB>O(l) +  O<SUB>2</SUB>(g)","H<SUB>2</SUB>O<SUB>2</SUB>",6.3e-4)
reaction[5]=new reactionset("N<SUB>2</SUB>O<SUB>4</SUB>(g) => 2NO<SUB>2</SUB>(g)","N<SUB>2</SUB>O<SUB>4</SUB>",.250)
reaction[6]=new reactionset("2HCl(g) => H<SUB>2</SUB>(g) + Cl<SUB>2</SUB>(g)","HCl",.084)
reaction[7]=new reactionset("C<SUB>8</SUB>H<SUB>18</SUB>O<SUB>2</SUB>(g)  =>  2C<SUB>3</SUB>H<SUB>6</SUB>O(g) +  C<SUB>2</SUB>H<SUB>6</SUB>(g)","C<SUB>8</SUB>H<SUB>18</SUB>O<SUB>2</SUB>",1.92e3)
reaction[8]=new reactionset("C<SUB>2</SUB>H<SUB>4</SUB>O(g) => CH<SUB>4</SUB>(g) + CO(g)","C<SUB>2</SUB>H<SUB>4</SUB>O",2.05e-4)
reaction[9]=new reactionset("2N<SUB>2</SUB>O<SUB>5</SUB>(g) => 2N<SUB>2</SUB>O<SUB>4</SUB>(g) + O<SUB>2</SUB>(g)","N<SUB>2</SUB>O<SUB>5</SUB>",6.21e-4)
reaction[10]=new reactionset("C<SUB>12</SUB>H<SUB>22</SUB>O<SUB>11</SUB>(aq) + H<SUB>2</SUB>O  => 2C<SUB>6</SUB>H<SUB>12</SUB>O<SUB>6</SUB> ","C<SUB>12</SUB>H<SUB>22</SUB>O<SUB>11</SUB>",2.3e-5)
reaction[11]=new reactionset("C<SUB>2</SUB>H<SUB>6</SUB>N<SUB>2</SUB>(g) => N<SUB>2</SUB>(g)  +  C<SUB>2</SUB>H<SUB>6</SUB>(g)","C<SUB>2</SUB>H<SUB>6</SUB>N<SUB>2</SUB>",2.55e-3)
reaction[12]=new reactionset("COCl<SUB>2</SUB>(g) =>  CO(g) + Cl<SUB>2</SUB>(g)","COCl<SUB>2</SUB>",.045)
reaction[13]=new reactionset("(CH<SUB>3</SUB>)<SUB>3</SUB>COH + HCl => (CH<SUB>3</SUB>)<SUB>3</SUB>CCl + H<SUB>2</SUB>0","(CH<SUB>3</SUB>)<SUB>3</SUB>COH",12.4)
reaction[14]=new reactionset("HOF(g) => HF(g) +  1/2O<SUB>2</SUB>(g)","HOF",3.85e-4)
reaction[15]=new reactionset("4PH<SUB>3</SUB>(g)  => P<SUB>4</SUB>(g) + 6H<SUB>2</SUB>(g)","PH<SUB>3</SUB>",1.83e-2)
reaction[16]=new reactionset("2NO<SUB>2</SUB>Cl(g) => 2NO<SUB>2</SUB>(g) + Cl<SUB>2</SUB>(g)","NO<SUB>2</SUB>Cl",2.30e-2)
reaction[17]=new reactionset("NO(g) +  N<SUB>2</SUB>O<SUB>5</SUB>(g) => 3NO<SUB>2</SUB>(g)","N<SUB>2</SUB>O<SUB>5</SUB>",.056)
reaction[18]=new reactionset("CH<SUB>3</SUB>CH<SUB>2</SUB>Cl(g) => C<SUB>2</SUB>H<SUB>4</SUB>(g) + HCl(g)","CH<SUB>3</SUB>CH<SUB>2</SUB>Cl",3.55e-3)
reaction[19]=new reactionset("C<SUB>2</SUB>H<SUB>4</SUB>O(g) => CH<SUB>4</SUB>(g) + CO(g)","C<SUB>2</SUB>H<SUB>4</SUB>O",2.05e-4)
//begin program
function startit(){
	clear()
	totl++
	document.forms[0].total.value=totl
	document.forms[0].results.value=""
	getmasses()
	if(Math.random()>10){radioactive()}
	else{chemical()}
}
function radioactive(){
	rxn=""
	g=Math.ceil(30*Math.random())
	atom=nuke[g].sym
	half=number((nuke[g].halflife),3,1)
	if(half<10 & half>.1)shalf=number(half,3,3);
	else shalf=number(half,3,2)
	dim1=nuke[g].unit
	whichquest=Math.ceil(9*Math.random())
	ask=basequest[1].p1+atom+basequest[1].p2+shalf+timeunit[dim1]+"."
	constant=calck(half)
	time=-Math.log(left/startmass)/constant
	dim2=dim1;
	thedata[2]=constant
	thedata[3]=time
	if(time>.01 & time<100)stime=number(time,3,3);
	else stime=number(time,3,2);
	tunit=timeunit[dim2]
	if(whichquest==1){finish=quest[1].p1+startmass+quest[1].p2+tunit+quest[1].p3+left+quest[1].p4;theanswr=time}
	if(whichquest==2){finish=quest[2].p1+stime+tunit+quest[2].p2+left+quest[2].p3+quest[2].p4;theanswr=startmass}
	if(whichquest==3){finish=quest[3].p1+startmass+quest[3].p2+stime+tunit+quest[3].p3;theanswr=left}
	if(whichquest==4){finish=quest[4].p1+startmass+quest[4].p2+stime+tunit+quest[4].p3;theanswr=lost}
	if(whichquest==5){finish=quest[5].p1+stime+tunit+quest[5].p2+lost+quest[5].p3;theanswr=startmass}
	if(whichquest==6){finish=quest[6].p1+tunit+quest[6].p2+pleft+quest[6].p3;theanswr=time}
	if(whichquest==7){finish=quest[7].p1+tunit+quest[7].p2+plost+quest[7].p3;theanswr=time}
	if(whichquest==8){finish=quest[8].p1+stime + tunit+quest[8].p2;theanswr=pleft}
	if(whichquest==9){finish=quest[9].p1+stime+tunit+quest[9].p2;theanswr=plost}
	buildquest(ask,finish,rxn)
	buildanswer(whichquest)
}
function chemical(){
	which=Math.ceil(19*Math.random())
	constant=reaction[which].kconst
	half=calck(constant)
	basetime=-Math.log(left/startmass)/constant
	dim1=0
	if(Math.random()>.5){
		time=converttime(basetime,0,1)
		dim2=1
	}
	else {
		dim2=dim1;
		time=basetime;
		}
	basetime=number(basetime,3,3)
	time=number(time,3,3)
	thedata[2]=constant
	thedata[3]=basetime
	cpd=reaction[which].cmpd
	rxn=reaction[which].react
	ask=basequest[2].p1+cpd+basequest[2].p2+reaction[which].kconst+"sec<sup>-1</sup> "+basequest[2].p3+"<br>"
	whichquest=10+Math.ceil(9*Math.random())
	tunit=timeunit[dim2]
	if(whichquest==11){finish=quest[11].p1+startmass+quest[11].p2+cpd+quest[11].p3+tunit+quest[11].p4+left+quest[11].p5;theanswr=time}
	if(whichquest==12){finish=quest[12].p1+cpd+quest[12].p2+time+tunit+quest[12].p3+left+quest[12].p4;theanswr=startmass}
	if(whichquest==13){finish=quest[13].p1+startmass+quest[13].p2+cpd+quest[13].p3+time+tunit+quest[13].p4;theanswr=left}
	if(whichquest==14){finish=quest[14].p1+startmass+quest[14].p2+cpd+quest[14].p3+time+tunit+quest[14].p4;theanswr=lost}
	if(whichquest==15){finish=quest[15].p1+cpd+quest[15].p2+time+tunit+quest[15].p3+lost+quest[15].p4
theanswr=startmass}
	if(whichquest==16){finish=quest[16].p1+tunit+quest[16].p2+pleft+quest[16].p3;theanswr=time}
	if(whichquest==17){finish=quest[17].p1+tunit+quest[17].p2+plost+quest[17].p3;theanswr=time}
	if(whichquest==18){finish=quest[18].p1+time + tunit+quest[18].p2;theanswr=pleft}
	if(whichquest==19){finish=quest[19].p1+time+tunit+quest[19].p2;theanswr=plost}
	finish="<br>"+finish
	buildquest(ask,finish,rxn)
	buildanswer(whichquest)
}
function getmasses(){
	startmass=0
	while(startmass<1){startmass=Math.ceil(100*Math.random())/10}
	left=startmass
	while(left>.5*startmass || left<.1*startmass)left=startmass*Math.random();
	startmass=number(startmass,3,3)
	left=number(left,3,3)
	lost=number((startmass-left),3,3)
	pleft=number((left/startmass)*100,3,3)
	plost=number((100-pleft),3,3)
	thedata[0]=startmass
	thedata[1]=left
	thedata[4]=lost
	thedata[5]=pleft
	thedata[6]=plost
}
function calck(h){
k=.693/(1*h)
return number(k,3,3)
}
function converttime(time,a,b){
	if(a>b){
		for(j=a;j>b;j--)time=time*tfactor[j]
	}
	else{
	for(j=a+1;j<=b;j++)time=time/tfactor[j]
	}
	return time
}
function buildquest(ask,finish,rxn){
	thequest=ask+rxn+finish
	showquest(thequest)
}
function buildanswer(whichquest){
	insert=""
	if((whichquest>5 & whichquest<10)||whichquest>15)insert=getinsert(whichquest);
	theanswer=introphrase[0]+insert
	for(j=0;j<3;j++)theanswer+=("<br>"+labels[needed[whichquest][j]]+"="+thedata[needed[whichquest][j]]);
	theanswer+="<br>"+introphrase[1]+labels[needed[whichquest][3]]+"<br>"+theimage[needed[whichquest][4]]+"<br>"+getfinish(whichquest)
}
function getinsert(){
	insert="Since this problem deals with %, the []<sub>o</sub> is set as 100."
	thedata[0]=100
	thedata[1]=pleft
	return insert
} 
function getfinish(whichquest){
	conclude=""
	if(whichquest==1|| whichquest==11 || whichquest==6 || whichquest==16){
		conclude="time=-ln("+thedata[1]+"/"+thedata[0]+")*(1/*"+thedata[2]+")="+number(thedata[3],3,2)
	}
	if(whichquest==2||whichquest==12){
		conclude=labels[0]+"="+thedata[1]+"/e<sup>-"+number(thedata[2],3,2)+"*"+number(thedata[3],3,2)+"</sup>="+thedata[0]
	}
	if(whichquest==3|| whichquest==13||whichquest==18 ||whichquest==8){
		conclude=labels[1]+"="+thedata[0]+"*e<sup>-"+number(thedata[2],3,2)+"*"+number(thedata[3],3,2)+"</sup>="
		if(whichquest==3 || whichquest==13)conclude+=+thedata[1];
		else conclude+=thedata[5]
	}
	if(whichquest==4|| whichquest==14|| whichquest==9 || whichquest==19){
		conclude="For this problem, we can use the relation []<SUB>r</SUB>=[]<SUB>o</SUB>*(1-e<SUP>-kt</SUP>)<br>"
		conclude+=labels[4]+"="+thedata[0]+"*(1-e<sup>-"+number(thedata[2],3,2)+"*"+number(thedata[3],3,2)+"</sup>)="
		if(whichquest==4 || whichquest==14)conclude+=+thedata[4];
		else conclude+=thedata[6]
	}
	if(whichquest==5|| whichquest==15){
		conclude="For this problem, we can use the relation []<SUB>o</SUB>=[]<SUB>r</SUB>/(1-e<SUP>-kt</SUP>)<br>"
		conclude+=labels[0]+"="+thedata[4]+"/(1-e<sup>-"+number(thedata[2],3,2)+"*"+number(thedata[3],3,2)+"</sup>)="+thedata[0]
	}
	if(whichquest==7|| whichquest==17){
		conclude="Since the percent remaining equals 100-%reacted<br>"
		conclude+="time=-ln("+thedata[1]+"/"+thedata[0]+")*(1/*"+thedata[2]+"="+number(thedata[3],3,2)
	}
	if(whichquest==1|| whichquest==11 || whichquest==6 || whichquest==16|| whichquest==7 || whichquest==17){
		if(basetime!=time)conclude+="<br>Then convert the time to the desired units:"+time;
	}
	return conclude
}
		
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*theanswr & ans<1.05*theanswr){
		document.forms[0].results.value="correct"
		corrt++
		document.forms[0].correct.value=corrt
		}
	else{
		document.forms[0].results.value="incorrect"
		tried=2
	}
}}