You have 100 g of pb(no3)2. how many moles is this?

0.302 moles

Explanation:

Data given

Mass of Pb(NO₃)₂ = 100 g

Moles of Pb(NO₃)₂ = ?

Solution:

To find mole we have to know about molar mass of Pb(NO₃)₂  

So,

Molar mass of Pb(NO₃)₂  = 207 + 2[14 + 3(16)]

                                           = 207 + 2[14 + 48]

                                           = 207 + 124

Molar mass of Pb(NO₃)₂  = 331 g/mol

Formula used :

                no. of moles = mass in grams / molar mass

Put values in above formula

                   no. of moles = 100 g / 331 g/mol

                   no. of moles = 0.302 moles

no. of moles of  Pb(NO₃)₂ = 0.302 moles

when the volume of gas is   changed from   717.73 ml   to 852 ml   the temperature will   change   from 315   c to 452   c

    calculation

this is calculated using the charles law formula

that is,   v1/t1 = v2/t2

          v1=?

        t1 = 315 c   into   kelvin = 315 +273 = 588 k

        v2 = 852   ml

        t2 = 425c + 273 =698 k

make v1   the subject of the formula ( by   multiplying both side by t1)

  v1=( v2 xt1) / t2

v1= (852 ml   x 588 k)/ 698 k= 717.73 ml