Given 6.98 x 10 4 power grams of iron, calculate the moles of iron present

1249.88 mol.

Explanation:

∵ no. of moles of Fe = mass of Fe/atomic weight of Fe.

∴ no. of moles of Fe = (6.98 x 10⁴ g)/(55.845 g/mol) = 1249.88 mol.

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

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