A student in a lab holds an iron nail over an open flame, and no reaction occurs. The nail is then filed, creating small pieces of iron shavings. These pieces burn brightly when placed over an open flame.
Which statement accurately identifies one of the changes that occurs as a physical or chemical change?

Formation of small pieces of iron shavings is a physical change whereas burning of pieces of iron shavings is chemical change.

Formation of small pieces of iron shavings is an example of physical change because it can be changed again into nail while on the other hand, burning of pieces of iron shavings on the flame is an example of chemical change because it can't change again into its original shape. Physical change is a change in matter which does not change the chemical properties of the matter whereas chemical change is a change in matter which change the chemical properties of the matter.

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