The mass of a sample weighed on an electronic balance that is sensitive to 0.3 mg is 1.2300 g. the number of significant figures in this measurement is

The sensitivity of electronic balance is 0.3 mg

Converting 0.3 mg to g:

g

So, the mass of a substance weighed on the balance can be measured accurately up to four decimal places.

Given the mass of sample is 1.2300 g. The number of significant figures in the measurement will be 5 because the balance can measure the mass of a sample accurately up to four decimal points, all the digits in the measurement will be significant.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

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