What is 0.000345 expressed in scientific notation? 3.45 × 102 3.45 × 104 3.45 × 10–2 3.45 × 10–4

Hello you probably have the answer by now. But I just want to help others to know what it is. Just in case they are stuck.

I just took the quiz on e2020 and it is 3.45 × 10^–4. Or letter D or basically last one. Which ever is easier for you but yes those all are the same and the answer.

D

Explanation:

when [oh-] is 10-5  m, and [h3o+] is 10-9  m, the poh is 5 and ph is 9. again in both cases the sum of ph and poh is 14. however, the hydrogen ion concentration is not always going to be equal to exactly 1 x 10 raised to a negative number. for example, we skipped over the value of 2.0 x 10-7.

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