Question

The hydrogen ion concentration of a sodium hydroxide solution is 0.00050 M. How is this concentration written in scientific notation?

A. 5.0 x 10⁻⁴M
B. 50 x 10⁴ M
C. 5.0 x 10⁴ M
D. 50 x 10⁻⁴M

Answer 1

A. 5.0 x 10⁻⁴M

Step-by-step explanation:

Move the decimal point in 0.00050 M to the right, counting the steps required, until it is to the right of the first non-zero number, 5 in this case.

0.00050 M becomes 00005.0 M if we move the decimal point 4 spaces to the right. Moving to the right means taking a negative 1 step each time, The resulting count is -4, since we moved the decimal - 4 steps. This becomes the exponent for the 10: 10^-4. The 5.0 is attached to the 10^-4 to yield 5.0x10^-4 M, the answer.