During an experiment, ellie records a measurement of 0.00000225 m. how would she write her measurement in scientific notation?

Scientific notation can be written for a number between 0 to 10 written to a power of 10. 
the number given is 0.00000225 M
the first non zero digit from left to right is 2
therefore we need to move the decimal place from the original position in the measurement to the place after the first non zero digit 
so the decimal place moves from 0.00000225 to 2.25
since we have to move the decimal place by 6 places it means that we are multiplying 0.00000225 by 10⁶
then when we write in the scientific notation 0.00000225 is 2.25 x 10⁻⁶
answer is 2.25 x 10⁻⁶ M