Final answer:
The number 7.7 x 10^-3 mL has two significant digits, which are the digits in the coefficient 7.7 of the scientific notation.
Step-by-step explanation:
The question of how many significant digits are in the number 7.7 x 10^-3 mL relates to the concept of significant figures used in scientific measurements.
To determine the number of significant digits, we can ignore the power of 10 and just focus on the coefficient of the scientific notation.
In this case, the coefficient is 7.7, which has two significant digits. The digits 7 and 7 are both significant because they are both non-zero numbers, and according to the rules of significant figures, all non-zero digits are significant. Additionally, if this number were part of a calculation, such as a multiplication or division, the result should match the number of significant figures in the least precise measurement involved in the calculation.
For example, if 7.7 x 10^-3 mL were used in a multiplication with another number that has three significant figures, the result would be reported with two significant digits since 7.7 is the least precise measurement.