Calculate the molar concentration of 0.125 mass percent NaCl solution ( the density of the solution is 1.00g/ml)

Joan writes four numbers on the board in standard form, and then she writes their scientific notation

Apiece of metal with a length of 1.42 cm was measured using four different instruments. which of the following measurements is the most accurate?

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.