You have a 155-g sample of Al2O3. If there are 22.5 g of Al in the solution, what is the percent by mass of the solute? Show work.

Iwill give extra points to who gets this right

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

Achemistry student weighs out 0.306 g of citric acid (h3c6h5o7), a triprotic acid, into a 250 ml volumetric flask and dilutes to the mark with distilled water. he plans to titrate the acid with 0.1000 m naoh solution. calculate the volume of naoh solution the student will need to add to reach the final equivalence point. be sure your answer has the correct number of significant digits.