It takes 75 ml of a 2.5 M HCl solution to neutralize 55 mL of a base of unknown concentration. calculate the concentration of an unknown basic solution.

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.

How many neutrons does an element have if its atomic number is 50 and its mass number is 166