Answer number 4 & part a pleasd

Answer asap need by wednesday morning calculate the ph of 0.036m naoh best answer will be brainliest

How do you know when a chemical reaction has occurred

Which of the following is a conclusion that resulted from ernest rutherford’s scattering experiment? (will mark brainliest) a. the nucleus is negatively charged b. the atom is a dense solid and is indivisible c. the mass is conserved when atoms react chemically d. the nucleus is very small and the atom is mostly empty space