PLEASE HELP! Determine the volume of 1M NaOH that is required to reach the equivalence point with 25.00 mL of HCl (of unknown concentration). From there, calculate the original concentration of the unknown HCl solution.

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Listen base your answer to the question on the information below.propane is a fuel that is sold in rigid, pressurized cylinders. most of the propane in a cylinder is liquid, with gas in the space above the liquid level. when propane is released from the cylinder, the propane leaves the cylinder as a gas. propane gas is used as a fuel by mixing it with oxygen in the air and igniting the mixture, as represented by the balanced equation below.c3h8(g) + 5o2(g) → 3co2(g) + 4h2o() + 2219.2 kja small amount of methanethiol, which has a distinct odor, is added to the propane to consumers detect a propane leak. in methanethiol, the odor is caused by the thiol functional group (–sh). methanethiol, ch3sh, has a structure that is very similar to the structure of methanol.what is the correct structural formula for a molecule of methanethiol

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.