What is a better indicator in the titration of HCl with Na2CO3, methyl orange or methyl red, and why​

The rate constant for the reaction below is 6.2 x 10−5 mol l−1 s −1. if the initial concentration of a is 0.0500 m, what is its concentration after 115 s?

How many liters of water can be produced from 5.0liters of butane gas at stp, assuming excess oxygen? c4h10(g) + 02(g) → co2 (e) + h2o (g)

Which of the following statements best explains why chemistry is testable a) it can measure data by experiments b) it cannot add new evidence c) it cannot be verified d) it is biased