Ms. Laurent assigned the following equations for single replacement reactions to her students. (i) 2AgNO3 + Cu rightwards arrow Cu(NO3)2 + 2Ag

(ii) 2KI + Cl2 rightwards arrow2KCl + I2

(iii) ZnS + O2 rightwards arrow ZnO + 2S

She asked the students to identify the equations that support the law of conservation of matter. Which of the equations should the students identify?

Achemistry student needs to standardize a fresh solution of sodium hydroxide. he carefully weighs out of oxalic acid , a diprotic acid that can be purchased inexpensively in high purity, and dissolves it in of distilled water. the student then titrates the oxalic acid solution with his sodium hydroxide solution. when the titration reaches the equivalence point, the student finds he has used of sodium hydroxide solution.calculate the molarity of the student's sodium hydroxide solution. be sure your answer has the correct number of significant digits.