A student noticed a white coating on the magnesium metal before she started lab. She did not clean the surface of the metal. Instead she proceeded with the lab using this piece of magnesium metal. The error caused by not cleaning the magnesium metal would result in A) the mass of the magnesium recorded being erroneously high and the mass of the oxygen calculated being too low. B) the mass of the magnesium recorded being erroneously low and the mass of the oxygen calculated being too low. C) the mass of the magnesium recorded being erroneously high and the mass of the oxygen calculated being too high. D) no error in the final calculated empirical formula.

Acrystal that absorvd water from air is (blank)a. aqueousb. homogenousc. hygroscopicd. efflorescent

Answer asap need to be answered by wednesday morning explain how a buffer works, using an ethanoic acid / sodium ethanoate system including how the system resists changes in ph upon addition of a small amount of base and upon addition of a small amount of acid respectively. include the following calculations in your i. calculate the ph of a solution made by mixing 25cm3 0.1m ch3cooh and 40cm3 0.1m ch3coo-na+. [ka = 1.74 x 10-5 m] ii. calculate the ph following the addition of a 10cm3 portion of 0.08 m naoh to 500cm3 of this buffer solution. iii. calculate the ph following the addition of a 10cm3 portion of 0.08 m hcl to 200cm3 of the original buffer solution.

How many grams of phosphorus are contained in 5.09 moles of phosphorus?