Which element is the excess reagent when 3.00 moles of Mg is ignited in 2.20 moles of pure oxygen in the reaction below?

2Mg + O2 -> 2MgO

1) these are barrel shaped microtubules in most animal cells, that organize the spindles during cell division

Answer asap need 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.

Which change to the system wood cause the freely-moving piston to lower?