Định lượng photpho trong mau phan bon, cân 1g mẫu và tạo tủa dưới dang Mg NH4PO4.Nung tủa ở 600°c được dạng cân Mg2p2o7 co khoi luong 0,2350g tính %P

c- cold periods in earth's history during which glaciers covered much of the surface.

explanation:

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.

it should have an internal chamber and two thermometers sticking out of the top. the internal chamber will also be closed off from the outside.