Assume that the test tube shown started out having 10.00 g of mercury(II) oxide. After heating the test tube briefly, you find 1.35 g mercury(II) oxide left and 8.00 g of liquid mercury. How much oxygen gas was produced by the chemical reaction? Show your work.

Can someone me with 3 and 4 plz. this is for masteries test.

What are several ways to reduce the effect of friction

Which best describes the present-day universe? opaque, expanding very slowly, stars produce heavy elements transparent, expanding at an accelerated rate, stars produce heavy elements opaque, expanding at an accelerated rate, stars produce only hydrogen and helium transparent, expanding very slowly, stars produce only hydrogen and helium