Object a at 40ºc and object b at 80ºc are placed in contact with each other. which statement describes the heat flow between the objects?
a)heat flows from object a to object b. b)heat flows from object b to object a. c)heat flows in both directions between the objects. d)no heat flow occurs between the objects.

Compare and contrast physical changes with chemical changes.

The following reaction shows sodium carbonate reacting with calcium hydroxide. na2co3 + ca(oh)2 → naoh + caco3 how many grams of naoh are produced from 20.0 grams of na2co3? (molar mass of na = 22.989 g/mol, c = 12.01 g/mol, o = 15.999 g/mol, ca = 40.078 g/mol, h = 1.008 g/mol) 12.2 grams 15.1 grams 24.4 grams 30.2 grams

All of the following are part of the biosphere except