# Science

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1.Is molar mass always done for one mol of substance?
Let me make up an example:
2H2(g)+O2(g)--> 2H2O When finding molar mas of water would it be 2(2(1.01)+2(16)) or just 2(1.01)+16?

2. I'm not really sure about endergonic exergonic reaction because my teacher is teaching some grade 12 stuff to us. So is this correct decomposition reactions are endergonic so their reverse reaction which is synthesis would be exergonic and dissolving which is a phase change is endergonic?

• Science -

THE molar mass is the mass of one mole so the molar mass of water is about 18 (16+2).

The mass of TWO moles of water is about 36; that is, 2 x mass of 1 mole or 2 x 18 = 36
.

• Science -

Exergonic reactions are spontaneous. Endergonic reactions are non-spontaneous. If a reaction is exergonic its reverse reaction is endogonic.

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