2 Which equation represents a precipitation reaction? A H2CO3 (aq) CO2 (g) + H20 ()
B H2SO4 (aq) + 2NaOH (aq) Na2SO4 (aq) + 2H20 ()
C2H2 (g) + O2 (g) 2H20 (1)
D AgNO3 (aq) + NaOH (aq) AGOH (s) + NaNO3 (aq)

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

Ahelium balloon contains 16.9 l of helium at stp. how many atoms of helium are in the balloon

Which factor is likely to impact the possible number of compounds? presence of unlimited number of elements in the periodic table the inability of atoms to align perfectly with other atoms the ability of all elements to react with every other element all elements being equally reactive