PLEASE HELP PLEASE Octane (C8H18) is a component of gasoline that burns
according to the following equation:
C8H18(l) + 25/2 O2(g) →8 CO2(g) + 9 H2O(g)
ΔΗχη= -5074.1 kJ
What mass of octane (in g) is required to produce 4910kJ of heat?

Asolution at 25 degrees celsius is 1.0 × 10–5 m h3o+. what is the concentration of oh– in this solution?

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

This chart lists four kinds of polymers and their sources. what can be known about all four polymers, despite their differences? they come from living things. they share ionic carbon bonds. they are at least 100 monomers long. they are made of repeating subunits.