Which balanced equation represents a chemical change?

(1) H2O (l) + energy → H2O (g)

(2) 2H2O (l) + energy → 2H2 (g) + O2 (g)

(3) H2O (l) → H2O (s) + energy

(4) H2O (g) → H2O (l) + energy

Round off the following to three significant figures 0.032000000cg

The enthalpy of combustion of acetylene C2H2 is described by C2H2 (g) + (5/2) O2 (g) →2CO2 (g) + H2O (l),  H rxn = - 1299 kJ/mol.

Determine valence electrons

How many moles of nitrogen gas are there in 16.8 L of this gas at STP?

The transfer of energy between algae and herbivores is about 5 percent. 10 percent. 2 percent. 1 percent.

Calculate how many Calories would be found in a breakfast consisting of the following: two eggs two pieces of toast buttered with one tablespoon of butter one 9 oz glass of orange juice

What are the electron configurations of an electrically neutral atom of sodium, electrically neutral atom of neon, and electrically neutral atom of oxygen?

Which is a product in the following chemical reaction? CH4 + 2O2 → CO2 + 2H2O CH4 H4 H2O O2

How many Mg atoms are present in 170g of Mg

The kinetic theory assumes that collisions of gas particles are perfectly elastic. What does this statement mean?