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

Will an object with a density of 0.97 g/ml float or sink in water

5. How many significant figures are in the measurement + 0.500 mg? two three four five

What volume of 12.0 m hcl (aq) is required to make 75.0 ml of 3.50m hcl (aq) ?

How many moles of sodium chloride are there in 250 ml of a 1.20 m solution of nacl? 1. none of these 2. 0.60 3. 1.2 4. 2.4 5. 0.30 6. 4.8?

Mathematically define heat capacity

Which usually has a higher temperature? A city or the areas around the city?

Toluene and pyridine form ideal solutions. Consider a solution of toluene and pyridine prepared at 25°C. Assuming that the mole fractions of toluene and pyridine in the vapor phase are equal, calculate the composition of the solution.

Formula for water what does the lack of a subscript after those O indicate

Why do the chemical properties cycle through each period? Every eighth element starting with hydrogen restarts the transition from metal to inert gas. Elements with atomic numbers which are multiples of eight start a new period.

Which statement correctly describes the Ka of a weak acid? The Ka is large, and the equilibrium favors products. The Ka is large, and the equilibrium favors reactants. The Ka is small, and the equilibrium favors products.