Which of the following items represents a chemical change? burning

melting

evaporation

freezing

What is the reaction quotient for the following reaction; A B + 2C? A. B. C. D.

What is hydrogen bond?

The effects of acid rain include: a. acidic lakes and streams b. erosion of heavy metals into the water cycle c. damage to leaves d. all of the above

A hot-water heater has an 8-ohm element that operates at 240 V. The power that's consumed by this water heater is A. 1,920 W. B. 30 W. C. 900 W. D. 7,200 W.

How many grams of KBr are required to make 350. mL of a 0.115 M KBr solution?

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.