Mosses growing on surface of rocks, producing pits in rocks. What is it mechanical or chemical?

Which force always attracts objects to each other?

Which type of reactions form salts? neutralization reactions highly basic reactions highly acidic reactions

Which of the following outer electron configurations would you expect to belong to a reactive metal? a. ns2 b. ns2 np6 c. ns2 np5 d. ns2 np2

Rank the following substances in order from most soluble in water to least soluble in water: ethane, C2H6; 2-butanol, C4H9OH; copper (II) sulfate, CuSO4; and propane, C3H8.

A chemical system at equilibrium is referred to as dynamic because the A) rates of the forward and reverse reactions continue changing B) forward and reverse reactions continue reacting C) value of the equilibrium constant (K) changes D)

The graph below shows how solubility changes with temperature. What is the solubility of Na2HAsO4 at 60°C? 20 g/100 mL of water 46 g/100 mL of water 65 g/100 mL of water 70 g/100 mL of water

Which statement regarding water is true? Energy must be given off in order to break down the crystal lattice of ice to a liquid. Hydrogen bonds are stronger than covalent bonds. Liquid water is less dense than solid water.

Which of the following elements has the fewest valence electrons?. a. beryllium. b. boron. c. carbon. d. lithium

How many molecules are in 4.50 moles of H2O? A. 450 molecules B. 6.02 x 1023 molecules C. 2.71 x 1024 molecules D. 3.00 molecules

A sample of pure calcium fluoride with a mass of 15.0 g contains 7.70 g of calcium. How much calcium is contained in 45.0 g of calcium fluoride