Two friends push with great force against a rock. The forces are equally strong but in opposite directions. A heavy box rests on top of the rock. Answer these questions about the motion of the rock. Assume that the rock is light enough for either friend to carry. Does the rock move? If so, in which direction does it move? Explain.

Which statement is true about a catalyst? a: a catalyst decreases the rate of the reaction. b. a catalyst is consumed during a chemical reaction. c. a catalyst lowers the activation energy of a reaction. d. a catalyst increases the reactant concentration during a reaction.

The table lists the lattice energies of some compounds. compoundlattice energy (kj/mol)lif            –1,036licl            –853naf            –923kf            –821nacl            –786which statement about crystal lattice energy is  best  supported by the information in the table? the lattice energy increases as cations get smaller, as shown by lif and kf. the lattice energy increases as the cations get larger, as shown by lif and licl. the lattice energy decreases as cations get smaller, as shown by nacl and naf. the lattice energy decreases as the cations get smaller, as shown by naf and kf.

Which action would reduce the activation energy of a chemical reaction? a. adding a catalyst to the reaction b. adding more reactants to the reaction vessel c. lowering the potential energy of the products d. lowering the potential energy of the reactants e. raising the temperature of the reaction