Can friction apply to wooden blocks?

Harvey mixes two liquids. which observation of the new mixture most likely indicates a precipitate is forming?

What is the mass of 0.46 mol of mgcl2

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.