Which energy change best relates to a boulder that is rolling down the side of a hill?

A positively charged subatomic particle

The diagram shows Niels Bohr's model of an atom. What happens when the electron moves from the first energy level to the second energy level?

An aqueous solution containing both Sr2 + and CO32 - ions is mixed in order to precipitate SrCO3 (s). given there are 1.40 mL of 2.53 M Sr2 + ions, calculate the mass of SrCO3 that is formed. assume that all of the Sr2 + ions are consumed.

A 55.0 L steel tank at 20.0 ∘C contains acetylene gas, C2H2, at a pressure of 1.39 atm. Assuming ideal behavior, how many grams of acetylene are in the tank?

Predict if a reaction would occur when solutions of 0.1 M Al (NO3) 3 and 0.1 M KI are combined. Explain your reasoning, and, if you predict a reaction will occur, include the net ionic equation for the reaction.

What is the product if an atom of Po-209 undergoes alpha decay?

The first-order decomposition of n2o at 1000 k has a rate constant of 0.76 s-1. if the initial concentration of n2o is 10.9 m, what is the concentration of n2o after 9.6 s

When a catalyst lowers the activation energy of a reaction the rate of the reaction?

Liquids: A) must be contained to stay in one spot B) have a variable volume, but a fixed mass C) are usually more dense than solids and gases D) cannot be changed into gases

Given the following list from the activity series of metals (from most active to least active) K, Na, Al, Mn, Cr, Cd, Co, Pb, Hg which reaction would you NOT expect to occur? 1. Co²⁺ (aq) + Al (s) → Al³⁺ (aq) + Co (s) 2.