What must happen before a chemical reaction can begin?

a the activation energy must be exceeded.
b the activation energy must be reached.
c the concentrations of products and reactants must be equal.
d the concentration of reactant molecules must be reduced.

Select the correct text in the passage. which sentences describe examples of sustainable living? i live in an old apartment building downtown, but my company is based in an office park on the outskirts of the city. i drive an old car that needs to be replaced. i plan to buy a hybrid for better gas mileage, but for now i am able to carpool with a couple of friends from work. the drive to the office park is about 45 minutes each way, but we do get to work in a modern building. the architects just received a leed certification for the design.

If blood contains 150g of hemoglobin per liter of blood, how much hemoglobin would be contained in 10 ml of blood

Identify arrows pointing to bonding electrons. done h-0-0-h ) intro