A substance that speeds up the rate of a chemical reaction is called

a. a catalyst

b. a substrate.

c. an enzyme.

d. Both A and C

One difference between a chemical reaction and a nuclear reaction is that in a nuclear reaction: a) atoms retain their identity. b) only the valence electrons are involved. c) atoms often change from one element to another.

Which of the following is correctly abbreviated SI unit describing the mass of an object? A) kg B) mol C) m D) M

If body fats has a density of 0.94 g/mL and 3.0 liters of fat are removed, how many pounds of fat were removed from the patient?

What is the molecularity of the elementary step A + B + C? O A. unimolecular OB. bimolecular O C. trimolecular OD tetramolecular

What is the number of moles of 500 liters of He gas at STP? A) 0.2 mol B) 90 mol C) 0.05 mol D) 22 mol

The balanced equation below represents the reaction between magnesium metal and hydrochloric acid to produce aqueous magnesium chloride and hydrogen gas. Mg (s) + 2HCl (aq) = = > MgCl2 (aq) + H2 (g) A piece of Mg (s) has a volume of 0.

What is the molarity of a solution prepared by dissolving 33.4 g of sodium chloride in some water and then diluting the solution to a volume of 300.00 mL?

Think about how pressure relates to volume and how gas behavior would change in different volumes. Which of the following will have the largest positive value for Sº? A) 1 mole of helium gas at 1 atm pressure.

Does a reaction stop once it has reached equilibrium? Explain

8 l of water at 19 ∘c are mixed with 1.1 l of water at 47 ∘c in an insulated container. what is the final temperature of the system? express your answer in ∘c