Ammonia reacts with oxygen to produce nitrogen and water according to the equation below. What is the enthalpy of the reaction?

Which of the following is an example of how a scientist might use a model? A. a wrench is used to tighten a nut onto a piece of wood B. marbles placed onto a hollow sphere are used to describe protons in a nucleus C.

What happens when a oceanic crust and a continent crust collide? What forms? Which is more denser? What type of boundary?

How many paired electrons are in the lewis structure of lithium nitride?

Aluminum plus chlorine yields aluminum chloride

Which type of heat transfer involves the movement of warmed material? A. radiation B. conduction C. convection

Is a sample of liquid nitrogen more dense than a sample of nitrogen gas

You have a balloon containing 1 L of air at STP in a vacuum chamber. What will the volume of the balloon be when you reduce the pressure by half and increase the temperature to 373 K?

Which method will correctly determine whether the forces on an object are balanced or unbalanced? A. Multiply the forces in the horizontal direction by the forces in the vertical direction. B.

Carbon is found in all known forms of life. Which statement best describes why carbon is uniquely suited to forming macromolecules such as those found in living organisms? A. Carbon forms large compounds that are not chemically reactive. B.

Name a type of asteroid and give a description.