Question

Fill in the blanks with the given words.

In the last 40 years, the concentration of carbon dioxide in the air has increased by more than 20%. IR spectroscopy shows that carbon dioxide absorbs IR radiation.

If carbon dioxide molecules absorb IR radiation, where does that energy go? How does the increase in the concentration of carbon dioxide affect the air temperature?

If carbon dioxide molecules absorb IR radiation, the energy goes into( ___). Vibrating carbon dioxide molecules make other molecules in the air move faster. This means that the average (___)energy of the air molecules(___)and therefore the air temperature(___). Since the concentration of carbon dioxide has increased in the last 40 years, ( ___)IR radian is now absorbed leading to(___)temperatures.

Answer bank: higher, lower, potential, kinetic, increases, decreases, less, more, bond breaking, rotational motion, vibrational motion

Answer 1

If carbon dioxide molecules absorb IR radiation, the energy goes into( _1_). Vibrating carbon dioxide molecules make other molecules in the air move faster. This means that the average (__2_)energy of the air molecules(_3__)and therefore the air temperature(_4__). Since the concentration of carbon dioxide has increased in the last 40 years, ( _5__)IR radian is now absorbed leading to(_6__)temperatures.

1. Vibration motion.

Since, the center idea of the paragraph is about energy absorption, on absorbing IR radiation, the energy must go into the vibration and rotation motion of the molecule, or more plausibly the energy would go into changing the vibration energy level and rotation energy levels of the molecule. But reading the whole paragraph gives an idea that the vibration of the molecule is being talked about here, so, we would go with Vibration motion.

2. Kinetic

Since, we are taking about motion, we would go with kinetic energy because the form of energy associated with motion is kinetic energy. Moreover, potential energy is often reffered to when something is at rest, and this is converted to kinetic energy when something is in motion.

3. Increases

As the absorption of energy is the premise of this paragraph, the kinetic energy would increase on absorption of energy. For example, say E was the kinetic energy of a molecule before any IR radiation was absorbed. Now, say e is the magnitude of the energy that has been absorbed, so the total energy after absorption of e energy becomes (E+e).

4. Increases

Since the kinetic energy is increased, the energy from increased vibration motion would dissipate in form of thermal energy, this would result in a increase of the temperature.

5. Higher

Let's say a single molecule was absorbing certain amount of IR radiation, now since the concentration of carbon dioxide molecule has increased in the last 40 years, this would result in the higher IR radiation absorption.

6. Higher

Since, the IR absorption has increased due to the increase in the concentration of carbon dioxide, as discussed earlier, the temperature would also increase.