Chemistry B-Energy-Assignment/Quiz

What happens to energy when Sally kicks a soccer ball?

Kinetic energy is transferred from the leg to the soccer ball.

Which is the best example of how electromagnetic energy is used in everyday life?

a patient receiving an X-ray in a hospital

Which statement is correct about the law of conservation of energy?

Energy is transferred when atoms are rearranged.

Chemical energy in burning wood is changed into thermal energy. The thermal energy is absorbed by water, which boils to produce steam. The thermal energy is changed into kinetic energy in the moving steam. The kinetic energy is used to turn a turbine, which converts the kinetic energy into electricity. Which sentence best describes this system?

It involves both energy transformation and energy transfer.

A book is falling from the top shelf of a bookcase. Which statement correctly describes the change in the energy of the book?

The potential energy decreases as kinetic energy increases

Consider the following generic chemical equation: A + B → C + D Reactant A contains 85.1 J of chemical energy. Reactant B contains 87.9 J of chemical energy. Product C contains 38.7 J of chemical energy. If the reaction absorbs 104.3 J of chemical energy as it proceeds, how much chemical energy must product D contain? Explain your answer.

The total amount of energy in the reactants, plus the energy absorbed during the reaction

Thermal energy is the energy associated with

temperature.

Describe the energy transfers and transformations that occur when a person rides a bicycle. Make sure to identify each example as an energy transfer or an energy transformation.

A bicycle by itself doesn't use any energy at all, but a human riding a bicycle will be using up chemical energy from the food he's eaten, and turning that into heat and kinetic energy. If the ride takes him up a hill he will also gain potential energy. Chemical energy in the food the rider has eaten turns into kinetic energy. If the rider is heading uphill it gets turned into potential energy as well. Some of it turns into thermal energy in the muscles of the rider, in the tires, and in the bearings. Chemical energy from what the rider has eaten gets turned into kinetic energy. Energy isn't really produced, only transformed. Chemical energy in the shape of the food the rider has eaten gets turned into kinetic energy as the bike pick up speed, potential energy if the rider heads uphill, and then some heat in muscles, tires, and bearings. When you are riding a bike you are converting chemical energy produced in your muscles to mechanical energy which is then divided between kinetic energy and frictional losses. When you come to a hill you are also gaining gravitational potential energy, which can then be converted to kinetic energy when you coast down the other side. Physical-Mechanical-kinetic. Chemical energy from ingested food is what gets used while riding a bike

Which of these did you include in your answer?

Check all

A generator contains a coil that spins to produce an electric current. How is energy transformed by using a generator?

Mechanical energy is transformed to electromagnetic energy.

A satellite re-enters the earth's atmosphere. It burns and starts to disintegrate because of the intense heat. Which energy transformation is responsible for the satellite's disintegration?

kinetic energy to thermal energy

In a chemical reaction occurring in an open beaker, the reactants have a mass of 10.0 g and contain 1000 J of energy. The products in the beaker contain a mass of 5.0 g and 500 J of energy. Which best explains the difference in energy and mass as reactants are converted to products?

law of conservation

Consider the generic chemical equation below. X + Ymc021-1.jpg W + Z Reactant X contains 199.3 J of chemical energy. Reactant Y contains 272.3 J of chemical energy. Product W contains 41.9 J of chemical energy. If the reaction loses 111.6 J of chemical energy as it proceeds, how much chemical energy must product Z contain?

not C

In a mechanical clock, the swinging of a pendulum causes the hands to move. The diagram shows the path of the pendulum as it swings. At which point in its swing does the pendulum have the least gravitational potential energy?

point C