Law of Conservation of Mass

A 500-gram block of solid cheese is melted in a pot. Which is most likely the mass of the cheese after it is melted?

• 500 grams, because the cheese does not gain or lose mass just because it was melted
• 499 grams, because some of the cheese evaporates as it melts
• 502 grams, because the cheese absorbs heat as it melts

A student notices that an inflated balloon gets larger when it is warmed by a lamp. Which best describes the mass of the balloon as a result of this change?

• The mass of the balloon increases because the size of the balloon has increased.
• The mass of the balloon increases because the temperature of the balloon has increased.
• The mass of the balloon stays the same because the gas inside the balloon still has the same mass after it warms up.

What is the Law of Conservation of mass?

• Mass is created in a chemical reaction
• Mass is created in a physical change
• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants
• Mass is never created or destroyed

The rock in the picture is pushed over the edge and it begins to fall. Which type of energy conversion is taking place?

• mechanical to heat

• sound to mechanical

• potential to kinetic

• kinetic to potential

A ball is projected into the air. Where is potential energy the greatest?

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Which point on the roller coaster's path represents the maximum potential energy?

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As a roller coaster goes downhill

• kinetic energy is converted into potential energy.

• potential energy is converted into kinetic energy.

• electrical energy is converted into potential energy.

• potential energy is converted into electrical energy.

When gasoline is burned in a car engine, ________ energy is converted into _________ energy.

• heat, chemical

• chemical, potential

• mechanical, chemical

• chemical, mechanical

Energy is transferred in solids by conduction, which means that

• heat travels in both directions.

• heat travels from the cooler object to the hotter object.

• heat travels from the hotter object to the cooler object.

• heat does not travel between objects of different temperatures.

The light bulb converts electrical energy into light and _________.

• chemical

• electromagnetic

• heat

• nuclear