Chemical Changes in Matter

A change in which one or more substances are converted into new substances is a _______. (SC.8.P.9.2)

• . physical change

• nuclear reaction

• chemical change

• chemical fusion

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following best describes how chemical changes differ from physical changes? (SC.8.P.9.2)

• Physical changes produce no new substances and chemical changes do.

• Physical changes always involve the formation of a gas while chemical changes may not.

• Physical changes can occur inside or outside the substance; chemical changes always occur outside.

• Physical changes involve a change of state; chemical changes involve a change of shape.

Jenna wants to paint her room light purple. She makes a mixture of 70% pink paint and 30% blue paint to create the shade she likes. Which of the following best describes what occurs when she mixes the paint? (SC.8.P.9.2)

• An energy change occurs as the paint's chemical properties change.

• A phase change occurs, allowing the two colors to mix evenly together.

• A chemical change occurs as the different color particles react with each other.

• A physical change occurs, since only the physical properties of the paint change.

Joey is performing an experiment in science class. He mixes two liquids in a test tube, and gas bubbles appear at the surface of the test tube. What type of changes are most likely taking place? How do you know? (SC.8.P.9.2)

• Physical change because you can separate the mixture

• Physical change because it still is a liquid

• Chemical change because he used chemicals

• Chemical change because a gas formed.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A physical change does not involve a change in the substance’s chemical identity. Which of these statements describes a physical change? (SC.8.P.9.2)

• A banana starts to smell as it ripens

• Copper turns green when exposed to air

• Onions taste sweeter after being cooked

• Aluminum cans get crushed before recycling

Carbon and Oxygen react to form Carbon Dioxide. What are the reactants? (SC.8.P.9.1)

• Carbon and Dioxide

• Oxygen and Carbon

• Oxygen and Dioxide

• CO₂

Tags

NGSS.MS-PS1-2

When 16 grams of Tin and Hydrogen Fluoride react, they must produce how many grams of product? (SC.8.P.9.1)

• 32

• 8

• 20

• 16

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How can the law of conservation of mass apply to a burning log, if all that remains of it is ash? (SC.8.P.9.1)

• The ash has the same mass as the log, although a large percentage of it blows away

• The law of conservation of mass applies to changes of state but not to chemical

  reactions

• The law of conservation of mass applies to substitution and displacement reactions but not to combustion reactions.

• The masses of the gases and water vapor released into the air by the reaction, plus the

  ash, equal the mass of the log before burning.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

During a chemical reaction, matter cannot be __________ or created. (SC.8.P.9.1)

• Changed

• Destroyed

• Created

• Moved

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NGSS.MS-PS1-5

How does the chemical equation (below) for photosynthesis shown below demonstrate the law of conservation of mass? (SC.8.P.9.1)

 6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂

• The same number of atoms of each element are present both before and after the chemical reaction.

• The same number of each kind of molecule is present both before and after the chemical reaction.

• The same amount of water is present both before and after the chemical reaction.

• The same amount of glucose (C₆H₁₂O₆) is present both before and after the chemical reaction.

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NGSS.MS-PS1-5