8th Grade Science / Structure and Properties of Matter

Magnesium (Mg) is a grayish-white metal and reacts actively with water. Fluorine (F2) is a greenish-yellow gas at room temperature and is a member of the halogen family. These two elements react to produce magnesium fluoride (MgF2), a chemical commonly used in making windows and lenses. How does adding heat energy affect magnesium fluoride (MgF2) molecules?

• The motion of the molecules stops.

• The motion of the molecules increases.

• The motion of the molecules decreases.

• The motion of the molecules is at a constant rate.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Which of the following substances has the lowest average molecular kinetic energy?

• Quartz at 25°C

• Steel at 50°C

• Nitrogen 75°C

• Water at -10°C

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NGSS.MS-PS1-4

A student is shown a simple model of particles that make up a liquid, as shown.

How should the model be changed to show the particles of a liquid at a lower temperature?

• Separate the particles into positive and negative charges, and increase the space between the particles.

• Separate the particles into positive and negative charges, but maintain the same space between the particles.

• Decrease the velocities of the particles, and maintain the space between the particles.

• Increase the velocities of the particles, but increase the same space between the particles.

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NGSS.MS-PS1-4

Which states of matter have particles that move independently of one another with very little attraction?

• Solids

• Liquids

• Gases

• Both solids and liquids

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NGSS.MS-PS1-4

certain substance is a solid at 15°C. Sarah heated a sample of the solid substance in a beaker using a Bunsenburner during science class. She and her partner recorded the temperature at one-minute intervals. Their data isrecorded in the table below. Based on the girls' data, when was the kinetic energy of the substance the greatest?

• 15 °C

• 60 °C

• When they started the heating process.

• During the period when the substance remained at 54 C.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

NGSS.MS-PS3-5

Relate the changes in molecular motion of particles as they change from solid to liquid to gas.

• As the phase changes occur, the freedom of motion of the particles increases.

• As the phase changes occur, the freedom of motion of the particles decreases.

• As the phase changes occur, the freedom of motion of the particles compresses.

• As the phase changes occur, the freedom of motion of the particles is constant.

Tags

NGSS.MS-PS1-4

Based on the data recorded by Sarah and her partner, at which minute did the temperature of the substance first reach 60°C?

• At the 6th minute

• At the 7th minute

• At the 9th minute

• At the 10th minute

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

According to the observations recorded, how are the particles in ice arranged?

• Particles are farther apart than the other two samples.

• Particles have an arrangement that is extremely random.

• Particles are packed together very closely in a three-dimensional square pattern.

• Although the particles are somewhat clumped, they do not appear to be arranged in a recognizable pattern.

What observation was made about the particle arrangement in liquid water?

• Particles are packed together very closely.

• Particles are somewhat clumped and arranged in a recognizable pattern.

• Particles are farther apart than in ice and have an extremely random arrangement.

• Particles are not as tightly packed together as in steam.

Which of the following best describes the particle arrangement in steam according to the observations?

• Particles are packed together very closely.

• Particles are farther apart than the other two samples and arranged in a three-dimensional square pattern.

• Particles are not as tightly packed together as the ice particles and are somewhat clumped.

• Particles have an arrangement that is extremely random.

Tags

NGSS.MS-PS1-4