Science

Which of these BEST describes the motion of atoms in solid iron as it melts? (Lesson 3)

• The atoms slow down and gather together

• The atoms speed up and move past one another.

• The atoms vibrate in place but cannot move past one another

• The atoms are separated from their electrons, leaving the electrons negatively charged.

Tags

NGSS.MS-PS1-4

The diagram is a representation of the periodic table. The letters A through D represent four element. Which letter represents the element with the MOST protons? (lesson 2)

• A

• B

• C

• D

Tags

NGSS.MS-PS1-1

Sulfur, bromine, and argon are nonmetal elements. At room temperature, sulfur is a solid, bromine is a liquid, and argon is a gas. Which statement about these elements is true? (Lesson 3)

• Bromine has a lower melting point than either sulfur or argon.

• Sulfur has a lower melting point than either bromine or argon.

• Sulfur has a higher melting point than either bromine or argon

• Argon has a higher melting point than either bromine or sulfur.

The chemical equation shows how solid potassium (K) and chlorine gas (Cl₂) combine to form potassium chloride (KCl)

A scientist mixes 78 grams of potassium with 71 grams of chlorine gas. How much potassium chloride can the scientist expect to be produced? (Lesson 5)

• 7 grams

• 71 grams

• 78 grams

• 149 grams

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of these represents an element? (Lesson 1)

• Pb

• PbS

• CO₂

• NaCl

Which of these is the BEST evidence that a substance has undergone a chemical change? (Lesson 4)

• The substance has released light.

• The shape of the substance has changed.

• The density of the substance has changed.

• The temperature of the substance has decreased.

Tags

NGSS.MS-PS1-2

A student pours a teaspoon of salt into a glass of water. The student stirs the water until the salt dissolves completely. Afterward, the student cannot see the salt in the water. What kind of substance has the student made? (Lesson 1)

• an element

• a compound

• a homogeneous mixture

• a heterogeneous mixture

The chemical equation shows how nickel oxide (Ni₂O₃) changes into nickel atoms (Ni) and oxygen molecules (O₂). How many total atoms of nickel are involved in this reaction? (Lesson 5)

• 2

• 4

• 8

• 9

Tags

NGSS.MS-PS1-5

The boiling point of nitrogen is -196°C. The melting point of nitrogen is -210°C. At which temperature does nitrogen MOST LIKELY condense, or change from a gas to a liquid? (Lesson 3)

• -14°C

• -196°C

• -210°C

• -406°C

Tags

NGSS.MS-PS1-4

Which situation involves a precipitate forming? (Lesson 4)

• Water condenses in clouds and falls to the ground.

• An iron fence outdoors is rained on repeatedly and begins to rust.

• Salt is poured into water, and the water is stirred until the salt dissolves completely.

• Two liquid solutions are mixed together, and a yellow solid forms at the bottom of the container.

Tags

NGSS.MS-PS1-2