8.6B, 8.6E, 6.7B, 8.7A, 8.7B Mastery Bell Ringer

A student places a shiny silver spoon into a solution and observes black tarnish form on the surface. What conclusion can the student make?

• A chemical change occurred due to oxidation.

• A physical change occurred because the color changed.

• The mass of the spoon has increased due to condensation.

• No reaction occurred because the shape of the spoon stayed the same.

Tags

NGSS.MS-PS1-2

During an investigation, a student combines two substances and the container becomes cold. What type of chemical evidence is this, and what does it suggest?

• Temperature change, suggesting an endothermic reaction

• Precipitate formation, suggesting a physical reaction

• Gas production, suggesting combustion

• Color change, suggesting a phase change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS3-4

A teacher asks students to explain how fizzing, color change, and heat release support the idea of a chemical reaction. Which explanation shows the best understanding?

• These signs show that matter rearranged and formed new substances with different properties.

• These signs prove that atoms were destroyed and new ones formed.

• These signs are only possible when substances change state from solid to liquid.

• These signs suggest evaporation has occurred in the system.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

In a closed system, a reaction between baking soda and vinegar produces bubbles. If the reactants weigh 50 g total before the reaction, what will the mass of the products be after?

• Less than 50 g

• More than 50 g

• Exactly 50 g

• Depends on how much vinegar is used

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student burns a piece of paper in an open container. The ashes left behind weigh less than the original paper. How does this relate to the law of conservation of mass?

• Mass is conserved; gases released during the reaction left the open system.

• Mass decreased because some matter was destroyed by the fire.

• Mass increased due to energy produced.

• Mass was only conserved in the ashes, not the gases.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which explanation best supports why balancing chemical equations is necessary?

• It shows atoms are rearranged but not lost or gained during a reaction.

• It ensures the reaction produces enough heat.

• It tells you which reactant is the most important.

• It explains how to calculate the boiling point of a compound.

Tags

NGSS.MS-PS1-5

Two students push on opposite sides of a box: one with 60 N left, and the other with 40 N right. What is the net force and motion of the box?

• 20 N left, the box moves left

• 20 N right, the box moves right

• 100 N total, no motion

• Balanced forces, no motion

Tags

NGSS.MS-PS2-2

A car is moving at a constant speed on a highway. What does this tell you about the forces acting on the car?

• They are balanced—net force is zero.

• They are unbalanced—the car is accelerating.

• The frictional force is greater than the engine force.

• There are no forces acting on the car.

A sled is at rest. A student applies a force of 30 N forward, and friction opposes with 10 N. What happens?

• The sled accelerates because the forces are unbalanced.

• The sled remains still because the forces are balanced.

• The sled moves backward due to friction.

• The sled moves at constant speed with no acceleration.

Tags

NGSS.MS-PS2-2

A 2 kg cart accelerates at 3 m/s². What net force is acting on the cart?

• 1.5 N

• 5 N

• 6 N

• 12 N

Tags

NGSS.MS-PS2-2