Chemical Reactions

What do all chemical changes have in common?

• Energy is absorbed and it feels cold.

• Energy is released and it feels hot.

• Gas bubbles are produced.

• New substances form.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A teacher tells students to describe the physical properties of 10 mL of vinegar and 10 mL of milk. The teacher then pours the vinegar and milk into the same beaker. The students are surprised to see a white solid substance form within the beaker as the two substances are combined. What occurs within the beaker as the teacher mixes the vinegar and milk?

• A physical change that creates a new substance.

• A physical combination that produces a solid.

• A chemical change that produces a precipitate.

• A corrosive reaction between two liquids.

Tags

NGSS.MS-PS1-2

Marie has a balloon with a small amount of baking soda in it. She fits the open end of the balloon over a graduated cylinder containing some vinegar. As she lifts the end of the balloon the baking soda pours into the vinegar causing bubbling and fizzing to occur. Marie observes the balloon began to "fill" up. Based on these observations, which of these can Marie determine about the new substance formed by mixing baking soda with vinegar?

• only a physical change occurred.

• a chemical reaction occurred producing a gas.

• a chemical reaction occurred producing a solid.

• no chemical reaction took place.

Tags

NGSS.MS-PS1-2

A teacher fills a bottle half-full of vinegar. He places baking soda in a paper napkin tied to a rubber stopper. When he shakes the bottle, the vinegar reacts with the baking soda producing bubbles. When the bubbles fill the bottle, the stopper is forced off the top of the bottle. Why does this happen?

• The gas created in the reaction takes up more room than the space in the bottle.

• The temperature of the bottle changes which makes the stopper become too loose.

• The string, napkin, and stopper make the reaction happen too fast.

• There is too much vinegar left in the bottle.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What type of reaction involves the breaking down of a substance into simpler substances?

• Single Displacement Reaction

• Double Displacement Reaction

• Synthesis Reaction

• Decomposition Reaction

A copper penny turning greenish after a few years is an example of ...

• Chemical Change

• Physical Change

Tags

NGSS.MS-PS1-2

A student has two clear liquids, Liquid A and Liquid B. One beaker is filled with Liquid A and Liquid B is added drop by drop. The student recorded the data shown in the table below. What conclusion can be drawn from her observations?

• A precipitate formed

• Temperature increased

• Color changed

• Mass increased

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

At a cold football game, Robert uses an instant hand-warmer to keep his hands warm. He shakes the hand-warmer to mix the two chemicals inside the pouch which instantly releases heat. What evidence indicates that a chemical change has occurred?

• The contents in the hand-warmer melted.

• The contents in the hand-warmer dissolved.

• The contents in the hand-warmer changed temperature.

• The contents in the hand-warmer mixed.

Tags

NGSS.MS-PS1-2

A student has two clear liquids, Liquid A and Liquid B.  One beaker is filled with Liquid A and Liquid B
is added drop by drop.  The student recorded data from her observations in the table below. What evidence that a chemical change has occurred can be found in her observations? Select TWO correct answers

• 1. A precipitate formed

• 1. Temperature increased

• 1. Color changed

• 1. Mass increased

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

During a lab investigation, students followed this procedure:

Students observed bubbles immediately forming around the chalk. After the bubbles stopped forming, the students noticed that the chalk was smaller. Some students tried to recover the missing chalk from the vinegar, but no chalk particles were visible. 

What kind of change did the chalk undergo AND what evidence could be used to support the answer?

Answer explanation

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5