S8P1 D

When determining whether a chemical reaction has taken place, you observe and look for several indicators. Which would be considered an indication that a chemical reaction or chemical change has taken place?

• Solid melts.

• Heat is given off.

• Substance dissolves

• Substance changes shape.

Tags

NGSS.MS-PS1-2

Which is an example of a physical change?

• Mixing blue and yellow paint to create green paint

• Adding water and yeast to bread dough in order to make it raise.

• Mixing two liquids together in a test tube and the tube becoming warm.

• Adding a piece of chalk containing calcium carbonate to a glass of mild acid causing the formation of a foam of bubbles.

Which test result indicated a chemical change had taken place?

• dissolves in water

• feels slippery in water

• melts when heated in a flame

• turns black when iodine is added

Tags

NGSS.MS-PS1-2

What kind of reaction occurred in the cold pack? What evidence supports your answer?

• It is a physical change as evidenced by a drop in temperature.

• It is a chemical change because two different chemicals are mixed together.

• It is a chemical change because heat energy is absorbed and the pack gets colder.

• It is a physical change because the substance in the vial dissolved in the pack's liquid.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

You and your lab partner take two clear liquids and mix them together. When observing the final product, you notice a yellow solid has formed. What is the term for the solid that is formed as a result of a chemical change?

• condensate

• evaporate

• precipitate

• sublimate

Tags

NGSS.MS-PS1-2

When solid sodium metal is placed in water, energy is released and sparks fly as sodium hydroxide is formed. Which of these best describes this situation? The release of energy is a sign of a ___________ change.

• chemical

• endothermic

• phase

• physical

Tags

NGSS.MS-PS1-2

Maria and Miquel were enjoying the fireworks when they got into a chemistry argument. Maria insisted that the fireworks were the result of a chemical reaction. Miguel disagreed. What would you tell them to solve this argument?

• It is a change of state, solid to gas, due to the addition of energy.

• It was a physical reaction since the fuse was lit and heat was produced.

• The color changes and the release of energy indicate a chemical reaction.

• It is an endothermic reaction because energy was added; therefore it is a chemical reaction,

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

In physical science lab, Ben and Jerry added small pieces of magnesium to hydrochloric acid. They noticed that bubbles formed, the test tube got hot, and the magnesium disappeared. What is a sign that a chemical reaction has taken place in this experiment?

• odor

• gas is produced

• magnesium disappeared

• decrease in temperature

Tags

NGSS.MS-PS1-2

How would you respond to Roger?

• Roger is incorrect. The melting wax is a physical change but there is no chemical change taking place.

• Roger is correct. Lighting the match is a chemical change and burning the candles is a physical change.

• Roger is correct. The melting wax is a physical change and the burning candle wick is a chemical change.

• Roger is incorrect. Only a chemical change is taking place as evidenced by the light and heat of the burning candles.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

NGSS.MS-PS1-5

A student takes four samples of a white crystalline solid and places each in a well plate. On top of each sample, she carefully places 20 drops of clear mystery liquids A, B, C and D. Her results for each well are:

Liquid A: The solid dissolves quickly.

Liquid B: The solid appears unchanged.

Liquid C: A brownish colored liquid is produced.

Liquid D: Fizzing occurs and the well becomes warmer.

In which well does a PHYSICAL change occur?

• A

• B

• C

• D

Tags

NGSS.MS-PS1-2