Which of the following observations indicate that a chemical reaction has taken place? Select TWO correct answers.

• liquid water evaporating as a result of thermal energy from the sun

• two solutions being mixed together and a solid is formed

• condensation on the window of a house on a cold day

• a sugar cube dissolving after it has been dropped in a glass of water

• gas bubbles forming as a cake is baking in the oven

Tags

NGSS.MS-PS1-2

How can physical and chemical changes be differentiated? Indicate whether the following descriptions represent physical or chemical changes. Cutting a piece of paper in half describes a ______ while burning paper describes a ______.

• physical change; chemical change

• chemical change; physical change

• physical change; physical change

• chemical change; chemical change

Tags

NGSS.MS-PS1-2

During a science class experiment, a teacher places a small amount of sugar in a spoon and heats it over a candle.

Which of the following would be the BEST evidence that a chemical change has taken place?

• A. The sugar turns into a colorless liquid.

• B. The color of the sugar turns black.

• C. The sugar has a change in thermal energy.

• D. The sugar gets larger.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student is making observations during a lab in class. Which of the following observations represents evidence of a chemical change?

• Colorful candy melts and stains a student's hands the color of the candy.

• A student uses their teeth to grind the candy into smaller pieces.

• A student drops candy in boiling water and sees the candy dissolve.

• A student swallows the candy and it is broken down by stomach acid.

Tags

NGSS.MS-PS1-2

Which of the following is the best definition of a chemical change, as described in Part A?

• A. A chemical change occurs when a substance changes its appearance.

• B. A chemical change occurs when a substance or object changes shape.

• C. A chemical change results from a change that causes a new substance to form.

• D. A chemical change results from a change that causes a new shape to form.

Tags

NGSS.MS-PS1-2

What can you determine about the new substance formed by mixing baking soda with vinegar?

• A. The color changed.

• B. An odor was produced.

• D. A light was produced.

• E. A gas was produced.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Complete the following statement by moving the answers to the correct boxes. In a ___ no new substance is formed, but in a ___ a brand new substance is formed.

• In a physical change no new substance is formed, but in a chemical change a brand new substance is formed.

• In a chemical change no new substance is formed, but in a physical change a brand new substance is formed.

• In a physical change a brand new substance is formed, but in a chemical change no new substance is formed.

• In a chemical change a brand new substance is formed, but in a physical change no new substance is formed.

Tags

NGSS.MS-PS1-4

Which of the following are evidence that a chemical reaction has occurred? Select TWO correct answers.

• A. salt dissolving in water

• B. food being chewed into smaller pieces

• C. bubbles forming

• D. a solid forming after two liquids are combined

• E. water evaporating from a beaker

Tags

NGSS.MS-PS1-2

A student is conducting an experiment by mixing two solutions into a beaker and then stirring. Which of the following statements would provide the best evidence that a chemical reaction had occurred? Select TWO correct answers.

• One of the two solutions dissolved when the solutions were mixed.

• A new substance was formed when the two solutions were mixed.

• The temperature of the combined solutions increased when mixed and bubbles formed.

• The two solutions had different densities when mixed.

• Drops of water began to form on the outside of the beaker after a period of time.

Tags

NGSS.MS-PS1-2

Which of the following does NOT indicate a chemical reaction occurred?

• A. A gas being produced

• B. A solid being formed

• C. A change in temperature

• D. Temperature staying the same

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5