Evidence of a Chemical Reaction

Which statement is NOT evidence that a new substance has formed during a chemical reaction?

• Gas is produced

• Temperature changes

• Precipitate forms

• Substance melts

Tags

NGSS.MS-PS1-2

During an investigation, students mix an unknown powder and unknown liquid. When the students pour the liquid into the powder, bubbles are produced. Which statement correctly identifies the type of investigation?

• The powder and liquid repel one another and produces bubbles

• The powder and liquid produce bubbles because the law of conservation of mass is violated

• The powder and liquid produce bubbles because a chemical reaction occurs

• The powder and liquid produce bubbles because a physical change occurs.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

What evidence of chemical reaction will be observed based on this chemical reaction?

• Gas formation

• Flash of light

• Decrease in mass

• Formation of precipitate

Tags

NGSS.MS-PS1-2

The mass remains constant before and after the chemical reaction

• The mass remains constant before and after the chemical reaction

• The mass of the gas is more than the mass of the baking soda, so the mass is constant

• The volume of the products is more than the volume of the reactants, so it does not support the law of conservation of mass

• The density of the products is less than the reactants, so the mass is constant

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following could be the hypothesis supported by an investigation that demonstrates the law of conservation of mass in relation to chemical reactions?

• If the reaction obeys the law of conservation of mass, then mass will be the same before and after the reaction

• If the reaction obeys the law of conservation of mass, then the mass will increase after the reaction

• If the reaction obeys the law of conservation of mass, then the mass will be different before and after the reaction

• If the reaction obeys the law of conservation of mass, then the mass will decrease after the reaction

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which description provides evidence that chemical reactions form new substances with different chemical properties?

• Bubbles formed in a bathtub

• Food coloring added to water

• Butter melted in a pan

• Eggs fried in a skillet

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which investigation results do NOT represent evidence of a chemical reaction?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-2

What evidence of a chemical reaction does the space shuttle exhibit?

• Formation of precipitate

• Emission of light

• Disintegration of the element

• Change of color

Tags

NGSS.MS-PS1-2

You know you a chemical reaction has occurred if 

• there is a precipitate.

• there is a color change.

• there is a temperature change.

• All of these answers are evidence.

Tags

NGSS.MS-PS1-2

A student mixes two clear liquids together. After a few minutes, a white powdery solid can be seen settling on the bottom of the test tube. Which of the following is a conclusion that the student can draw based on these observations? The two clear liquids-

• were pure substances before they were mixed

• are toxic and should be handled with extreme caution

• have gone through a chemical change in which a new substance called a precipitate was produced

• have been stored too long and are no longer good

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5