Evidence of Chemical reactions 1

A student places a piece of a potato into a container of hydrogen peroxide. One observation the student makes is that bubbles form around the potato. The presence of bubbles might indicate the formation of a new substance because bubbles - 

• could show that a gas is forming
• always rise to the top of a liquid. 
• are almost always perfectly spherical.
• usually burst after a few minutes.

Tags

NGSS.MS-PS1-2

A clear liquid from a flask is poured into another clear liquid in a beaker. Which of the following results of this procedure would indicate a new substance was formed?

• The level of the substance in the beaker is higher after the other liquid is added.
• A yellow solid forms and then settles to the bottom of the beaker.
• Small white crystals are left behind in the flask that held the first liquid.

Tags

NGSS.MS-PS1-2

Evidence of a chemical reactions is anything that shows - 

• a new substance has formed
• a solid dissolved in a liquid
• interaction between 2 gases
• a change in the state of matter

Tags

NGSS.MS-PS1-2

For an investigation a student poured a blue solution of CuSO₄ into a beaker. The student placed a shiny, silver-colored strip of zinc metal in the solution and observed the changes.
The student inferred that a chemical reaction occurred. What evidence supports this inference?

• A dark solid formed on the zinc metal.
• 
  The zinc metal remained silver-colored and shiny
• The CuSO₄ solution turned blue when the zinc metal was added.
• None of these

Tags

NGSS.MS-PS1-2

Which of these formulas contain equal numbers of nitrogen atoms?

• Formulas I and III
• Formulas I and IV
• Formulas II and III
• Formulas I, II, and V

Tags

NGSS.MS-PS1-1

Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?

• The shape of the coal changes
• Oxygen is present
• A new substance is produced
• Coal is made up of more than one element

Tags

NGSS.MS-PS1-2

Which of the following examples shows that a chemical reaction has occurred? 

• A rock breaks into smaller pieces when it is struck with a hammer.
• Rust forms on a hammer that has been left outside to long. 
• A cup of water turns pink when a few drops of red food coloring are added. 
• A solid is formed when heat is removed from a sample of water. 

Tags

NGSS.MS-PS1-2

One of the signs of a chemical reaction taking place is:

• Bubbles are produced 
• Reactants are not combining
• Products are not forming
• Color is not changing

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

Which is NOT an indication of a chemical change?

• temperature change
• formation of a precipitate
• shape change
• production of light

Tags

NGSS.MS-PS1-2