chemical reactions

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

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

Which of the following describes a precipitate?

• a liquid forms when a block of metal is heated
• a solid forms when one liquid is poured into another
• a gas forms when a solid is placed in a liquid
• bubbles form when an acid is poured on a rock

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

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 of the following is an example that includes evidence of a chemical reaction?

• A sample of zinc is placed in water and it settles to the bottom
• A solid block of ice is heated and it completely melts into a liquid. 
• Sugar that is burned gives off an odor and turns brown and then black.
• A tomato is placed into a blender and chopped up into smaller pieces.

Tags

NGSS.MS-PS1-2

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

Dissolving salt is a

• Chemical change

• Physical change

Tags

NGSS.MS-PS1-2

The glow stick reaction is a

• Chemical change

• Physical change

Tags

NGSS.MS-PS1-2

The production of carbon dioxide gas when baking soda and vinegar reacted indicated a _____________.

• Chemical change

• Physical change

Tags

NGSS.MS-PS1-2