Sign and symptoms of a Chemical Change

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

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.
• The mass of the combined liquids is greater than either original liquid.

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

Marie had a beaker with a small amount of baking soda. She added a few drops of pickle juice to the baking soda and observed fizzing and bubbling. Based on her observation, which of these can Marie determine about the new substance formed by mixing the baking soda and pickle juice?

• A chemical reaction produced a solid.
• A chemical reaction produced a gas.
• No chemical reaction took place.
• Only a physical change happened.

Tags

NGSS.MS-PS1-2

The Best Friend's Club uses "invisible ink" to write notes to each other. The invisible ink is actually lemon juice that is clear when it dries on paper, but turns brown when a club member holds a burning candle under the paper. Once it is heated, it is never invisible again.
 What type of change is occurring when the paper is heated?

• chemical change
• elemental change
• physical change
• temperature change

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

Evidence of a physical change.

• New substance
• Shape Change
• Light produced
• Gas released.

Tags

NGSS.MS-PS1-4