Chemical/Phys. Reaction + Signs + Atom Counting

When a physical change happens, the form changes, but the ______ doesn't.

• size

• shape

• molecular structure

When a chemical reaction happens, _______ .

• the size of the sample changes

• new molecules are made

• sample melts, freezes, or evaporates

Tags

NGSS.MS-PS1-2

Which 2 are examples of a physical changes? (check 2 )

• ice melting

• sodium and chlorine combining to make sodium chloride (salt)

• paper being cut into smaller pieces

• wood burning

Which 2 are examples of a chemical changes? (check 2 )

• ice melting

• sodium and chlorine combining to make sodium chloride (salt)

• paper being cut into smaller pieces

• wood burning

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which are 2 signs that a chemical reaction has happened? (check 2)

• color changes

• temperature changes (up or down)

• form changes (freezing, melting, evaporating)

Tags

NGSS.MS-PS1-2

Which are 2 signs that a chemical reaction has happened? (check 2)

• a powdery precipitate forms

• the pieces get smaller

• fire is created

Tags

NGSS.MS-PS1-2

This picture shows which sign that a chemical reaction happened?

• a powdery precipitate formed

• the temperature dropped

• energy changed (light and flames are produced)

Tags

NGSS.MS-PS1-2

This pictures shows which sign that a chemical reaction happened?

• a powdery precipitate formed

• the temperature dropped

• energy changed

Tags

NGSS.MS-PS1-2

This picture shows which sign that a chemical reaction happened?

• color changed

• the temperature dropped

• energy changed (light and flames are produced)

Tags

NGSS.MS-PS1-2

If the temperature drops as a reaction happens, it is a ______________ reaction.

• Endothermic

• Exothermic

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4