Chemical Reactions

In a ___________change, a substance changes into a different substance.

• Physical
• Chemical

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of these is NOT a sign that a chemical change has occurred? 

• A loss of transparency 
• An unexpected color change
• A temperature change
• The formation of a precipitate

Tags

NGSS.MS-PS1-2

In a chemical reaction, bonds are broken and new bonds are formed that create new substances. The bonds that are broken are called what?

• Reactants
• Products
• Atoms
• Catalysts

A (n) ________________ reaction releases energy and temperature usually increases

• endothermic
• radioactive
• exothermic
• physical

Tags

NGSS.HS-PS1-4

The Law of Conservation of Mass states

• that matter exists in all states and reacts the same
• that matter can only be changed into new substances by introducing a catalyst
• that matter exists in the same state throughout any chemical change
• that matter cannot be created or destroyed and that the mass of the products must equal the mass of the reactants

Tags

NGSS.HS-PS1-7

A reaction that occurs when two or more elements or compounds combine to make a more complex substance is called

• double replacement
• decomposition
• synthesis
• single replacement

Balance this equation: ___ Cl₂ + ___ KI → ___ KCl + ___ I₂

• ___ Cl₂ + ___ KI → ___ KCl + 2 I₂
• 2 Cl₂ + ___ KI → ___ KCl₂ + ___ I₂
• ___ Cl₂ + 2 KI → 2 KCl + ___ I₂

Tags

NGSS.HS-PS1-7

A ___________reaction absorbs energy and is usually accompanied by a decrease in temperature.

• exothermic
• combustion
• endothermic
• synthesis

Tags

NGSS.HS-PS1-4

A ___________ takes part in a chemical reaction but is not consumed

• reactant
• catalyst
• product
• nucleus

Balance this equation:  H₂ +  N₂ →  NH₃

•  H₂ +  4N₂ →  NH₃
•  H₂ +  3N₂ →  2NH₃
•  3H₂ +  N₂ →  2NH₃
•  2H₂ + 2N₂ → 2NH₃

Tags

NGSS.MS-PS1-5