Chemical Reactions

True or False
In a chemical reaction, no new atoms are created, and no atoms are destroyed. 

• true
• false

Tags

NGSS.MS-PS1-5

A chemical change is different than a physical change because in a chemical change

• Chemicals are used
• Molecules do not physically touch
• A new substance is formed and in a physical change no new substance is formed
• The change can be seen but in a physical change it cannot

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The left side of the equation below is called

• Products
• Reactants

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

The right side of the equation below is called the

• products
• reactants

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which statement is not a description of a chemical reaction?

• A solid is dropped into a beaker of liquid and a gas is released.
• Two liquids are mixed in a beaker and a solid forms at the bottom of the beaker.
• A solid is dropped into a beaker of liquid and an explosion occurs.
• A liquid is heated in the sun and half of it evaporates.

Tags

NGSS.MS-PS1-2

A number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction.

• Coefficient
• reactant
• subscript
• product 

Tags

NGSS.MS-PS1-5

A chemical reaction that absorbs heat

• Single replacement
• Exothermic
• Endothermic
• Decomposition

Tags

NGSS.MS-PS1-4

NGSS.MS-PS1-6

Which of the following is NOT a sign of a chemical reaction? 

• Color changes
• Cutting into fourths
• Light is produced
• Gas is formed

Tags

NGSS.MS-PS1-2

In a chemical reaction

• The atoms of the reactants always stay together to form the products
• The atoms of the reactants unbond, rearrange, and then rebond to form the products
• New atoms are formed which combine to make the products
• Some atoms disappear while others multiply to form the products

Tags

NGSS.MS-PS1-5

Which of the following is a chemical change rather than a physical change 

• boiling water at 100 C
• chopping up a piece of wood. 
• cooking a cake 
• ice carbon dioxide sublimating to gas 

Tags

NGSS.MS-PS1-2