Chemical Reactions

Coal contains carbon and other elements. Carbon dioxide forms when coal burns in the presence of oxygen. Which of these is the best evidence that a chemical reaction occurs when coal burns?

• The shape of the coal changes

• Oxygen is present

• A new substance is produced

• Coal is made up of more than one element

Tags

NGSS.MS-PS1-2

All of the following reactions are correctly balanced except-

• A

• B

• C

• D

Tags

NGSS.HS-PS1-7

Which of the following BEST describes a chemical reaction?

• A compound is crushed into a fine powder.

• Atoms break apart into even smaller particles.

• Existing chemical bonds break and new bonds form

• Molecules move faster until they fly apart from each other

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

2 H₂O₂ ---> 2H₂O + O₂

• decomposition

• synthesis

• single replacement

• double replacement

4 Fe + 3O₂ ---> 2 Fe₂O₃

• decomposition

• combustion

• synthesis

• single replacement

2 MgO ----> 2 Mg + O₂

• synthesis

• single replacement

• combustion

• decomposition

Tags

NGSS.MS-PS1-2

2 Al + 3 CuCl₂ ----> 3 Cu + 2 AlCl₃

• combustion

• synthesis

• double replacement

• single replacement

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

AgNO₃ + NaCl ---> AgCl + NaNO₃

• double replacement

• single replacement

• combustion

• decompostion

Tags

NGSS.HS-PS1-2

C₃H₈ + 5 O₂ ---> 3 CO₂ + 4 H₂O

• single replacement

• double replacement

• combustion

• decomposition