Chemical Reactions

Which equation below demonstrates the law of conservation of mass?

• Mg + S --> MgS₂

• C + O₂ --> C₂O

• 4Cu + O₂ --> 2Cu₂O

• H₂SO₄ + Zn --> 4ZnSO + H₂

Tags

NGSS.MS-PS1-5

What type of reaction is displayed below?

2KClO₃ --> 2KCl + 3O₂

• synthesis

• decomposition

• single replacement

• double replacement

Chemical equations must be balanced because

• the mass of the reactants is always greater than the mass of the products

• the mass of the products is always greater than the mass of the reactants

• mass can neither be created nor destroyed

• mass is determined by a chemical reaction

Tags

NGSS.MS-PS1-5

Which equation correctly illustrates conservation of mass?

• 
• 
• 
• 

Tags

NGSS.MS-PS1-5

Look at the following chemical equation

4Al + 3O₂ --> 2Al₂O₃

What is true about this chemical equation?

• The products contain the same numbers and types of atoms as the reactants.

• The products contain the same arrangement of atoms as found in the reactants.

• The products contain the same numbers but not the same types of atoms as the reactants.

• The products contain the same types but not the same numbers of atoms as the reactants.

Tags

NGSS.MS-PS1-5

Look at the following equation

__Au₂O₃ --> __Au + __ O₂

In order to follow the law of conservation of mass, this equation must have which set of coefficients, in order from left to right?

• 2, 4, 3

• 1, 2, 1

• 2, 1, 3

• 1, 1, 3

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The balanced chemical equation below shows the reaction between nitrogen (N₂) and hydrogen (H₂) to form ammonia (NH₃)

N₂ + 3H₂ --> 2NH₃

If 15.0 grams of nitrogen is reacted to produce 40.0 grams of ammonia, how many grams of hydrogen were used?

• 15 g

• 25 g

• 10 g

• 55 g

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

If the chemical equation below is balanced, what number would go in front of oxygen (O2)?

• 4

• 6

• 3

• 9

Tags

NGSS.MS-PS1-5

If the chemical equation below is balanced, what number would go in front of HClO3?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-5

The equation shows an unbalanced chemical reaction. What are the missing coefficients that are needed to make this equation balanced from left to right?

___Fe + ___O₂ --> ___Fe₂O₃

• 1, 1, 1

• 2, 3, 1

• 2, 3, 2

• 4, 3, 2

Tags

NGSS.MS-PS1-5