Unit 3 Lesson 2 Chemical Equations

When paper is burned, the mass of the remaining ash is less than the mass of the original paper. Which statement best explains this result?

Choose the correct answer.

• The ash has less volume than the paper.

• Some of the matter is destroyed during the reaction.

• The mass of the ash cannot be accurately determined.

• Some of the products of the reaction were given off as a gas.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Ethane (C₂H₆) is one of many compounds that burns in oxygen to form carbon dioxide and water, as represented by the equation.

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Which of the following is a product?

• carbon (C)

• oxygen (O₂)

• water (H₂O)

• ethane (C₂H₆)

Tags

NGSS.MS-PS1-5

Solid magnesium, Mg, reacts with oxygen gas, O₂, to form the solid magnesium oxide, MgO. Which is a balanced chemical equation for this reaction?

Choose the correct answer.

• Mg + O → MgO

• Mg + O2 → MgO₂

• Mg + 2O → 2MgO

• 2Mg + O₂ → 2MgO

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

When coal is burned, sulfur is released into the air, where it reacts with oxygen to produce sulfur dioxide and sulfur trioxide. Which of these is true of this process?

Choose the correct answer.

• The identity of each reactant remains the same.

• Sulfur dioxide and sulfur trioxide are the reactants in this change.

• The products have different chemical properties than those of the reactants.

• The products contain more sulfur atoms and fewer oxygen atoms than the reactants.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which number completes the balanced chemical equation showing the process of rusting?

4Fe + 3O₂ → ___Fe₂O₃

• 1

• 2

• 4

• 12

Tags

NGSS.MS-PS1-5

The chemical formula for hydrogen peroxide is H₂O₂.

What do the letters and numbers in the chemical formula represent.

• 2 Hydrogen atoms and 2 Oxygen atoms

• 1 Hydrogen atom and 1 Oxygen atom

Tags

NGSS.MS-PS1-1

During photosynthesis, water and carbon dioxide react to form oxygen and glucose.

Which are the reactants, which are the products?

• Reactants Oxygen and Glucose Product Water and Carbon Dioxide

• Reactant Water and Carbon Dioxide Product Oxygen and Glucose

Tags

NGSS.MS-LS1-6

NGSS.MS-LS2-3

The following chemical equations represent three different chemical reactions.

3NaOH + H₃PO₄ → Na₃PO₄ + 3H₂O

2Mg + O₂ → 2MgO

Pb(NO₃)₂ + 2NaI → PbI₂ + 2NaNO₃

_{Which Statement is correct choose the best answer}

• MgO is a reactant in one of the chemical reactions.

• Na₃PO₄ is a product in one of the chemical reactions.

• A total of five oxygen atoms are involved in the first reaction.

• H₃PO₄ shows that three atoms of oxygen are involved in the reaction.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

NGSS.MS-PS1-2

The substances listed on the right side of a chemical equation are the

• Yields
• Reactants
• Products
• Precipitates

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

The substances listed on the left side of a chemical equation are the

• Products
• Coefficients
• Precipitates
• Reactants

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2