Chemical Equations and Conservation of Matter

What does a subscript in a chemical formula represent?

• The number of molecules of a compound

• The number of atoms of an element in a molecule

• The total mass of the compound

• The charge of the molecule

In the chemical equation "2H₂ + O₂ → 2H₂O", what does the coefficient "2" in front of H₂ represent?

• The number of hydrogen atoms in the product

• The number of molecules of hydrogen gas reacting

• The number of oxygen molecules reacting

• The number of water molecules produced

Tags

NGSS.MS-PS1-1

Which of the following best explains the law of conservation of matter as demonstrated in a chemical equation?

• Matter is created during a chemical reaction.

• Matter is destroyed during a chemical reaction.

• Matter is neither created nor destroyed, only rearranged.

• Matter is converted into energy during a chemical reaction.

Tags

NGSS.MS-PS1-5

In the equation "Cu₂O₂ + C → 2Cu + CO₂", which of the following are the products of the reaction?

• Cu₂O₂ and C

• Cu and CO₂

• Cu₂O₂ and CO₂

• C and Cu

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

In the equation "2H₂ + O₂ → 2H₂O", how many oxygen atoms are present in the product?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

In the reaction CO + 2H₂ → CH₃OH, what is the role of hydrogen (H₂)?

• Reactant

• Product

• Catalyst

• Byproduct

What is the product formed when nitrogen (N₂) reacts with hydrogen (H₂) in the given chemical equation?

• Ammonia (NH₃)

• Water (H₂O)

• Sodium chloride (NaCl)

• Calcium carbonate (CaCO₃)

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Which of the following is a product of the reaction CaCO₃ + 2HCl → CaCl₂ + H₂CO₃?

• Calcium chloride (CaCl₂)

• Ammonia (NH₃)

• Sodium hydroxide (NaOH)

• Hydrogen gas (H₂)

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

How many molecules of hydrogen (H₂) are required to react with one molecule of nitrogen (N₂) to form ammonia (NH₃) in the given equation?

• 1 molecule

• 2 molecules

• 3 molecules

• 4 molecules

Tags

NGSS.MS-PS1-5

Label the reactants and products in the chemical equation shown.

a

b

Products

Reactants

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-1