Balancing Chemical Reactions Practice

Is the following equation balanced or unbalanced ? 
N₂ +3 H₂ --> 2NH₃

• Balanced

• Unbalanced

Answer explanation

The equation N2 + 3 H2 -> 2NH3 is balanced because there are equal numbers of each type of atom on both sides: 2 nitrogen and 6 hydrogen atoms. Thus, the correct choice is 'Balanced'.

Tags

NGSS.MS-PS1-5

What does the :aw of Conservation of Mass tell us about chemical reactions?

• It tells us we never gain or lose atoms in reactions.

• It explains the periodic table.

• It defines the atomic theory.

• It outlines the law of motion.

Answer explanation

The Law of Conservation of Mass states that in a chemical reaction, atoms are neither created nor destroyed. This means we never gain or lose atoms, which is why the correct answer is that we never gain or lose atoms in reactions.

Tags

NGSS.MS-PS1-5

What does this balanced chemical equation tell us about the total number of atoms?

• It indicates the total number of atoms is constant.

• It shows the total number of atoms is variable.

• It suggests the total number of atoms is increasing.

• It implies the total number of atoms is decreasing.

Answer explanation

The balanced chemical equation shows that the number of atoms on the reactant side equals the number on the product side, indicating that the total number of atoms is constant throughout the reaction.

Tags

NGSS.MS-PS1-5

4 grams of hydrogen and 32 grams of oxygen will combine to form:

• 36 grams of water

• 28 grams of hydroxide

• 32 grams of oxygen

• 36 grams of deuterium

Answer explanation

4 grams of hydrogen and 32 grams of oxygen combine in a 2:16 ratio to form water (H2O). The total mass of water produced is 36 grams, confirming that the correct answer is 36 grams of water.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5

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

• Products

• Coefficients

• Precipitates

• Reactants

Answer explanation

In a chemical equation, the substances on the left side are called reactants. They undergo a chemical change to form products, which are listed on the right side. Therefore, the correct answer is reactants.

Is the following equation balanced or unbalanced ? 
Al + O₂ --> Al₂O₃

• Balanced

• Unbalanced

Answer explanation

The equation Al + O2 -> Al2O3 is unbalanced because there are 2 aluminum (Al) atoms and 3 oxygen (O) atoms in Al2O3, while the reactants have only 1 Al and 2 O. Therefore, the correct choice is 'Unbalanced'.

Tags

NGSS.MS-PS1-5

Balance the equation below

_C + _H₂O → _CH₄ + _CO₂

Write the coefficients in order of the equation with a comma separating each number. You should have 4 numbers typed.

_{Note: Write the coefficient "1" to avoid ambiguity}

Tags

NGSS.MS-PS1-5

Which of the following choices gives the correct coefficients of the chemical equation, _Al + _O₂ → _ Al₂O₃ respectively?

• 2,2,2

• 2,3,2

• 4,2,2

• 4,3,2

Balance this equation

_ Zn + _ HCl → _ ZnCl₂ + _ H₂

Write the coefficients in order of the equation with a comma separating each number. You should have 4 numbers typed.

Note: Write the coefficient "1" to avoid ambiguity

Tags

NGSS.MS-PS1-5

Balance this equation

_ C₅H₁₂ + _ O₂ → _ CO₂ + _ H₂O

Write the coefficients in order of the equation with a comma separating each number. You should have 4 numbers typed.

Note: Write the coefficient "1" to avoid ambiguity

Tags

NGSS.MS-PS1-5