This video tutorial provides an optional guide for students struggling with balancing chemical equations. It begins with an introduction to the law of conservation of mass, explaining that the total mass of reactants must equal the total mass of products in a chemical reaction. The video then covers the basics of balancing equations, emphasizing the importance of adjusting coefficients while keeping subscripts unchanged. Through practical examples, the tutorial demonstrates how to balance equations by counting atoms and adjusting coefficients. Students are encouraged to practice additional problems independently.

What is the purpose of this optional video?

• To explain the periodic table

• To introduce new chemical concepts

• To provide extra help with balancing equations

• To discuss the history of chemistry

What does the law of conservation of mass state?

• Energy is always conserved

• Atoms can change their identity

• Matter can be created and destroyed

• The total amount of matter remains constant during any change

Tags

NGSS.MS-PS1-5

Why must the total mass of reactants equal the total mass of products in a chemical equation?

• To ensure the reaction is spontaneous

• To make the equation easier to solve

• To follow the law of conservation of energy

• To follow the law of conservation of mass

Tags

NGSS.MS-PS1-5

What can you adjust to balance a chemical equation?

• The state of matter

• The subscripts

• The coefficients

• The chemical symbols

Which numbers in a chemical formula are you not allowed to change when balancing equations?

• Coefficients

• Subscripts

• Atomic numbers

• Molecular weights

In the example with hydrogen and oxygen, what was the initial imbalance?

• Oxygen atoms

• Both hydrogen and oxygen atoms

• Hydrogen atoms

• Neither hydrogen nor oxygen atoms

Tags

NGSS.MS-PS1-2

How do you balance the oxygen atoms in the hydrogen and oxygen example?

• By changing the subscript of oxygen

• By adding a coefficient to water

• By removing hydrogen atoms

• By adding more reactants

Tags

NGSS.MS-PS1-5

What is the final step in balancing the hydrogen and oxygen equation?

• Adjusting the hydrogen atoms

• Adjusting the oxygen atoms

• Changing the subscripts

• Adding more products

In the complex example with phosphorus and oxygen, what was the initial imbalance?

• Both phosphorus and oxygen atoms

• Oxygen atoms

• Neither phosphorus nor oxygen atoms

• Phosphorus atoms

Tags

NGSS.MS-PS1-5

How many molecules of cesium fluoride are needed to balance the equation with gallium and fluorine?

• Two

• Three

• One

• Four

Tags

NGSS.MS-PS1-5