Law of Conservation of Mass and Balancing Equations

What is the Law of Conservation of Mass?

• Mass is created in a chemical reaction

• Mass is created in a physical change

• New chemicals formed from a chemical reaction have a larger overall mass than the original reactants

• Mass is never created or destroyed

Tags

NGSS.MS-PS1-5

In reaction A +B --> C, reactants A + B have a total mass of 9g. What is the mass of product C?

• 4g

• 5g

• 9g

• 14g

Tags

NGSS.MS-PS1-5

In reaction A +B --> C, reactant A has a mass of 4g and product C has a mass of 9g. What is the mass of reactant B

• 4g

• 5g

• 9g

• 14g

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

7 g of hydrogen reacts with 17 g of oxygen to produce ______ g of water

• 14

• 24

• 38

• 62

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

During a chemical reaction matter cannot be created or destroyed.

• True

• False

Tags

NGSS.MS-PS1-5

• 2

• 3

• 4

• 8

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-1

Is this equation balanced?

• Yes

• No

Tags

NGSS.MS-PS1-5

In the equation shown, what are the product(s)?

• N₂ + H₂

• NH₃

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

Is this equation balanced?

• Yes

• No

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

To balance an equation you should:

• ONLY change subscripts.

• ONLY change coefficients.

• Change BOTH subscripts and coefficients.