Law of Conservation of Mass

A chemical reaction is balanced when

• both sides have the same elements

• Both sides have the same  number of atoms

• Same subscripts

• Same coefficients

Tags

NGSS.MS-PS1-5

Which of these is not a chemical reaction?

• Burning of wood
• Milk going bad
• Mixing vinegar and baking soda
• Melting of ice

Tags

NGSS.MS-PS1-2

A precipitate is a 

• liquid that forms when two solids are reacted
• a solid that forms when two liquids are mixed
• a gas that forms when vinegar and baking soda react
• a change of color in a solution

Tags

NGSS.MS-PS1-2

If reaction starts with 20g of reactants it should produce 

• a total of 40g of products
• a total of 10g of products
• a total of 80 g of products
• a total of 20g of products

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

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

NGSS.MS-PS1-2

When sodium and chlorine combine to form sodium chloride, sodium chloride is the:

• Originator

• Reactant

• Product

• Produce

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-1

Maria fills a bowl with 200 g of water. She puts the bowl of water in the freezer, and the water freezes. Which will most likely be the mass of the frozen water?

• 50 g
• 100 g
• 200 g
• 400 g

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Does the equation H₂+O₂ →H₂O follow the Law of Conservation of Mass?

• Yes, because the atoms are equal.

• No, because more info is needed.

• No, because there are more atoms in the product.

• No, because there are more atoms in the reactant.

Tags

NGSS.MS-PS1-5

According to the Law of Conservation of Mass, what happens to the wood and oxygen when it is burned?

• The wood disappears.

• It stays the same chemically.

• The atoms in the wood and oxygen rearrange and form smoke and ash.

• Nothing.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

How many grams of OXYGEN would be needed to show conservation of mass in the example below?

• 100 g

• 93 g

• 7 g

• 0 g

Tags

NGSS.MS-PS1-5