Physical and Chemical Changes; Law of Conservation of Mass

Mixing baking soda and vinegar causes bubbles of carbon dioxide gas to form. Which of the following statements is true?

• A chemical change happened because a color change occurred

• A chemical change happened because a precipitate formed

• A physical change happened because the vinegar boiled into a gas

• A chemical change happened because a new gas was released

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NGSS.MS-PS1-2

Which BEST explains why the total mass of the product(s) would be LESS than the total mass of the reactant(s) after a chemical reaction?

• Gases were released into the air during the reaction

• Precipitates were created during the reaction

• Atoms involved in the reaction lost mass

• A physical change has occurred

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

A student mixed some food coloring into some water. Which of the following statements is true?

• A chemical change happened because a new substance formed

• A chemical change happened because a precipitate formed

• No chemical change happened because no new substance formed.

• No chemical change happened because the water changed phase

Tags

NGSS.MS-PS1-2

Plants create food by the process of photosynthesis. In this reaction, the plant starts with 6 atoms of carbon. In order for the matter to be conserved and the chemical reaction to stay balanced, how many atoms of carbon should be present AFTER this reaction?

• 2 atoms of carbon

• 3 atoms of carbon

• 6 atoms of carbon

• 12 atoms of carbon

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following describes a chemical property?

• Conductivity

• Malleability

• Density

• Reactivity with air

Tags

NGSS.MS-PS1-2

In any chemical reaction, the total amount of matter before the reaction and the total amount of matter after the reaction must STAY THE SAME according to:

• The Law of Equality

• The Law of Conservation of Energy

• The Law of Balance

• The Law of Conservation of Mass

Tags

NGSS.MS-PS1-5

17. What is a precipitate?

• A solid that can be formed by combining two liquids

• A change in temperature

• A measuring tool

• An element

Tags

NGSS.MS-PS1-2

Which of the following shows ONE example of a physical change and ONE example of a chemical change?

• Dissolving powder and shredding paper

• Freezing water and burning coal

• Rusting iron and baking a cake

• Boiling water and melting wax

Tags

NGSS.MS-PS1-2

CO₂ + H₂O ----> C₆H₁₂O₆ + O₂

What is wrong with the reaction above?

• It does not create anything new

• It is not balanced properly

• It has no products

• It has no reactants

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

How does a balanced chemical equation satisfy the Law of Conservation of Mass?

• During a chemical reaction, matter is destroyed

• During a chemical reaction, one or more new substances are formed

• During a chemical reaction, the total number of atoms increases

• During a chemical reaction, the total amount of matter stays the same

Tags

NGSS.MS-PS1-5