Balancing Chemical Equations & States of Matter

A teacher asks her students to examine titles of four scientific articles. Which titled article is specifically about a chemical change?

• How Baking Soda Reacts with Vinegar

• How Rust Can Be Scraped off of Metal

• How Metals Respond to Electrical Currents

• How Elements Can Change Phase When Heated

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

Identify ALL of the chemical changes

• Boiling water

• Burning a marshmallow

• Fireworks going off

• Cutting your hair

• Dying your hair

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NGSS.MS-PS1-2

If you cut a wooden block in half, each half would have:

• Half the density of the original piece

• Twice the density of the original piece

• The same density as the original piece

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NGSS.MS-PS1-2

Which best represents a balanced equation?

• 120 grams of carbon plus 20 grams of oxygen → 200 grams of carbon dioxide

• 120 grams of carbon plus 50 grams of oxygen → 200 grams of carbon dioxide

• 120 grams of carbon plus 80 grams of oxygen → 200 grams of carbon dioxide

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NGSS.MS-PS1-5

NGSS.MS-PS1-2

The following chemical reaction occurs.

2H2O2 → 2H2O + O2

How many atoms of hydrogen are involved in the reaction?

• 1

• 2

• 4

• 8

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NGSS.MS-PS1-5

NGSS.MS-PS1-1

Which is best represented by the equation?

2Mg + O₂ 2MgO

• Law of Conservation of Energy

• Law of Conservation of Mass

• Law of Superposition

Tags

NGSS.MS-PS1-5

When chemicals react in a closed container, which must be true?

• The mass both before and after the reaction is the same.

• The mass both before and after the reaction is variable.

• The same number of compounds is present both before and after the reaction.

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

A chemistry teacher combines 20 grams of lemon juice with 25 grams of baking soda in a flask covered with a balloon. The flask and balloon have a combined mass of 105 grams. What is the mass of the entire setup after a reaction has occurred?

• 45 g

• 150 g

• 605 g

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

If 100 grams of vinegar and 5 grams of baking soda are poured in a container, a small amount of gas will be produced. What will the final mass of the products be if the gas is trapped in the container?

• 100 g

• 104 g

• 105 g

• 110 g

Tags

NGSS.MS-PS1-5

NGSS.MS-PS1-2

An ice cube is put into a heated pan. What will most likely happen to the molecules in the ice as the ice is heated?

• The molecules will begin to move slower.

• The molecules will begin to move faster.

• The molecules will begin to increase in density.

• The molecules will begin to condense in air.

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4