Chemical Reactions

A student performs an experiment, and the results are shown below:

Before: white baking soda and clear vinegar are separated

After: the baking soda and vinegar are mixed together forming gas bubbles

Which statement supports that a chemical change took place?

• A new substance was formed.

• Changes in color occurred.

• The original substances were present after the reaction.

• A physical change in the baking soda occurred.

Tags

7-PS1-2

A chemical reaction is shown below:

Fe₂O₃ + H₂S --> FeO + S + H₂O

What does the arrow (-->) in this chemical reaction represent?

• coefficient

• subscript

• products

• yields

Tags

7-PS1-2

How is a solution created?

• mixing 2 solids together

• evenly dissolving 1 substance in another

• mixing 2 substances together that stay separated

• creating a chemical change between 2 substances

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7-PS1-2

Which of the following is NOT an example of a solution?

• lemonade

• coffee

• water

• kool-aid

Tags

7-PS1-2

When nitrogen gas (N₂) reacts with hydrogen gas (H₂), it forms a new substance called ammonia (NH₃). When iron (Fe) is added to the reaction, the rate of the reaction speeds up. What is the catalyst in this reaction?

• H₂

• NH₃

• Fe

• N₂

Tags

7-PS1-2

What is the number written below the element that represents the number of atoms?

• subscript

• formula

• element

• coefficient

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7-PS1-2

When oxygen and iron combine together in a moist environment (environment with water), rust forms because of a...

• physical reaction

• change in density

• chemical reaction

• change in temperature

Tags

7-PS1-2

Which correctly represents a chemical equation?

• products --> reactants

• reactants --> products

• coefficients --> subscripts

• subscripts --> coefficients

Tags

7-PS1-2

In the chemical equation shown, what are the products of the reaction?

NH₃ + CO₂ --> CH₄N₂O + H₂O

• NH₃ + CO₂

• NH₃ + CH₄N₂O

• CO₂ + H₂O

• CH₄N₂O + H₂O

Tags

7-PS1-2

In the chemical equation shown, what are the reactants?

MgSO₄ + H₂O --> Mg⁺² + SO₄⁻² + H₂O

• Mg⁺² + SO₄⁻² + H₂O

• MgSO₄ + Mg⁺²

• MgSO₄ + H₂O

• H₂O + Mg⁺² + SO₄⁻²

Tags

7-PS1-2