Grade 7 Chemistry

When vinegar and baking soda are combined, bubbles begin to form. Explain how the formation of bubbles is evidence of a chemical reaction.

• Bubbles are cool.

• Bubbles are evidence of a chemical reaction because they indicate that a solid was formed.

• Bubbles are REALLY cool

• Bubbles are evidence of a chemical reaction because they indicate that gas was formed.

Tags

NGSS.MS-PS1-2

Scenario: When Juan got home from school, he noticed a foul smell coming from the kitchen. He decided to investigate the smell and found fruit sitting on the counter. There was evidence that a chemical reaction had occurred. When he looked at the fruit, he saw that it had turned brown and was soft to the touch.

Question: What is EVIDENCE that supports the claim that a chemical reaction took place?

• It looked gross.

• It changed color, smelled bad, and turned soft.

• It did not taste good.

• It smelled bad and turned soft.

Tags

NGSS.MS-PS1-2

Which of the following is the best description of the results of a chemical reaction?

• A new substance with different properties is formed

• The substance seems to disappear after dissolving in water

• The substance changes from liquid to solid at a low temperature

• The reaction can be reversed to get back the original substance

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Hint: gas bubbles are being produced. Chemical reaction or not?

• yes

• no

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Identify the reactant(s) and product(s) of the reaction.

• All three are reactants and none are products.
• Hydrogen and water are the reactants, and oxygen is the product.
• Water and oxygen are the reactants, and hydrogen is the product.
• Hydrogen and oxygen are the reactants, and water is the product.
  

What indicates a chemical reaction occurred?

• Heat or Light is released
  heat or light is produced
• gas (bubbles) produced
• color change
• all of the above

Tags

NGSS.MS-PS1-2

1. How is a chemical change different from a physical change?

• there is no difference

• a physical change creates a new substance

• a chemical change creates a new substance

Tags

NGSS.MS-PS1-2

A student observes some sugar as it is heated and burns. The student concludes that a chemical reaction has occurred. Which of the following observations about the burning sugar provides evidence of a chemical reaction?

• Heat is added to the sugar crystals.

• The sugar melts and becomes a liquid.

• Gas is produced as the sugar turns black.

• No evidence of chemical reaction is present.

Tags

NGSS.MS-PS1-2

Chemical properties of a substance include all of the following except..

• its boiling point 
• its toxicity 
• its flammability 
• its reactivity 

Tags

NGSS.HS-PS1-1

A Precipitate forms 

• when a gas is bubble through a liquid 
• a lighter taper causes a gas to burn 
• in a liquid or gas  after a reaction and causes cloudiness (caused by a solid forming) 

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5