Characteristics of Chemical Reactions Assessment

Hydrogen and oxygen react to create water. At an atomic level, how do we know that a chemical reaction has occurred?

• Hydrogen molecules are negative, and oxygen positive.

• 
  The hydrogen and oxygen atoms regroup into a new molecule.

• Oxygen atoms are much larger than hydrogen atoms.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

The chart below shows the results of combining various substances.

Which of the following statements is true?

• 
  We know combining Substances A and B resulted in a chemical reaction because a gas was formed.

• We know combining Substances C and D resulted in a chemical reaction because there wasn't a temperature change.

• We know combining Substances A and B resulted in a chemical reaction because there wasn't a temperature change.

• 
  None of the combinations resulted in a chemical reaction because neither one had a color change.

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

Rust forming on a piece of iron is an example of which of the following:

• • A physical change because the process can be reversed

• A chemical change because oxygen atoms from the atmosphere bonded with the iron atoms

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following statements is true?

• • Cutting paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

• 
  Freezing water is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

• Burning paper is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

• 
  Melting ice is an example of a chemical reaction because a new substance is formed and the process cannot be undone.

Tags

NGSS.MS-PS1-2

A student conducted an experiment where they mixed a solution of blue sodium bicarbonate and purple magnesium sulfate in a baggy. The following observations were noted:

1. Small hard particles could be felt in the bag.

2. 2. The bag felt colder

3. 3. The solution was blue

Explain which 2 observations are evidence that a chemical reaction is taking place.

Tags

NGSS.MS-PS1-2

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

Tags

NGSS.MS-PS1-2

Four students performed four different investigations by combining different substances. Their results are shown in the table below.

In which experiment did a chemical reaction take place?

• Experiment 1

• Experiment 2

• Experiment 3

• Experiment 4

Tags

NGSS.MS-PS1-2