Chemistry Pre-Ap

Five cubes of iron are tested in a laboratory. The tests and the results are shown in the table.  Which tests demonstrate chemical properties?

• 1, 3, and 4
• 1, 3, and 5
• 2 and 4
• 2 and 5

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

How many of the properties listed for the element sodium are considered physical properties?

• 1
• 2
• 3
• 4

2H₂(g) + O₂(g) → 2H₂O(ℓ)
How would you classify the change above?  Explain.

• Physical Change:
  Bonds are broken and new bonds are formed.
  Identity CHANGES
• Chemical Change:
  NO bonds are broken and NO new bonds are formed.
  Identity Stays the SAME
• Physical Change:
  NO bonds are broken and NO new bonds are formed.
  Identity Stays the SAME
• Chemical Change:
  Bonds are broken and new bonds are formed.
  Identity CHANGES

A student prepares two separate samples by combining a salt (NH₄Cl), sand (SiO₂), and water (H₂O). Both samples are at the same temperature, thoroughly stirred, and then allowed to stand. The mass of each component used to make the samples is listed in the data table shown.  How would you best classify the prepared samples?

• Element
• Compound
• Heterogeneous Mixture
• Homogeneous Mixture

Tags

NGSS.MS-PS1-1

A student prepares two separate samples by combining a salt (NH₄Cl), sand (SiO₂), and water (H₂O) at 15°C. Both samples are thoroughly stirred and allowed to stand. The mass of each component used to make the samples is listed in the data table shown.  How would the student separate out the sand by physical means from the rest of the sample?

• Add additional water to dissolve the sand.
• Evaporate the water.
• Pour the sample through a filter paper.
• The components can not be separated by physical means.

Tags

NGSS.MS-PS1-2

The sample pictured changes from the solid state to the gas state when heated.   Does this change represent a chemical or physical change?

• Physical Change: 
  The identity of the substance changes.
• Physical Change:
  The identity of the substance stays the same.
• Chemical Change:
  The identity of the substance changes.
• Chemical Change:
  The identity of the substance stays the same.

Tags

NGSS.MS-PS1-4

Which of the following changes represents a physical change?

• BOTH
  Change 1
  AND
  Change 2
• NEITHER 
  Change 1 
  NOR
  Change 2
• ONLY
  Change 1
• ONLY 
  Change 2

At 1 atm of pressure, equal masses of H₂O(s), H₂O(ℓ), and H₂O(g) have

• the same density
• the same distance between molecules
• different volumes
• different percent compositions of elements

Tags

NGSS.HS-PS1-3

Examine the samples in the image shown.  The identity of the material in each box is the same.   Which sample would be most easily compressed?

• Solid
• Liquid
• Gas
• All samples are equally compressible because their identities are the same.