PSSA Review 8th grade Science

Which of these is an example of a compound?

• Two fluorine atoms bonded together

• A piece of solid gold made of millions of gold atoms

• An atom of nitrogen bonded to three atoms of hydrogen

• A drop of liquid mercury made of millions of mercury atoms

Tags

NGSS.MS-PS1-1

A scientist combines three elements and observes the results. She concluded that the elements formed a compound when they combined. Which of these observations best supports the scientist's conclusion?

• Each element had some unique properties

• All of the elements shared some properties

• The combination of the three elements shared some properties with the elements

• The combination of the three elements had some properties that none of the elements had.

What are the reactants in the chemical reaction that forms rust.

• Water, iron and oxygen

• rust

• Rust and Carbon Dioxide

• Water and Oxygen

Tags

NGSS.MS-PS1-5

Which of the following is a compound?

• Solid Gold (Au)

• Nitrogen gas (N2)

• Liquid Water (H2O)

• Hydrogen Gas (H2)

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NGSS.MS-PS1-1

Which of the following is an example of chemical change?

• A chunk of metal being hammered flat

• a piece of chalk being crushed into powder

• a solid rock melting into magma

• an iron bridge turning brownish over the years

Tags

NGSS.MS-PS1-2

A scientist is studying a chemical reaction in which potassium sulfide (K₂S) decomposes into potassium and sulfide.

• K₂S ----> K + S

• K + S ---->K₂S

• K₂S + S ----> K

• K + K₂S ----> S

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following never changes during a chemical change?

• arrangement of atoms

• number of molecules

• total number of atoms

• color of the reactants

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

which of the two combinations most likely produced a mixture?

• 1 and 2

• 1 and 3

• 2 and 3

• 3 and 4

Tags

NGSS.MS-PS1-2

What did combination 4 produce?

• An element that was pure

• A mixture which was chemically combined

• A compound which was chemically combined

• A mixture that was physically combined

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Why did the black metal in combination 3 sink to the bottom of the liquid?

• It was heavier

• it was more massive

• it had a density greater that the liquid it was placed in

• it had a density less that the liquid it was placed in

Tags

NGSS.MS-PS1-2