CLASS 7 SCIENCE

He

Based on this symbol, what can you tell about Helium (He)?

• Helium is a compound

• Helium is an element

• helium is a metal

• helium is a mixture

Tags

NGSS.MS-PS1-1

H₂O

How many types of elements are in this compound?

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-1

Which combination of letters can be used as a chemical symbol for an element?

• NP

• Pks

• Cl

• FeOB

Water ( H₂O) is a compound because-

• it is made of two different elements

• useful to humans

• a gas at room temperature

• given off by plants

Tags

NGSS.MS-PS1-1

Which contains only CHEMICAL changes (new substance formed or cannot be undone)?

• Silver spoon tarnish

  Leaves change color

  Water separating into hydrogen and oxygen

• Ice melting

  Sugar Cube dissolving

  Paper tearing

• Dry ice goes from solid to liquid

  Your breath condensing on a window

  Glass breaking

• Mixing flour, salt, and sugar

  Sanding wood

  Grinding something into powder

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which list contains only elements and a reason why they are elements?

• H₂O, NaCl, N₂, CO₂, Substances are elements because they they contain more than one chemical symbol.

• Kr, Ne, Ar, He, Substances are elements because they are noble gases.

• Cl_2, H_2, Na, He, Substances are elements because they are pure.

• F₂, O_2, Li, H, Substances are elements because they all have chemical symbols.

Carbon (C) is considered an element while Carbon Dioxide (CO₂) is considered a compound. That is because Carbon Dioxide is -

• a gas

• made of two elements

• given off by plants

• useful to us

Tags

NGSS.MS-PS1-1

Rust & Tarnishing is ALWAYS and example of a chemical change/reaction?

• True

• False

Tags

NGSS.MS-PS1-2

A molecule is

• two or more atoms bonded together
• one type of atom
• smaller than an atom 
• an element

Tags

NGSS.MS-PS1-1

How many atoms are there TOTAL in:
H₂SO₄

• 6
• 5
• 7
• 3

Tags

NGSS.MS-PS1-1