Chemistry CFE

Which of the following is LEAST likely to dissolve in water?

• nonpolar fats and oils

• polar sugar molecules

• salt made of a positive sodium ion and a negative chloride ion

• all of the substances will dissolve easily in water

Small insects can walk across the surface of calm water. Their feet push the surface of the water down slightly, somewhat like a person walking across a trampoline, but they do not break the surface. What is the best explanation for why this happens?

• The insects are light enough so that they do not break the hydrogen bonds holding the water molecules together

• The insects actually use their wings to hover slightly above the water's surface and they only skim it with their feet

• The insects' feet are non-polar, so they are repelled by the polar water molecules and are pushed away from the water's surface

• The insects are small enough to see the individual water molecules, so they are able to step carefully from one molecule to the next

Tags

NGSS.MS-PS2-5

A(n) _______ is a substance with a pH greater than 7.

• Base

• Acid

• Buffer

• Water

What is the only substance with a neutral pH of 7?

• Milk

• Orange Juice

• Water

• Blood

What makes something radioactive?

• elements with an atomic number above 81

• an unstable nucleus

• contaminated sewage

• It decays over time

Tags

NGSS.HS-PS1-8

Has the symbol

• Alpha

• Beta 

• Gamma

What is a coefficient?

• The small number on the right of the chemical symbol.

• The large number in front of a chemical formula.

• The number in between the chemical symbols.

• The number behind a chemical formula.

What is the part of the chemical equation in green called? 
Fe + S --> FeS

• products

• reactants

• yield

• chemical formula

What coefficient should be used to make the following equation balanced?
N₂+O₂--> _NO 

• 1

• 2

• 3

• 4

Tags

NGSS.MS-PS1-5

H₂O

• element

• compound

Tags

NGSS.MS-PS1-1