General Chemistry Review

What can scientists add to the water that flows through old lead pipes to make it safe, and how does it work?

• Orthophosphate - it creates a barrier (passivation layer) that stops heavy metals like lead from leaching into the water

• Sodium Chloride (salt) - it kills bacteria and destroys metals like lead in the water

• Dawn Dish Soap - destroys oil in the water & cleans the water

• Filters on the street water lines- they stop heavy metals from reaching the homes

Tags

NGSS.HS-ESS3-4

NGSS.HS-ETS1-3

NGSS.HS-PS1-2

What is a safe level of lead in drinking water, according to the EPA?

• 5ppm

• 150ppm

• 15ppm

• 100ppm

What unique crust should be in old pipes to protect people from the lead/iron?

• Passivation Layer

• Precipitation Layer

• Polymerase Layer

• Orthophosphate pH Layer

Tags

NGSS.HS-ETS1-3

After switching back to the original water source, what problem still existed with the pipes due to a lack of proper water chemistry for more than a year?

• The passivation layer was already gone, so lead was still leaching into the water

• The water wasn't being treated even though they switched back to their original supplier

• The new pipes had been installed in homes but people weren't using them

• No one used the water at all so it just continued to sit in the old pipes, allowing bacteria to grow.

Tags

NGSS.HS-ESS2-5

NGSS.HS-ESS3-1

• Synthesis

• Decomposition

• Single displacement

• Combustion

In an exothermic reaction, the energy of the reactants is:

• Higher than the energy of the products

• Lower than the energy of the products

• Equal to the energy of the products

• Unrelated to the energy of the products

Tags

NGSS.HS-PS1-4

Which of the following is an example of a single replacement reaction?

Tags

NGSS.MS-PS1-2

Which of the following is an example of a double replacement reaction?

• Synthesis

• Decomposition

• Single displacement

• Double displacement

Which of the following is a balanced chemical equation for the reaction between hydrogen gas and oxygen gas to form water?

Tags

NGSS.HS-PS1-7