Acids and Bases

Which of the following word pairs correctly completes the sentence below?
_______ are corrosive substances characterized as having a strong smell, a sour taste, and a _______.

• Acids; pH less than 7
• Acids; pH greater than 7
• Bases; pH greater than 7
• Bases; pH less than 7

Tags

NGSS.MS-PS1-1

Holly has an unknown substance in a beaker. She wants to determine the relative pH of the unknown substance. She places a piece of blue litmus paper into the substance, and the litmus paper stays blue.
The substance in the beaker

• is a base.
• has a neutral pH.
  
• is an acid.
• does not have a pH.

Which of the following is a base?

• orange juice
• water
• vinegar
• dishwashing detergent

Which of the following statements is correct?

• Blue litmus paper turns red when placed in a base.
• Red litmus paper turns blue when placed in a base.
• Blue litmus paper stays blue when placed in an acid.
• Red litmus paper stays red when placed in a base.

Tags

NGSS.MS-PS1-2

The pH of a solution is tested, and it is found to be a basic solution. Of the following choices, what could the pH have been?

• 3
• 9
• 7
• 5

Human blood has a pH between 7.35 and 7.45. Which of the following best describes human blood?

• strongly acidic
• slightly acidic
• strongly basic
• slightly basic

Tags

NGSS.MS-PS1-2

When using pH paper, the pH of a solution can be determined by looking at the _______ of the paper.

• texture
• color
• length
• mass

Many cleaning solutions are bases. Which of the following is a property of most bases?

• feels slippery
• white color
• can only be liquid
• tastes sour

Pure water has a pH of 7. Pure water _______.

• is a base
• is a neutral substance
• could be either an acid or a base
• is an acid

What methods can you use to measure the pH of a solution?

• Observing color or clarity
• Measuring mass or volume
• Measuring density or electrical conductivity
• Using acid base-indicators or pH meters