Grade 7 Acids and Bases

What does this label mean?

• Wash your hands using the following substance.

• Contains corrosive substances, which can cause burns.

If an acid is combined with a base of equal strength, the result will most likely be

• impossible to tell without testing the pH.

• a stronger acid.

• a neutral solution.

• a stronger base.

Select the correct pair of words that fits into this sentence.

________are corrosive substances characterized as having a strong smell, a sour taste, and a ________.

• Bases; pH less than 7

• Acids; pH greater than 7

• Bases; pH greater than 7

• Acids; pH less than 7

Which of the following is a base?

• Orange juice

• water

• lemon juice

• dishwashing detergent

Haleema 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.

Litmus paper can be used to determine the _______ of a substance.

• relative volume

• temperature

• chemical formula

• relative pH

Litmus changes to the colour _____ in the presence of an acid.

• red

• yellow

• blue

• green

Yolene's teacher hands out test tubes filled with different chemicals and tells the students to identify their liquid as an acid, base, or neutral chemical. Yolene's test tube contains a clear chemical. She adds phenolpthalein to her test tube and gently moves the test tube from side to side. A few moments later, the chemical in the test tube turns bright pink.

• Yolene has an acidic chemical.

• The type of chemical that Yolene has in her test tube cannot be determined.

• Yolene has a neutral chemical.

• Yolene has a basic chemical.

Which of the following is an acid?

• vinegar

• shampoo

• water

• baking soda

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

• slightly acidic.

• strongly acidic.

• slightly basic.

• strongly basic.