MS PS1 2

The chemical reaction that produces soap is called saponification. During one type of saponification, oil and sodium hydroxide undergo a chemical change to produce glycerol and soap. As a result of this reaction, the soap has different properties than the oil and sodium hydroxide. Some of these properties are what give soap its cleaning ability.

Which of the following statements are true? Select all that apply.

• Together, the products of a chemical reaction have the same arrangement of atoms as the reactants

• A substance's chemical structure affects its properties

• Soap is a reactant in the saponification reaction

• A chemical change occurs during saponification

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Sam is making soap at home using the saponification reaction. Her soap recipe uses coconut oil.

The melting point of coconut oil is 76°F.

Sam is making the soap in her kitchen, where the temperature is currently 82°F.

Which of the following statements are true?

Select all that apply.

• A substance's melting point is higher when the attractions between its molecules are stronger

• Because the temperature in Sam's kitchen is higher than the melting point of the coconut oil, the coconut oil is a liquid

• A large amount of coconut oil has a higher melting point than a small amount of coconut oil

Tags

NGSS.MS-PS1-4

Another characteristic property of a substance is its solubility in water. A substance's water solubility describes how well the substance will dissolve in water at a given temperature. Like other characteristic properties, water solubility is determined by a substance's chemical structure.

Some substances, such as sugar and table salt, have chemical structures that make them highly soluble in water. Other substances, such as dirt and oil, have chemical structures that make them insoluble, or poorly soluble, in water.

Coconut oil is _____ in water. So coconut oil dissolves _____ in water.

• soluble; dissolves well

• soluble; does not dissolve well

• insoluble; dissolves well

• insoluble; does not dissolve well

Tags

NGSS.MS-PS1-2

After leaving her soap to harden overnight, Sam cuts the block of soap into rectangular bars.

The temperature in Sam's kitchen is 82°F, the same as when she began making the soap.

At 82 F the coconut oil soap is a _____. So the melting point of coconut oil soap is ______ than the melting point of coconut oil. This means that the attraction between molecules of coconut oil soap must be _______ than attractions between molecules of coconut oil.

• solid....lower...weaker

• liquid...lower...stronger

• solid.... higher....stronger

• liquid..higher...weaker

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-4

A bar of Sam's coconut oil soap has a mass of 132 grams. The rectangular bar is 8 centimeters long, 6 centimeters wide, and 2.5 centimeters high.

Hint: Volume is lxwxH Density: M/V

Calculate the density of Sam's coconut oil soap.

• 15,840 g/cm³

• 1.1 g/cm³

Tags

NGSS.MS-PS1-2

The density of coconut oil is 0.9 grams per milliliter, and the density of coconut oil soap is 1.1 grams per cubic centimeter. Even though the densities of coconut oil soap and coconut oil have different units, they can be compared directly. This is because a cubic centimeter and a milliliter have the same volume. So, a solid with a density of 1 gram per cubic centimeter and a liquid with a density of 1 gram per milliliter are equally dense.

Which substance is more dense?

• coconut oil

• coconut oil soap

Sam washes her hands with coconut oil soap and running water. As the water dissolves the soap, a lather forms and the soap bar gets smaller.

Coconut oil soap ____ in water. So coconut oil soap is ____ in water

• dissolves well...soluble

• does not dissolve well...soluble

• dissolves well...insoluble

• does not dissolve well...insoluble

Tags

NGSS.MS-PS1-2

Why do coconut oil and coconut oil soap have different characteristic properties? Select all that apply.

• The attractions between coconut oil soap molecules are stronger than the attractions between coconut oil molecules

• Coconut Oil underwent a chemical change to become coconut oil soap

• Coconut Oil and Coconut Oil Soap have different chemical structures

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

NGSS.MS-PS1-5