Homework 2.1

What does all matter have in common?

• It is liquid at room temperature

• It is made up of atoms

• It is visible

• It is electrically neutral

Which statement best describes compounds?

• Compounds are collections of several atoms of the same element

• Compounds are made up of atoms of one or more elements bonded together

• Compounds rarely occur in nature and are often synthesized by humans

• Compounds are composed of atoms that are not likely to react with one another

Which of the following are examples of matter? Select all that apply

• sunlight

• heat

• water

• grass

• air

An animal's stomach contains enzymes that break down food into smaller molecules that the animal's cells can use. Enzymes perform this function by:

• participating in chemical reactions

• increasing the reaction temperature

• decreasing the activation energy

• lowering the pH

A chemical reaction proceeds until it reaches an equilibrium. Which statement is true when the reaction is at equilibrium?

• All the reactants are used up.

• The reaction is completed and will not change.

• One reactant is used up, but one or more of the other reactants are still present.

• Both products and reactants are present.

How do the properties of elements compare to the properties of the compounds they form?

• The properties of the elements may differ from the properties of the compounds they form.

• The properties of the compounds are always the same as the elements that are in the compound.

• The properties of the compound will change only if the elements in the compound are exposed to heat.

• The properties of the compound are the same as the properties of the individual atoms in the compound.

Which of the following is not a property of water

• high specific heat

• cohesion

• relatively low boiling point

• adhesion

How do temperature and pH affect an enzyme that a chemical reaction depends on?

• They can break down the reactants.

• They can break down the products.

• They can change the shape of the enzyme.

• They can cause the chemical reaction to reverse.