Atoms, Elements & Compounds
Which statement best describes an atom?
A. A group of different compounds
B. The smallest unit of an element
C. A type of chemical reaction
D. A substance that speeds up reactions
B. The smallest unit of an element.
Why do atoms form chemical bonds?
A. To join with other atoms
B. To stop all chemical reactions
C. To become enzymes
D. To destroy elements
A. To join with other atoms
Which substance makes up a large portion of living organisms?
A. Water
B. Iron
C. Oxygen gas
D. Salt
A. Water
During a chemical reaction, the substances present at the beginning are called:
A. Enzymes
B. Products
C. Reactants
D. Elements
C. Reactants
What is the main job of an enzyme?
A. Turn water into an element
B. Create new atoms
C. Speed up chemical reactions
D. Stop all reactions
C. Speed up chemical reactions
What would you have if several atoms of the same type were together?
A. An element
B. An enzyme
C. A chemical reaction
D. A property of water
A. An element
What happens when atoms form a chemical bond?
A. They stop containing electrons
B. They become connected
C. They disappear
D. They become cells
B. They become connected
Water is described as polar. Why is this important?
A. It makes water an element
B. It prevents water from changing temperature
C. It helps water dissolve many substances
D. It prevents chemical reactions
C. It helps water dissolve many substances
The substances formed at the end of a chemical reaction are called:
A. Reactants
B. Products
C. Atoms
D. Bonds
B. Products
What would most likely happen to many reactions in your body without enzymes?
A. They would happen instantly
B. They would happen too slowly
C. They would create new elements
D. They would no longer need reactants
B. They would happen too slowly
Water is made of hydrogen and oxygen chemically bonded together. Water is therefore a:
A. Atom
B. Element
C. Compound
D. Enzyme
C. Compound
What would happen if atoms could no longer form chemical bonds?
A. Enzymes would become atoms
B. Water would become an element
C. Chemical reactions would happen faster
D. Living things would have difficulty forming molecules and compounds
D. Living things would have difficulty forming molecules and compounds
What would happen if water could no longer dissolve many substances?
A. Cells would immediately make more atoms
B. Cells could have difficulty transporting nutrients and wastes
C. Enzymes would turn into elements
D. All chemical reactions would speed up
B. Cells could have difficulty transporting nutrients and wastes
What happens to atoms during a chemical reaction?
A. They are rearranged into new combinations
B. They are completely destroyed
C. New atoms suddenly appear
D. They stop being matter
A. They are rearranged into new combinations
An enzyme usually works with a specific substance called its:
A. Substrate
B. Product
C. Element
D. Atom
A. Substrate
What would happen if hydrogen and oxygen atoms chemically bonded to form water?
A. The atoms would disappear
B. A compound would form
C. An element would form
D. The atoms would become enzymes
B. A compound would form
Two atoms share electrons with one another. What type of bond has most likely formed?
A. Covalent bond
B. Enzyme bond
C. Reaction bond
D. Water bond
A. Covalent bond
Why does water help organisms maintain a stable temperature?
A. Water prevents all energy from entering cells
B. Water cannot change temperature
C. Water creates new atoms when heated
D. Water can absorb a large amount of heat before changing temperature greatly
D. Water can absorb a large amount of heat before changing temperature greatly
What would most likely show that a chemical reaction has occurred?
A. A solid has been cut into smaller pieces
B. An object has moved across a table
C. Water has been poured into another cup
D. New substances have formed
D. New substances have formed
What would most likely happen if an enzyme changed shape so its substrate could no longer fit?
A. The enzyme would become water
B. The reaction would always happen faster
C. The substrate would become an atom
D. The reaction would slow down or stop
D. The reaction would slow down or stop
A substance contains carbon, hydrogen, and oxygen atoms chemically bonded together. Which statement is most accurate?
A. It must be an element
B. It is a compound because different elements are chemically bonded
C. It is an atom because it contains atoms
D. It cannot be part of a living organism
B. It is a compound because different elements are chemically bonded
Why are chemical bonds important to living organisms?
A. They make all substances identical
B. They prevent atoms from interacting
C. They allow atoms to combine into molecules needed by cells
D. They stop chemical reactions from occurring
C. They allow atoms to combine into molecules needed by cells
A person begins sweating during exercise. How does water in sweat help cool the body?
A. Evaporation removes heat from the body
B. Water creates cold atoms
C. Sweat stops all chemical reactions
D. Water changes into an enzyme
A. Evaporation removes heat from the body
During a chemical reaction, bonds in the reactants are broken and new bonds form. What is produced?
A. New substances
B. New types of atoms
C. New elements from nothing
D. More matter than existed before
A. New substances
A person's body temperature becomes dangerously high and some enzymes begin to change shape. What could happen?
A. Some chemical reactions could slow down because the enzymes no longer work correctly
B. The body would begin creating new elements
C. All atoms would lose their chemical bonds immediately
D. Every reaction in the body would become faster
A. Some chemical reactions could slow down because the enzymes no longer work correctly