Unit 1 Test 2021

Which phrase best describes an atom?

• substance made of different elements

• smallest basic unit of matter

• substance that includes covalent bonds

• contains electrons in its nucleus

How are atoms held together in molecules?

• They form covalent bonds

• They form ions

• They break hydrogen bonds

• They combine to form polymers

Which property of water is the result of hydrogen bonds?

• polarity of water molecules

• high specific heat

• low boiling point

• no cohesion among water molecules

Which property of carbon makes it the "building block of life"?

• its covalent bonding

• its ability to dissolve substances

• its specific heat

• its hydrogen bonding

What are the four main groups of carbon-based molecules?

• starches, cholesterol, fatty acids, and amino acids

• sugars, cellulose, triglycerides, and monosaccharides

• polysacharides, sugars, oils, and polymers

• carbohydrates, lipids, proteins, and nucleic acids

What is the term for the substances that are changed during a chemical reaction?

• products

• catalysts

• enzymes

• reactants

The function of a catalyst in a chemical reaction is to increase the

• reaction rate

• activation energy

• pH

• number of substances

An atom becomes an ion when its number of protons charges

• True

• False

Some ions are positively charged, and some ions have no charge

• True

• False

The formation of an ion results in a full outermost energy level

• True

• False