Chemistry Chapter on Atoms and Bonds

Questions and Answers

What is an atom?

The smallest unit of matter that cannot be broken down by chemical means.

What are subatomic particles?

Protons, neutrons, and electrons.

What is an element?

A pure substance made of only one kind of atom.

What is a compound?

Substances made up of two or more atoms of different elements. Signup and view all the answers

What are isotopes?

Atoms of an element that contain a different number of neutrons. Signup and view all the answers

What is a chemical bond?

A force that joins atoms. Signup and view all the answers

What do chemical formulas identify?

The elements in a compound and the proportion of those elements. Signup and view all the answers

What is a molecule?

A group of atoms held together by covalent bonds. Signup and view all the answers

What is a covalent bond?

When two or more atoms share electrons to form a molecule. Signup and view all the answers

What is a hydrogen bond?

A weak chemical attraction between polar molecules. Signup and view all the answers

What is a polar molecule?

A molecule with unequal distribution of electrical charges. Signup and view all the answers

What is an ion?

An atom or molecule that has gained or lost one or more electrons. Signup and view all the answers

What is an ionic bond?

Ions of opposite charge interact to form this. Signup and view all the answers

What percent of your body is water?

70% Signup and view all the answers

Water absorbs heat more _____ and retains the energy longer.

slowly Signup and view all the answers

What is cohesion?

An attraction between substances of the same kind. Signup and view all the answers

What is surface tension?

The condition where the attraction of water molecules prevents the surface of water from stretching or breaking. Signup and view all the answers

What is adhesion?

An attraction between different substances. Signup and view all the answers

What is a solution?

A mixture in which one or more substances are evenly distributed in another substance. Signup and view all the answers

_________ of water enables substances to dissolve in water.

Polarity Signup and view all the answers

__________ molecules do not dissolve well in water.

Nonpolar Signup and view all the answers

What are acids?

Compounds that form hydrogen ions when dissolved in water. Signup and view all the answers

What are bases?

Compounds that reduce the concentration of hydrogen ions in a solution. Signup and view all the answers

What does the pH scale represent?

The concentration of hydrogen ions in a solution. Signup and view all the answers

What is the pH of an acid?

0-6 Signup and view all the answers

What is the pH of a neutral compound?

7 Signup and view all the answers

What is the pH of a basic compound?

8-14 Signup and view all the answers

What are carbohydrates?

Organic compounds made of carbon, hydrogen, and oxygen. Signup and view all the answers

_______ is stored in the chemical bonds of carbohydrates.

Energy Signup and view all the answers

What are monosaccharides?

The building blocks of carbohydrates. Signup and view all the answers

What is a disaccharide?

A double sugar formed when two monosaccharides are joined. Signup and view all the answers

What is a polysaccharide?

A macromolecule that consists of chains of three or more monosaccharides. Signup and view all the answers

What is a macromolecule?

A large molecule made up of many smaller molecules. Signup and view all the answers

What is starch?

A polysaccharide made up of many glucose molecules. Signup and view all the answers

What is glycogen?

A polysaccharide made up of many glucose molecules. Signup and view all the answers

What is cellulose?

A polysaccharide that provides structural support for plants. Signup and view all the answers

What are lipids?

Nonpolar molecules that are not soluble in water. Signup and view all the answers

What is saturated fat?

A long chain of carbon atoms with two hydrogen atoms bonded to each carbon atom. Signup and view all the answers

What is unsaturated fat?

A long chain of carbon atoms with one hydrogen atom bonded to each carbon atom. Signup and view all the answers

What are proteins?

Large molecules formed by smaller molecules called amino acids. Signup and view all the answers

What are amino acids?

The building blocks of protein. Signup and view all the answers

What are nucleic acids?

Long chains of smaller molecules called nucleotides. Signup and view all the answers

What are nucleotides?

A small molecule with three parts: sugar, nitrogen base, and phosphate. Signup and view all the answers

What is DNA?

The building block of life which contains two strands of nucleotides. Signup and view all the answers

What are chromosomes?

Store hereditary information and contain long strands of DNA. Signup and view all the answers

What is RNA?

Acts as an enzyme, promoting chemical reactions that link amino acids to form proteins. Signup and view all the answers

What is ATP?

A single nucleotide with two extra energy-storing phosphate groups. Signup and view all the answers

What is energy?

The ability to move or change matter. Signup and view all the answers

What is a chemical reaction?

A process during which chemical bonds between atoms are broken and new bonds are formed. Signup and view all the answers

What are reactants?

The starting material for chemical reactions. Signup and view all the answers

What are products?

The newly formed substances in a chemical reaction. Signup and view all the answers

Energy is _ or ___ when chemical bonds are broken and new ones formed.

absorbed, released Signup and view all the answers

What is metabolism?

All of the chemical reactions that occur within an organism. Signup and view all the answers

What is activation energy?

The energy needed to start a chemical reaction. Signup and view all the answers

What are enzymes?

Substances that increase the speed of chemical reactions. Signup and view all the answers

What are catalysts?

Substances that reduce the activation energy of a chemical reaction. Signup and view all the answers

Most enzyme reactions are ________.

reversible Signup and view all the answers

What is carbonic anhydrase?

An enzyme that increases the reaction rate enabling the body to eliminate carbon dioxide efficiently. Signup and view all the answers

What is a substrate?

A substance on which an enzyme acts during a chemical reaction. Signup and view all the answers

An enzyme acts only on a _____ substrate.

specific Signup and view all the answers

What is an active site?

Deep folds that form pockets in a large protein. Signup and view all the answers

What is table salt?

NaCl Signup and view all the answers

What is a stable atom?

An atom that has a full outer electron level. Signup and view all the answers

The proteins in your body include and _.

collagen, hemoglobin Signup and view all the answers

What is the optimal temperature for enzymes in the body?

37 degrees Celsius Signup and view all the answers

The enzyme that breaks down hydrogen peroxide into water is _________.

catalase Signup and view all the answers

What is amylase?

An enzyme that helps break down starch into glucose. Signup and view all the answers

What is the pH of vinegar?

3-4 Signup and view all the answers

What is the pH of household ammonia?

12 Signup and view all the answers

Study Notes

Atoms and Subatomic Particles

Atoms are the smallest units of matter, consisting of a nucleus (protons and neutrons) and an electron cloud.
Subatomic particles include protons, neutrons, and electrons.

Elements and Compounds

Elements are pure substances made of one type of atom, identified by symbols (e.g., H for hydrogen).
Compounds are formed from two or more atoms of different elements.

Isotopes and Ions

Isotopes vary in neutron number within the same element.
Ions are atoms or molecules with a net charge due to the gain or loss of electrons.

Chemical Bonds

Chemical bonds are the forces that join atoms together.
Covalent bonds involve the sharing of electrons between atoms.
Ionic bonds form through the attraction of oppositely charged ions.
Hydrogen bonds are weak attractions between polar molecules.

Water and Its Properties

Water constitutes about 70% of the human body and has unique properties such as high heat capacity.
Cohesion refers to the attraction between similar substances, while adhesion is the attraction between different substances.
Surface tension is a result of cohesive forces that allow small objects to float on water.

Solutions and Solubility

A solution is a mixture where substances are evenly distributed.
Polar molecules, such as water, dissolve well in water, whereas nonpolar molecules do not (e.g., oils).

Acids, Bases, and pH

Acids release hydrogen ions (H+) in solutions, while bases reduce H+ concentration and increase hydroxide ions (OH-).
The pH scale measures hydrogen ion concentration, ranging from 0 to 14 (acidic: 0-6, neutral: 7, basic: 8-14).

Carbohydrates

Carbohydrates are organic compounds (C, H, O in 1:2:1 ratio) essential for energy, including monosaccharides (simple sugars), disaccharides (double sugars), and polysaccharides (starch, glycogen, cellulose).

Lipids and Fats

Lipids are nonpolar molecules important for cell membrane structure; they include saturated fats (solid at room temperature) and unsaturated fats (liquid at room temperature).

Proteins

Proteins consist of amino acids and serve various functions in organisms.
Enzymes, a type of protein, speed up chemical reactions and are influenced by temperature and pH.

Nucleic Acids

Nucleic acids (DNA and RNA) are long chains of nucleotides that store genetic information and perform various roles in cellular processes.
DNA is double-stranded while RNA is single-stranded and assists in protein synthesis.

Energy in Biological Systems

Energy is stored in chemical bonds (e.g., carbohydrates) and is essential for cellular functions.
ATP is the primary energy currency in cells, derived from glucose metabolism.

Chemical Reactions and Metabolism

Chemical reactions involve breaking and forming bonds to create new substances, categorized into reactants (starting materials) and products (newly formed substances).
Metabolism encompasses all chemical processes within an organism, influenced by factors such as activation energy and enzyme activity.

Enzymes and Catalysts

Enzymes lower the activation energy required for reactions, making them essential catalysts.
Each enzyme is specific to its substrate, fitting into a unique active site.

Temperature and pH for Enzymatic Activity

Enzymes generally function best at around 37 degrees Celsius (body temperature).
Common enzymes include catalase (breaks down hydrogen peroxide) and amylase (breaks down starch).

Additional Concepts

Collagen and hemoglobin are vital proteins in the body.
The pH of common substances illustrates acid-base properties, e.g., vinegar (pH 3-4) and household ammonia (pH 12).

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Description

Explore the fundamental concepts of atoms, subatomic particles, and chemical bonds in this quiz. Understand elements, compounds, isotopes, ions, and the unique properties of water vital to life. Test your knowledge on the basics of chemistry and its building blocks.