Learning Outcomes - Week 3

Question 1

Identify the primary elements (by name and symbol) composing the human body.

Answer 1

1. Carbon (C)
2. Hydrogen (H)
3. Oxygen (O)
4. Nitrogen (N)

Question 2

Describe the difference between chemical elements, molecules, and compounds.

Answer 2

An element is a pure chemical substance made of the same type of atom. A molecule is a substance with two or more atoms bonded together. A compound is a substance that contains atoms of two or more different elements.

Question 3

Define ions, cations, anions, electrolytes, and free radicals.

Answer 3

1. Ion: An atom that has a positive or negative charge because is has unequal numbers of protons and electrons.
2. Cations: An ion with a positive charge
3. Anion: An ion with a negative charge
4. An atom or group of atoms with an unpaired electron in the outermost shell.

Question 4

Define a chemical reaction

Answer 4

A reaction in which new bonds form or old bonds break between atoms.

Question 5

Describe the various forms of energy

Answer 5

1. Kinetic energy: the energy of matter in motion
2. Potential energy: the energy stored by matter due to its position
3. Chemical energy: a form of potential energy that is stored in the bonds of compounds and molecules

Question 6

Define metabolism, anabolism, and catabolism

Answer 6

1. Metabolism: the sum of all chemical reactions in the body
2. Anabolism: the sum of all synthesis reactions in the body
3. Catabolism: the sum of all decomposition reactions in the body

Question 7

Compare exergonic and endergonic chemical reactions.

Answer 7

An exergonic reaction releases more energy that it absorbs. An endergonic reaction absorbs more energy than it releases.

Question 8

Explain the role of activation energy and catalysts in chemical reactions

Answer 8

Activation energy is the initial energy needed to start a reaction. Catalysts are chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur.

Question 9

Differentiate the 4 types of chemical reactions: synthesis, decomposition, exchange, and reversible reactions.

Answer 9

1. Synthesis: two or more atoms, ions, or molecules combine to form new and larger molecules
2. Decomposition: large molecules split into smaller atoms, ions, or molecules
3. Exchange: reactions that consist of both synthesis and decomposition reactions
4. Reversible: reactions in which the products can revert to the original reactants

Question 10

Name the properties of water that account for its ability to support life.

Answer 10

1. Solvency
2. Adhesion
3. Cohesion
4. Chemical reactivity
5. Thermal stability

Question 11

Describe inorganic acids, bases, and salts.

Answer 11

Inorganic acids, bases, and salts are known as “electrolytes”, substances that ionize in water.