Ch. 2 Learning Objectives

2.15 Describe the causes and consequences of ocean acidification.

Ocean acidification is mainly caused by carbon dioxide gas in the atmosphere dissolving into the ocean. This leads to a lowering of the water's pH, making the ocean more acidic.

2.3 Distinguish between the size, location, and properties of protons, electrons, and neutrons.

- A proton is a subatomic particle with a single positive electrical charge. - An electron is a subatomic particle with a single negative charge. - A neutron is electrically neutral. If an atom were the size of a baseball stadium, the nucleus would be the size of a fly in the center field, and the electrons would be like two tiny gnats buzzing around the stadium. Protons and neutrons are located in an atom's nucleus and electrons are outside of the electron cloud.

2.11 Define and distinguish between heat and temperature. Explain how sweating helps to cool your body.

-Heat describes the transfer of thermal energy between molecules within a system and is measured in Joules. -That's because cooling your body via sweating relies on a principle of physics called "heat of vaporization." It takes energy to evaporate sweat off of your skin, and that energy is heat. As your excess body heat is used to convert beads of sweat into vapor, you start to cool down.

2.1 Define matter, an element, a compound, and a trace element.

-Matter: Anything that occupies space and has mass. -Element: A substance cannot be broken down to other substances by chemical means. -Compound: A substance containing two or more elements in a fixed ratio. -Trace Element: An element that is essential for life but required in extremely minute amounts.

2.14 Explain how acids and bases directly or indirectly affect the hydrogen ion concentration of a solution.

Acids increase the hydrogen ion concentration in a substance and bases decrease it.

2.10-2.13 Describe the special properties of water that make it vital to living systems. Explain how these properties are related to hydrogen bonding.

Because of hydrogen bonds, water has a high boiling point and when it freezes, ice has a lighter density than the liquid because the hydrogen bonds are stable and farther apart.

2.14 Explain how buffers function.

Buffers work by neutralizing any added acid (H+ ions) or base (OH- ions) to maintain the moderate pH, making them a weaker acid or base. Thus the breaking of the buffer is its capacity, or in other words, it is the amount of acid or base, a buffer can absorb before breaking its capacity.

2.10 Define and distinguish between cohesion, adhesion, and surface tension.

Cohesion: refers to the attraction of molecules for other molecules of the same kind, and water molecules have strong cohesive forces thanks to their ability to form hydrogen bonds with one another. Adhesion: The attraction of molecules of one kind for molecules of a different kind, and it can be quite strong for water, especially with other molecules bearing positive or negative charges. Surface tension: "The property of the surface of a liquid that allows it to resist an external force, due to the cohesive nature of its molecules."

2.9 Explain the significance of chemical reactions. Identify the reactants and products of photosynthesis.

During photosynthesis, light energy converts carbon dioxide and water (the reactants) into glucose and oxygen (the products).

2.5 Explain how the electron configuration of an atom influences its chemical behavior.

Electrons move around the nucleus only at certain energy levels, called electron shells. It is the number of electrons in the outermost shell, called the valance shell, that determines the chemical properties of an atom.

2.2 Explain how and why iodine, fluoride, and iron are added to the human diet.

Fluoride is added to the human diet to reduce tooth decay; it is added to drinking water and dental products. Iron is added to the human diet because it is vital for energy processing and for transferring oxygen to your blood; Iron is added to foods such as cereal.

2.16 Explain why the search for extraterrestrial life centers on the search for water.

If life has evolved elsewhere in the universe like ours, then it too would depend on water.

2.3 Define an isotope and explain what makes some isotopes radioactive.

Isotopes of an element have the same number of protons and behave identically in chemical reactions, but have different numbers of neutrons. A radioactive isotope is one in which the nucleus decays spontaneously, giving off particles, and energy.

2.4 Describe the uses and dangers of radioactive isotopes.

Radioactive materials are hazardous. Nuclear radiation can ionize chemicals within a body, which changes the way the cells behave. It can also deposit large amounts of energy into the body, which can damage or destroy cells completely. Radioactive isotopes can sit in the stomach and irradiate for a long time.

2.12 Explain why ice floats

Solid water (Ice) is able to float because it is less dense because of hydrogen bonding.

2.13 Define a solute, a solvent, and a solution.

Solute: the dissolved substance Solvent: A liquid in which substances (or solutes) are dissolved forming a solution Solution: A type of homogenous mixture in which the particles of one or more substances (the solute) are distributed uniformly throughout another substance (the solvent).

2.3 Define the atomic number and mass number of an atom.

The number of protons determines an element's atomic number and is used to distinguish one element from another. Together, the number of protons and the number of neutrons determine an element's mass number.

2.14 Explain the basis of the pH scale.

The pH of a solution is a measure of the concentration of hydrogen ions in the solution. A solution with a high number of hydrogen ions is acidic and has a low pH value. A solution with a high number of hydroxide ions is basic and has a high pH value. The pH scale ranges from 0 to 14, with a pH of 7 being neutral.