Ch 2: Quick check questions Flashcards
what kinds of particles make up matter?
Matter is composed of one or more smaller units called atoms.
what is a compound? an element?
Compounds are substances whose molecules have more than one element in them. An element is a pure substance, composed of one of more than a hundred types of atoms that exist in nature.
what is an energy level?
Energy level is the location outside of the nucleus that electrons inhabit (orbitals). The farther an orbital extends from the nucleus, the higher its energy level will be.
What are the 4 kinds of atoms that make up the majority of the human body?
Four kinds of atoms (oxygen, carbon, hydrogen, and nitrogen) make up about 96% of the human body, but there are traces of about 20 other elements in the body.
how is an ion formed?
Ions are formed when the precise balance of (+) and (−) charges is lost, resulting in charged particles (which are either positive or negative).
What is meant by an electrolyte dissociating in water?
Ionic molecules usually dissolve easily in water because water molecules wedge between the ions and force them apart. Molecules that form ions when dissolved in water are called electrolytes.
what is covalent chemical bonding?
when atoms share electrons
why are hydrogen bonds important?
Hydrogen bonds form subtle forces that help a large molecule stay in a particular shape. They may also help hold together neighboring molecules.
how is the charge of an ion indicated in a formula?
The formula of an ion always shows its charge with a superscript plus or minus sign (+ or −) after the chemical symbol. Thus the sodium ion is Na+, and the chloride ion is Cl−. Calcium (Ca) atoms lose two electrons when they form ions, so the calcium ion is written as Ca++.
what is an organic compound?
An organic compound is composed of molecules that contain carbon-carbon covalent bonds, carbon-hydrogen covalent bonds, or both kinds of bonds.
what are the chemical characteristics of water?
Water is essential to life. It is the most abundant compound in the body, found in and around each cell. Its slightly glue-like properties help hold the tissues of the body together. Each water molecule is made up of two hydrogen atoms and one oxygen atom.
What is the difference between dehydration synthesis and hydrolysis?
dehydration synthesis, reactants combine only after hydrogen and oxygen atoms are removed and the leftovers form water.
Hydrolysis, , is the process in which water disrupts the bonds in large molecules, causing them to be broken down into smaller molecules. These two reactions are opposites.
explain the concept of pH
The relative H+ concentration is a measure of how acidic or basic a solution is. The H+ concentration is usually expressed in units of pH. The formula used to calculate pH units gives a value of 7 to pure water. A higher pH value indicates a low relative concentration of H+ – a base. A lower pH value indicates a higher H+ concentration – an acid.
does an acid have a low or high pH? does a base have a low or high pH?
An acid has a low pH, and a base has a high pH.
What is the difference between alkalosis and acidosis? What prevents these conditions from occurring frequently in the body?
Alkalosis is high blood pH, and acidosis is low blood pH. These conditions are both potentially dangerous but rarely occur because of homeostatic mechanisms in the body. These mechanisms are the removal of H+ ions by excretion in the urine, removal of acid by increasing the loss of carbon dioxide (an acid) by way of the respiratory system, and the body’s ability to adjust pH by using buffers that are chemicals in the blood that maintain pH.
