Test 2 A and P lab

Which of the following is NOT one of the three major types of chemical reactions?

hyperbolic Most chemical reactions exhibit one of three recognizable patterns. They are either synthesis, decomposition, or exchange reactions.

The pH scale __________.

is based on the concentration of hydrogen ions in a solutionis based on the salinity of a solutionranges from 1 to 7 The pH scale, which ranges from 0 to 14, is a logarithmic scale based on the concentration of hydrogen ions in a solution.

Rank the chemical bonds from relatively weakest to strongest.I. IonicII. CovalentIII. Hydrogen

III < I < II Covalent bonds are the strongest because they involve sharing electrons. Ionic bonds are weaker and involve attractions between oppositely charged ions. Hydrogen bonds are the weakest and involve attractions between partial charges.

What is the difference between kinetic and potential energy?

Kinetic energy is energy in action, while potential energy is stored energy. Kinetic energy is energy in action. We see evidence of kinetic energy in the constant movement of the tiniest particles of matter, as well as in larger objects. Potential energy is stored energy, which has the capacity to do work but is not presently doing so.

Which of the following is NOT a difference between a compound and a mixture?

Mixtures are homogeneous while compounds are heterogeneous. Mixtures differ from compounds in several important ways. (1) The chief difference between mixtures and compounds is that no chemical bonding occurs between the components of a mixture. The properties of atoms and molecules are not changed when they become part of a mixture. (2) Depending on the mixture, its components can be separated by physical means—straining, filtering, evaporation, and so on. Compounds, by contrast, can be separated into their constituent atoms only by breaking chemical bonds. (3) Some mixtures are homogenous, while others are heterogeneous. All compounds are homogeneous.

Which of the following statements regarding atoms is true?

The reactivity of an atom is based on the number of electrons in its outer valance shell. can predict whether an atom will be chemically inert or reactive based on the number of electrons in its outermost energy level (valence shell).

Which of the following is NOT one of the three basic steps involved in enzyme activity?

The substrate absorbs chemical energy from the enzyme after binding to its active site. Enzymes do not provide energy to their substrates. In fact, enzymes are completely unchanged by their catalytic role and can act again and again.

Which of the following statements regarding matter is FALSE?

The weight of matter remains constant wherever it is located. The mass of an object is equal to the actual amount of matter in the object, and it remains constant wherever the object is. In contrast, weight varies with gravity. Matter is anything that occupies space and has mass. With some exceptions, it can be seen, smelled and felt. Matter exists in solid, liquid, or gaseous states.

Which of the following is true about lipids?

Triglycerides are composed of three fatty acids and one glycerol and are stable because they do not dissolve in water. The long-term stability of triglycerides makes them important energy storage molecules.

The major function of DNA is to provide the genetic instructions for protein synthesis.

True DNA provides the basic instructions for building every protein in the body. RNA carries out the orders for protein synthesis issued by DNA.

All salts are ionic compounds, but not all ionic compounds are salts.

True Salts are ionic compounds that contain a cation other than H+ and an anion other than OH-.

ATP is an unstable, high-energy molecule that provides body cells with a form of energy that is immediately usable

True ATP is the primary energy-transferring molecule in cells, and it provides a form of energy that is immediately usable by all body cells. Chemically, the triphosphate tail of ATP can be compared to a tightly coiled spring ready to uncoil with tremendous energy when the catch is released. Actually, ATP is a very unstable high-energy molecule because its three negatively charged phosphate groups are closely packed and repel each other.

Which four elements comprise approximately 96% of our body weight?

carbon, oxygen, hydrogen, and nitrogen make up about 96% of our body weight; 20 others are present in the body, some in trace amounts.

When an acid is added to a solution containing a weak base, the weak base will buffer the drop in pH by completely dissociating and accepting all of the hydrogen ions released from the acid.

False Buffers resist abrupt and large swings in the pH of body fluids by releasing hydrogen ions (acting as acids) when the pH begins to rise and by binding hydrogen ions (acting as bases) when the pH drops. Buffers can do this because they consist of a combination of a weak acid and a corresponding weak base. Weak acids and bases dissociate (ionize) partially and reversibly, whereas strong acids and bases dissociate completely and irreversibly.

In a solution, the solute is the substance present in the greatest amount.

False In a solution, the solute is the substance present in lesser amounts. There may be many solutes.

Nonpolar molecules are the result of unequal electron pair sharing.

False Polar molecules are the result of unequal electron pair sharing. Nonpolar molecules are electrically balanced because of the equal sharing of electrons between the atoms of the molecules.

Atomic weight is equal to the number of protons and neutrons in the nucleus.

False The mass number of an atom is equal to the number of protons and neutrons in its nucleus. Atomic weight is a weighted average of the isotopes that exists for an element.

Which of the following is true of protein structure?

Secondary protein structures involve hydrogen bonding between amine and carboxyl groups. Hydrogen bonding between certain amine and carboxyl groups creates alpha helices and beta-pleated sheets.

Which of the following statements about the polarity of covalent bonds is correct?

Small atoms with 6 or 7 valence shell electrons tend to be electronegative. such as oxygen, nitrogen, and chlorine, are electron-hungry. They attract electrons very strongly, a capability called electronegativity.

Which of the following best describes an isotope?

Structurally variant atoms, which have the same number of protons (and electrons), but differ in the number of neutrons they contain. same number of protons and electrons but differ in the number of neutrons they contain.

Which of the following is a FALSE statement about carbohydrates?

The chemical composition of carbohydrates includes two oxygens and one hydrogen for every carbon present The correct ratio is two hydrogens and one oxygen for every carbon.

Water is an important molecule because it __________.

can form hydrogen bonds Because of its polar nature, water is able to form hydrogen bonds. In fact, many of the special properties of water derive from its extensive hydrogen bonding capacity. In addition, water has a high heat capacity and is considered a universal solvent since it dissolves more substances than any other known solvent.

Which of the following is NOT a subatomic particle?

molecule Atoms are comprised of subatomic particles: protons, electrons, and neutrons. Most atoms do not exist in the free state but instead are chemically combined with other atoms. Such a combination of two or more atoms held together by chemical bonds is called a molecule.