Chapter 2 principles of biology

Which of the following is the definition of the heat of vaporization of water? Multiple choice question. The temperature to which water has to be heated in order to produce 1 g of water vapors in 1 hour The amount of energy needed to raise the temperature of water by 1 °C The amount of energy needed to change 1g of water from a liquid to a gas.

The amount of energy needed to change 1g of water from a liquid to a gas.

Redox reactions involve a transfer of _____________________from one atom to another.

electrons

Electrons in outer, unfilled energy levels are known as _____________________electrons.

valence

What are catalyst?

Activator

electrons in discrete orbits

Bohr model

CHNOPS main components organic molecules

Carbon hydrogen nitrogen oxygen phosphorus sulfer

more protons than electrons = net positive charge

Cation

Molecules are group of atoms held together in a stable association

Chemical bonds

What involves the formation of breaking of chemical bonds?

Chemical reactions

In situ

Chemically made

polarity of water allows water molecules to be attracted to one another

Cohesion

water molecules stick to other water molecules by hydrogen bonding

Cohesion

How many covalent bonds are there?

Single covalent bond- hydrogen gas double covalent bond - oxygen gas triple covalent bond - nitrogen gas

A hydrogen ion, formed during the dissociation of water, has a charge of which of the following? Multiple choice question. -2 +2 -1 +1

+1

Chemical reaction is based on the

- Tempature - concentration of reactants and products -catalysts - show up and dissolve and activator

Molecules that are more polar tend to have which of the following characteristics? Multiple select question. A lower specific heat A higher specific heat A lower heat of vaporization A higher heat of vaporization

A higher specific heat A higher heat of vaporization

- water molecules stick to other polar molecules by hydrogen bonding

Adhesion

fewer protons than electrons = net negative charge

Anion

What is formed when atoms share 2 or more valence electrons?

Covalent bond results in no net charge satisfies octet rule , no unpaired electrons strength of covalent bond depends on the number of shared electrons . many biological compounds are composed of 2 of more

An atom is composed of a central nucleus which is surrounded by which orbiting particles? Multiple choice question. Electrons Protons Neutrons Ions

Electrons

time it takes for one-half of the atoms in a sample to decay

Half life

What is the temperature of a substance a measure of? Multiple choice question. How many hydrogen bonds are formed between its molecules The adhesive properties of its molecules How fast its molecules are moving

How fast its molecules are moving

Life is inextricably tied to water •Single most outstanding chemical property of water is its ability to form what type of bond?

Hydrogen bonds

Consider a large protein molecule that has some parts that are highly hydrophobic. When placed in a water solution, the protein folds in a globular shape, such that all the hydrophobic portions are inside the molecules, away from water. This is an example of which of the following? Multiple choice question. Hydrophobic exclusion Hydration shell formation Hydrogen bond formation between non-polar regions

Hydrophobic Exclusion

Which property of water strongly affects the overall shape of many biological molecules, such as protein, and DNA? Multiple choice question. High heat of vaporization HIgh specific heat Hydrophobic exclusion Capillary action

Hydrophobic exclusion

Which property of water strongly affects the overall shape of many biological molecules, such as protein, and DNA? Multiple choice question. Capillary action High specific heat Hydrophobic exclusion High heat of vaporization

Hydrophobic exclusion

Where are the valence electrons of an atom found? Multiple choice question. In the outermost energy level only In all energy levels In the 2p orbitals only In the innermost energy level only

In the outermost energy level only

elements have all eight electrons

Inert nonreactive

The atoms in NaCl are held together by what type of bond? Multiple choice question. Ionic Covalent Hydrogen van der Waals attraction

Ionic

The toughest ion to break is a?

Ionic bond

What is formed by the attraction of oppositely charged ions. gain or loss of electrons forms ion

Ionic bond Na atom loses an electron to become Na + cl atom atom gains an electron to become Cl- Opposites charges attract so that Na+ and Cl- remain associated as an ionic compound

Opposites attracting to each other?

Ionic bonding

Atoms of a single element that possess different numbers of neutrons

Isotopes

What does it mean when we say water is adhesive? Multiple choice question. It is attracted to other polar molecules and ions. It is attracted to nonpolar molecules. It is attracted to each other. It is held together by strong covalent bonds.

It is attracted to other polar molecules and ions

What does it mean when we say water is adhesive? Multiple choice question. It is attracted to other polar molecules and ions. It is attracted to nonpolar molecules. It is attracted to each other. Reason: The property of water molecules to attract each other is called cohesion. It is held together by strong covalent bonds.

It is attracted to other polar molecules and ions.

rrange the following states of water in order from most dense to least dense (start with most dense at the top). Instructions Choice 1 of 3. Liquid, solid gas Choice 2 of 3. Solid liquid, gas Choice 3 of 3. Gas , solid, liquid

Liquid, solid, gas

Refers to amounts of substance

Mass

Products

Molecules resulting from reaction.

Gain an electron =

Negative

What is released when we die?

Nitrogen

atoms tend to establish completely full outer energy levels

Octet rule

Inorganic = no carbon

Organic = carbon

Reactants =

Original molecule

Substances or mixtures of substances known as buffers, act in living things to resist changes in Blank______. Multiple choice question. Salt concentration Pressure Temperature pH

Ph

Electron loses

Positive

Water has several properties important to life: high specific heat, high heat of vaporization, lower density in solid form (ice), ability to act as a solvent and to organize nonpolar molecules. What explains these properties of water? Multiple choice question. The polar nature of water molecules The presence of two hydrogen atoms in each water molecule The high electronegativity of hydrogen atoms The small size of water molecules

The polar nature of water molecules

What is the charge of a hydroxide ion? Multiple choice question. -2 -1 +2 +1

Water dissociates into a hydrogen ion (charge +1) and a hydroxide ion (charge -1). -1

refers to force gravity exerts on substance

Weight

Are reactions reversible?

Yes

When NaCl is formed, ______. Multiple choice question. sodium and a chlorine atom both gain an electron a sodium atom loses an electron, while a chlorine atom gains an electron a sodium and a chlorine atom both lose an electron a chlorine atom loses an electron, while a sodium atom gains an electron

a sodium atom loses an electron, while a chlorine atom gains an electron

The attraction of water to other polar substances is called ___________________.

adhesion

The attraction of water to other polar substances is called _________________________.

adhesion.

The number and configuration of electrons determines an element's __________________. Multiple choice question. chemical properties radioactivity isotopic properties

chemical properties

Because polar water molecules attract each other, water is said to be _____________________.

cohesive

Water consists of one oxygen atom joined to two hydrogen atoms by two single, polar ________________________bonds.

covalent

Water consists of one oxygen atom joined to two hydrogen atoms by what type of bonds? Multiple choice question. Hydrogen Covalent Ionic

covalent

Subatomic particles called ____________________can be found at various distances from the nucleus

electrons

The chemical behavior of an atom is determined by the number and configuration of its Blank______. Multiple choice question. isotopes neutrons protons electrons

electrons

In living organisms, almost all chemical reactions are catalyzed by protein catalysts called ______________________.

enzymes

In living systems, which of the following catalyze almost every chemical reaction necessary for life? Multiple choice question. Enzymes Products Substrates Reactants

enzymes

Nonpolar covalent bonds=

equal sharing of electrons Ex. ch

The amount of energy required to change 1 g of a substance from a liquid to a gas is called which of the following? Multiple choice question. Condensation constant Heat of vaporization Enthalpy Vaporization energy

heat of vaporzation

If two atoms are joined by a polar covalent bond, the shared electrons will tend to stay closer to the atom with Blank______. Multiple choice question. lower atomic mass lower electronegativity more protons in the nucleus higher electronegativity

higher electronegativity

If two atoms are joined by a polar covalent bond, the shared electrons will tend to stay closer to the atom with Blank______. Multiple choice question. lower electronegativity higher electronegativity lower atomic mass more protons in the nucleus

higher electronegativity

Consider a large protein molecule that has some parts that are highly hydrophobic. When placed in a water solution, the protein folds in a globular shape, such that all the hydrophobic portions are inside the molecules, away from water. This is an example of which of the following? Multiple choice question. Hydrogen bond formation between non-polar regions Hydration shell formation Hydrophobic exclusion

hydrophobic exclusion

The atoms in NaCl are held together by what type of bond? Multiple choice question. Covalent Hydrogen van der Waals attraction Ionic

ionic

Solid water is _________________dense than liquid water.

less

Anything that has mass and occupies space is defined as _____________. weight energy matter atom

matter

_____________________________can be defined as any substance that has mass and occupies space.

matter

A group of atoms held together by chemical bonds in a stable association is called which of the following? Multiple choice question. Ion Molecule Crystal Isotope

molecule

A(n) _____________________ is made of two or more atoms held together by chemical bonds in a stable association. The atoms may or may not belong to the same element.

molecule

Which subatomic particles are located in the nucleus of an atom? Neutrons Ions Reason: Ions are atoms that have lost or gained one or more electrons. Electrons Reason: Electrons are found in orbitals surrounding the nucleus. Protons

neutrons and protons

Which of the following are subatomic particles? Multiple select question. Orbitals Neutrons Electrons Protons Ions

neutrons, electrons, and protons.

Generally speaking, an atom is made of a central _______________________which is surrounded by orbiting _________________

nucleus and electrons

The negative logarithm of the hydrogen ion concentration of a solution is known as its Blank______. Multiple choice question. pH buffering capacity acidity

ph

If two atoms are joined by a polar covalent bond, the atom with the lower electronegativity will have a partial ___________________charge.

positive

Atomic number refers to the number of _____________________in an atom.

protons

The atomic number of an element refers to the number of Blank______ in the atoms of that element. Multiple choice question. orbitals neutrons electrons protons

protons

Which subatomic particles are located in the nucleus of an atom? Multiple select question. Protons Neutrons Ions Electrons

protons and neutrons

The three main types of subatomic particles are ____________________,_______________________ , and ____________________.

protons, neutrons, and electrons.

Chemical reactions that involve a transfer of electrons from one atom to another are called ________________________

redox

When 1 g of sugar is dissolved in 500 mL of water, the sugar is called the ___________________and water is called the ______________________.

solute; solvent

The of a substance is a measure of how rapidly its individual molecules are moving_______________________.

temperature or heat

The pH of a solution is defined as ______. Multiple choice question. the negative logarithm of the hydrogen ion concentration in the solution the logarithm of the hydrogen ion concentration in the solution the negative hydrogen ion concentration in the solution

the negative logarithm of the hydrogen ion concentration in the solution

When 1 g of fructose is dissolved in 500 mL of water, __________________is the solvent and ________________________ is the solute.

water, fructose or sugar

Four elements make up 96.3% of human body weight

carbon, hydrogen, oxygen, nitrogen

Electrons _______________from nucleus have more energy

Farther

Polar covalent bonds =

Unequal sharing of electrons ex. H2O2 H20

Water is cohesive because water molecules are ________________________. Multiple choice question. attracted to ions attracted to each other held together by strong covalent bonds attracted to other (not water) polar molecules

attracted to each other Cohesive refers specifically to the fact that water molecules tend to be attracted to other molecules. The tendency of water molecules to be attracted to other (not water) polar molecules is called adhesion.

A(n __________________________ is a substance or a mixture of substances that act to resist changes in pH.

buffer

A(n) ______________________ ,is a substance or a mixture of substances that act to resist changes in pH.

buffer, buffer solution