CHAPTER 2 Bio

Which of the following is the definition of the heat of vaporization of water?

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

In a neutral atom, the number of electrons is equal to which of the following?

The atomic number

What type of bond is formed when 2 atoms share one or more pairs of valence electrons? Multiple choice question.

covalent

A group of atoms held together by chemical bonds in a stable association is called which of the following?

molecule

Atomic number refers to the number of ______ in an atom.

protons

The atomic mass of an atom is equal to the sum of the masses of its _____ and ______.

Blank 1: protons Blank 2: neutrons

The three main types of subatomic particles are ______, ______, and _______.

Blank 1: protons or proton Blank 2: neutrons or neutron Blank 3: electrons or electron

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

Blank 1: redox, reduction-oxidation, or oxidation-reduction

When 1 g of sugar is dissolved in 500 mL of water, the sugar is called the ______ and water is called the _______.

Blank 1: solute Blank 2: solvent

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

Blank 1: temperature or heat

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

Blank 1: water Blank 2: fructose or sugar

Match each subatomic particle with its electrical charge. - 0 = - +1 = - -1 =

0 = neutron +1 = proton -1 = electron

An atom has 8 protons, 9 neutrons, and 8 electrons. This atom has an atomic number of ______, an atomic mass of ______, and an overall charge of ______.

8; 17; 0

An atom has 8 protons, 9 neutrons, and 8 electrons. This atom has an atomic number of ______, an atomic mass of ______, and an overall charge of ______. Multiple choice question.

8; 17; 0

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

Electrons

The amount of energy required to change 1 g of a substance from a liquid to a gas is called which of the following?

Heat of vaporization

What is the temperature of a substance a measure of?

How fast its molecules are moving

_______ atoms usually have no neutrons.

Hydrogen

Which property of water strongly affects the overall shape of many biological molecules, such as protein, and DNA?

Hydrophobic exclusion

What does it mean when we say water is adhesive?

It is attracted to other polar molecules and ions.

In living systems, which of the following catalyze almost every chemical reaction necessary for life?

enzymes

If two atoms are joined by a polar covalent bond, the shared electrons will tend to stay closer to the atom with ______.

higher electronegativity

The negative logarithm of the hydrogen ion concentration of a solution is known as its ______.

pH

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

positive

A hydrogen ion, formed during the dissociation of water, has a charge of which of the following?

+1

Molecules that are more polar tend to have which of the following characteristics?

- A higher specific heat - A higher heat of vaporization

Which of the following are subatomic particles?

- Electrons - Protons - Neutrons

Which subatomic particles are located in the nucleus of an atom?

- Protons - Neutrons

What is the charge of a hydroxide ion?

-1

Arrange the following states of water in order from most dense to least dense (start with most dense at the top). - liquid - solid - water

1. liquid 2. solid 3. gas

An atom has 11 protons, 12 neutrons, and 10 electrons. This atom has an atomic number of ______, an atomic mass of ______, and an overall charge of ______.

11; 23; +1

An electrically neutral atom has an atomic number of 11 and an atomic mass of 23. This atom has ______ protons, ________ neutrons, and _______ electrons.

Blank 1: 11 or eleven Blank 2: 12 or twelve Blank 3: 11 or eleven

An electrically neutral atom has an atomic number of 6 and an atomic mass of 14. This atom has ______ protons, ______ neutrons, and _____ electrons

Blank 1: 6 or six Blank 2: 8 or eight Blank 3: 6 or six

Generally speaking, an atom is made of a central _______ which is surrounded by orbiting ________.

Blank 1: nucleus Blank 2: electrons or electron cloud

Among subatomic particles, a(n) ______ has a charge of +1, a(n) _______ has a charge of -1, and a(n) ______ has no charge.

Blank 1: proton or protons Blank 2: electron or electrons Blank 3: neutron or neutrons

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?

Hydrophobic exclusion

Where are the valence electrons of an atom found?

In the outermost energy level only

Which subatomic particles determine the atomic mass of an atom?

Protons and neutrons

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?

The polar nature of water molecules

A neutral atom has no net electrical charge. Why?

There are equal numbers of protons and electrons in the atom.

If two atoms belong to the same element, which of the following must be true?

They must have the same number of protons.

When NaCl is formed, ______.

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

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

adhesion

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

electrons

Redox reactions involve a transfer of ______ from one atom to another.

electrons

Subatomic particles called ________ can be found at various distances from the nucleus (please only write the name of the particle without specifying its charge or other properties).

electrons

The chemical behavior of an atom is determined by the number and configuration of its ______.

electrons

The green spheres (indicated by arrows) in the simple "Bohr model" of atoms shown here represent ______.

electrons

A substance that cannot be broken down into simpler substances by ordinary chemical means is called a(n) ______.

elements

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

enzymes

______ atoms always have one proton.

hydrogen

The atoms in NaCl are held together by what type of bond? Multiple choice question.

ionic

Solid water is ______ dense than liquid water

less

Anything that has mass and occupies space is defined as ______.

matter

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

matter

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

Substances or mixtures of substances known as buffers, act in living things to resist changes in _______.

pH

Atoms of the same element always have the same number of _____ in the nucleus, and this number is unique for that element.

protons

Atoms of the same element always have the same number of ______ in the nucleus, and this number is unique for that element.

protons

In the simple "Bohr model" of atoms shown here, the tan spheres (identified by arrows) represent which of the following?

protons

The atomic number of an element refers to the number of ______ in the atoms of that element. Multiple choice question.

protons

Atoms of different chemical elements can be differentiated based on the number of ______.

protons in the nucleus

The pH of a solution is defined as _______.

the negative logarithm of the hydrogen ion concentration in the solution

The number and configuration of electrons determines an element's _______.

chemical properties

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

cohesive

A(n) _______ bond is formed when 2 atoms share one or more pairs of valence electrons.

covalent

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?

covalent

What do we call a substance that cannot be broken down into simpler substances by ordinary chemical means?

An element

If two atoms have the same number of protons in their nucleus, you can conclude for sure that they ______.

are atoms of the same element

Water is cohesive because water molecules are ______.

attracted to each other

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

buffer

Valence electrons and their interactions determine the _______ properties of an element.

chemical