Chapter 2 SmartBook

What is the charge of a hydroxide ion?

-1

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

-nucleus -electrons, electron cloud, or electron

The three main types of subatomic particles are

-protons or proton -neutrons or neutron -electrons or electron

The angle between the two O-H covalent bonds in a molecule of water is how many degrees (to the tenth place)?

104.5

The angle between the two bonds that hold a water molecule together is approximately ______.

104.5 degrees

The defining feature of organic compounds is the presence of which of the following?

A backbone of carbon atoms

How do catalysts work?

A catalyst shortens the time needed to reach equilibrium.

Which of the following bonds involves the sharing of one or more pairs of electrons?

A covalent bond

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

A higher heat of vaporization A higher specific heat

Hydrophobic substances tend to do which of the following?

Aggregate together when mixed with water in order to minimize contact with water Repel water Assume shapes that minimize contact with water

Less dense as a solid than as a liquid

Aquatic organisms can survive below the frozen surface of ponds and lakes.

Which of the following occurs because solid water is less dense than liquid water?

Aquatic organisms can survive in liquid water below the frozen surface of ponds and lakes. Bodies of water freeze from the top down. Ice floats.

Which of the following best describes how temperature affects the rate of a chemical reaction (assume care has been taken that the temperature is not too high as to destroy the reactants)?

As temperature increases, the reaction rate increases.

hydrogen bond

Attraction between a covalently bound H atom with a slight positive charge and another covalently bound atom with a slight negative charge

ionic bond

Attraction between oppositely charged atoms

What do we call the ability of water to rise inside a tube of narrow diameter against the pull of gravity?

Capillary action

The four most abundant elements in living organisms are ______, ______, ______, and _____.

Carbon Oxygen Nitrogen Hydrogen

What do we call a substance composed of atoms of more than one element that are held together by chemical bonds?

Compound

Water consists of one oxygen atom joined to two hydrogen atoms by what type of bonds?

Covalent

An atom is composed of a central nucleus which is surrounded by which orbiting particles?

Electrons

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

Enzymes

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

Choose the four most abundant elements in living organisms.

Hydrogen Nitrogen Oxygen Carbon

_____ atoms usually have no neutrons.

Hydrogen, H, or Protium

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

Hydrophobic exclusion

Of the following list of bonds and interactions, which one is the weakest?

Hydrophobic interaction

Water tends to repel or exclude which of the following?

Hydrophobic molecules Nonpolar molecules

Regarding ionic compounds, which is more often found in living systems?

Individual ions dissolved in water

Deficiency for which trace element can lead to an enlargement of the thyroid gland and the formation of a goiter?

Iodine

Typically, as the temperature increases, what happens to the rate of a chemical reaction?

It also increases.

What does it mean when we say water is adhesive?

It is attracted to other polar molecules and ions.

As the concentration of reactants increases, so do the collisions between them, which causes which of the following?

It speeds up the chemical reaction.

Solubility

Many types of ions and molecules move freely in cells, permitting a diverse array of chemical reactions.

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

Molecule

Compared to covalent bonds, hydrogen bonds are which of the following?

Much weaker

Which of the following represents the molecules of a compound?

NH3

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

Neutrons, Protons

Can a catalyst change the equilibrium of a reaction?

No

hydrophobic interaction

Nonpolar regions of a molecule are forced together in order to minimize contact with water molecules

High heat of vaporization

Organisms sweat or pant to cool themselves.

Cohesion

Plant leaves pull water up from the roots.

In the simple "Bohr model" of atoms shown here, the spheres that are identified by arrows represent which of the following?

Protons

Which of the following are subatomic particles?

Protons Neutrons Electrons

covalent bond

Sharing of electrons

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

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

Why does the rate of a reaction increase as the concentration of reactants increases?

The reactants collide with each other more frequently.

Why does water rise inside a glass tube with a narrow diameter (a capillary)?

There are electrical charges on the surface of the glass.

Which of the following describes hydrogen bonds?

They are about 5 - 10% as strong as covalent bonds.

Hydrogen bonds are important for which reasons?

They play a key role in determining the properties of water. They help maintain the structure of DNA and proteins.

Elements, such as zinc and iodine, which are found in very small amounts in living things, but play crucial roles in biological processes, are known as which of the following?

Trace elements

Which of the following explains why water rises inside a capillary glass tube?

Water molecules adhere to the surface of the glass.

High specific heat

Water stabilizes the temperature of organisms and the environment.

Many animals have adapted to cool themselves by sweating. Which property of water allows for this adaptation?

Water's high heat of vaporization

The evaporation of water from body surfaces can significantly cool an organism. This is due to what property of water?

Water's high heat of vaporization

van der Waals attraction

Weak attraction between atoms due to oppositely polarized electron clouds

How does water's high heat of vaporization affect living organisms?

When your body is wet, you feel cooler than when your body is dry. Many organisms sweat or pant in order to cool themselves.

The attraction of water to other polar substances is called

adhesion or adhesive

Chemical bonds are broken and new bonds are formed during a(n) _____ _____.

chemical reaction

A chemical reaction involves the breaking and formation of

chemical bonds

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 or cohesion

Water consists of one oxygen atom joined to two hydrogen atoms by two single ______ bonds.

covalent

Rank the following bonds and interactions in order from strongest to weakest starting with the strongest at the top. When ranking the bonds, assume that they occur in a biological system, i.e. chemical compounds are dissolved in water.

covalent bond ionic bond hydrogen bond hydrophobic interaction van der waals attraction

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 Reason: The atom on the left has one tan sphere and no purple spheres in the nucleus. Therefore, tan must represent protons and purple neutrons because all atoms must have at least one proton.

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 or electron

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

enzymes

The attraction between the partially negative oxygen atom of one water molecule and the partially positive hydrogen atom of another water molecule is called a(n) ______ bond.

hydrogen

The relatively weak, but numerous _______________ bonds that form between a water molecule and other molecules (including other water molecules) play a key role in determining the properties of water (please spell the name of the bonds, no abbreviations).

hydrogen

_____ atoms always have one proton.

hydrogen or H

Substances that attract water are called ________________ ("water-loving") while substances that repel water are called ________________ ("water-fearing").

hydrophilic hydrophobic

The tendency of nonpolar molecules to aggregate together in water is known as _________________ exclusion.

hydrophobic

Catalysts _____ the rate of a reaction without being altered themselves.

increase

In living systems, ionic compounds generally exist as

individual ions

During capillary action, water rises up a capillary tube. The diameter of the capillary tube is _____.

inversely proportional to the height of the water column in it

Fish and other animals can survive at the bottom of a lake during winter because ice is ____________dense than liquid water.

less

Solid water is __________ dense than liquid water.

less

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

liquid, solid, gas

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

matter

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

matter or 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

During capillary action, the water will rise higher in a ______.

narrower capillary tube

The oxygen atom in a water molecule carries two partial _____ charges while each hydrogen atom carries a partial _____ charge.

negative, positive

Water tends to repel or exclude ______________ molecules.

nonpolar, hydrophobic, non-polar, or non polar

A hydrogen bond can form between the partially negative _______________ atom of one water molecule and the partially positive_______________ atom of another water molecule.

oxygen, hydrogen

Water carries two partial negative charges on the _____ atom and two partial positive charges, one on each _____ atom. Please spell the entire names of the atoms.

oxygen, hydrogen

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

pH

By convention, when writing a chemical equation the _____ are listed on the left side of the arrow and the _____ are listed on the right side of the arrow.

reactants, products

During a chemical reaction, the substances we start out with are called ______________________ and the substances we end up with are called ________________________.

reactants, products

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

solute solvent

Because of the many hydrogen bonds that form between its molecules, water has a very high _________________ ____________________. This allows small insects to "walk on water."

surface tension

The property of ______ ________ is a measure of how difficult it is to stretch or break the surface of a liquid.

surface tension

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

temperature or heat

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

water, fructose or sugar

Organic molecules are relatively complex molecules that contain a backbone of _____ atoms

carbon or C

A(n) _____ is any substance that increases the rate of a reaction without being altered itself.

catalyst

The ability of water to rise inside a tube of narrow diameter against the pull of gravity is called_____________action.

capillary

Water is cohesive because water molecules are ______.

attracted to each other