Basic Chemistry and Water Test

Atoms have positively charged...?

Protons

Atoms have neutral...?

Neutrons

Atoms have negatively charged...?

Electrons

Proton number present equals....?

Atomic number of each element

Neutron number may differ in...?

Different isotopes

Electron number in outer shell determines formation of...?

Chemical bonds

Electron transfer between atoms creates...?

Ions

Electron sharing between atoms creates...

Covalent bonds

Attraction between ions creates...?

Ionic bonds

Unequal sharing of electrons creates..?

Polar covalent bonds

Equal sharing of electrons creates...?

Nonpolar covalent bonds

An example of a polar covalent bond is...?

Water

Water has important qualities due to polarity and...?

Hydrogen bonds

Your body contains the smallest amount of which of the following?
A. Nitrogen
B. Phosphorus
C. Carbon
D. Oxygen
E. Hydrogen

B. Phosphorus

Changing the what of an atom would change it into an atom of a different element?

Number of protons in the nucleus of an atom

A solution of pH 6 contains what than the same amount of solution at pH 8?

100 times more H+

Most of the unique properties of water result from the fact that water molecules are what?

Are polar and form hydrogen bonds

A sulfur atom has 6 electrons in its outer shell. As a result, it forms how many covalent bonds with other atoms?

2

What does it mean if something has a pH of less than 7?

It is acidic

What does it mean if something has a pH of 7?

It is neutral

What does it mean if something has a pH of more than 7?

It is basic

Is solid ice melting into liquid water a chemical reaction?

No

True or False
Table salt, water, and carbon are compounds.

False, carbon is not a compound, it is an element

True or False
The smallest part of an element is a molecule.

False, an atom is the smallest

True or False
A bathtub full of lukewarm water may hold more heat than a teakettle full of boiling water.

True

True or False
If the atoms in a molecule share electrons equally, the molecule is nonpolar.

True

True or False
Ice floats because water molecules in ice are more tightly packed than in liquid water.

False, water molecules in ice are farther apart

True or False
Atoms in a water molecule are held together by the sharing of electrons.

True

True or False
Most Acid precipitation results from the presence of pollutants from aerosol cans and air conditioners.

False, results from burning fossil fuels

True or False
An atom that has gained or lost electrons is called an ion.

True

Why do water molecules form hydrogen bonds?

They are polar

List waters unique properties

-Adhesion
-Cohesion
-High specific heat
-High heat of vaporization
-Solid form is less dense than liquid form
-Universal Solvent

Compare covalent and ionic bonds

A covalent bond forms when atoms complete their outer shells by sharing electrons. Atoms can also complete their outer shells by gaining or losing electrons. This leaves the atoms as ions, with negative and positive charges. The oppositely charged ions are attracted to each other, forming an ionic bond.

What is an acid?

An acid is a compound that donates hydrogen ions (H+) to a solution

What is a base?

A base is a compound that accepts hydrogen ions and removes them from the solution.

How is the acidity of a solution described?

Acidity is described by the pH scale, which measures H+ concentration on a scale of 0 (most acidic) to 14 (most basic)

How can radioactive isotopes be useful?

Useful in medicine and science

What do hydrogen bonds do?

They make water molecules cohesive, creating surface tension and allowing water to move from plant roots to leaves.

Define element

Basic chemical unit that cannot be broken apart by typical chemical processes

Define matter

Anything has has mass and takes up space

Amount of naturally occurring elements?

92

How many elements are required by living organisms?

25

4 important elements to biology?

Carbon
Nitrogen
Oxygen
Hydrogen

Define trace elements

Are essential in minute quantities for proper biological functioning

Example of a trace element

Iodine is a trace element added to food and water to improve health

Define compound

Substance containing two or more different elements in a fixed ratio

Define atom

Element's smallest unit

Define isotope

Atoms with the same atomic number but different atomic mass

Weakest bond?

Hydrogen bond

Strongest Bond?

Covalent bond

Define atomic number

The number of protons that defines an element

Define mass number

The sum of the protons and neutrons in an atom's nucleus

Define adhesive

Two differ t substance attracted to each other

Define cohesive

Tendency of like molecules to stick together

High specific heat?

Amount of energy it takes to change 1 gram to 1 degree C

High heat of vaporization?

Amount of energy it takes to change 1 gram of liquid to a gas

Solid form is less dense than liquid?

When water freezes, water molecules form a crystalline structure maintained by hydrogen bonds.

Universal solvent?

What is capable of dissolving a variety of different substances which is why it is such a good solvent.

Ionic bonds?

Attraction of ions of opposite charge

Double bond?

When two oxygen atoms share two pairs of electrons

Molecule?

Two or more atoms held together by covalent bonds

Electronegativity?

An atoms attraction for its electrons, including shared electrons

Surface tension?

Results from the cohesion of water molecules

Acid precipitation effects what?

The environment