Chapter 2 Ions
The formula H2O consists of
a molecule containing two hydrogen atoms and one oxygen atom
Organic substances are distinguished by molecules that ____, whereas inorganic substances are distinguished by molecules that ____
contain carbon; do not contain carbon
The opposite of a decomposition reaction is called _____
synthesis
The atomic weight of an element whose atoms contain 8 protons, 8 elections, and 9 neutrons is
17
The midpoint of the pH scale is pH _____, this is a neutral substance
7
a decomposition reaction can be symbolized by
AB → A + B
which is an example of the molecular formula
H2O
A covalent bond is characterized by
atoms sharing pairs of electrons
An ionic bond is characterized by
being formed by oppositely charged ions, atoms gaining and other losing electrons, oppositely charged atoms being electrically attracted to one another
DNA is
composed of nucleic acids, holding genetic information
The pH scale measures the
concentration of hydrogen ions in solution
The atoms of two different kinds of elements are like to have
different weights
A chemical reaction in which pairs of two compounds trade positions with one another and form two different compounds on the product is a
double displacement or exchange reaction
When atoms combine with other atoms in forming compounds by ionic or covalent bonding, the interactions occur between their (which subsatomic particle?) _____ to become stable
electrons
matter is composed of ______, which are composed of ____
elements, atoms
A polar molecule forms as the result of unequal sharing of electrons between an ionicly bonded compound
false
An acid is defined as an electrolyte that releases hydroxide ions (OH-) in water and an example is sodium hydroxide
false
Ca+, Na+, H+ are ions specifically called anions, not cations
false
The number of protons within an atom of an element is equal to its atomic weight
false
radioactive isotopes have stable nuclei
false
which of the following substances is an element, not a compound?
iron
a cation is formed by
losing an electron, becoming positively charged
which of the following is not an example of an organic substance?
magnesium oxide- MgO, contains Mg and O
An atom of any element on the periodic table is electrically neutral because the number of
negative electrons and positive protons are equal
A solution that contains equal numbers of hydrogen and hydroxide ions would be called
neutral
The atoms of the isotopes of a particular element vary in the number of
neutrons
The most complex of the carbohydrates is ____ which is usually not completely broke down therefore used as fiber in the digestive system
polysaccharides
An enzyme is defined as a
protein that speeds up the rate if a chemical reactions without being changed or depleted
Atomic number is equal to the number of ____ and the atomic weight is equal to the ____
protons and also the number of electrons; number of protons plus neutrons added together
In a ____ reaction just as many products that are being made are being broke down
reversible
A person has alkalosis if the blood pH
rises above 7.45
for an atom to become stable it must have
the outer shell full of electrons
An atom that has gained or lost electrons is called an ion
true
The atomic weight comes from an average of that element's isotopes
true
a salt is defined as a substance formed by the reaction between an acid and a base
true