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34 terms

Chapter 2

STUDY
PLAY
Minerals are organic elements extracted from the soil by plants
False
Molecules composed of two or more atoms are called compounds.
False
Hydrogen, deuterium, and tritium are three isotopes of hydrogen.
True
Potassium, sodium, and chlorine are trace elements.
False
Ionic bonds break apart in water more easily than covalent bonds do
True
A solution is a mixture composed of two or more substances that are physically blended but not chemically combined.
True
Blood pH is approximately 7.4, which is slightly acidic.
False
The high heat capacity of water makes it a very ineffective coolant.
False
In an exchange reaction, covalent bonds are broken and new covalent bonds are formed.
True
All the chemical reactions in which larger molecules are broken down to smaller ones are called catabolic reactions.
True
The opposite of a dehydration synthesis is a hydrolysis.
True
Unsaturated fatty acids have as much hydrogen as they can carry.
False
A dipeptide is a molecule with two peptide bonds.
False
All amino acids have both a carboxyl group and an amino group attached to a central carbon.
True
ATP is the body's most important form of long-term energy storage.
False
The most abundant element in the human body, by weight, is
Oxygen
Sodium has an atomic number of 11 and an atomic mass of 23. Sodium has
12 neutrons and 11 protons
The chemical properties of an atom are determined by its
Electrons
Sodium, which has an atomic number of 11, will react with chlorine, which has an atomic number of 17. When these two atoms react, both become stable. To become stable, sodium will ____________, while chlorine will ____________.
give up one electron; accept one electron
Consider oxygen, which has an atomic number of 8 and an atomic mass of 16. How many valence electrons does it have?
6
Consider oxygen, which has an atomic number of 8 and an atomic mass of 16. How many valence electrons does it have?
NonPolar covalent
When table salt, sodium chloride (NaCl), is placed in water
Ionic bonds between Na+ and Cl- are broken.
The bonding properties of an atom are determined by its
Electrons
What type of bond attracts one water molecule to another?
A hydrogen bond
Which of these is a cation?
Ca2+
______ account for 98.5% of the body's weight.
Carbon, oxygen, hydrogen, nitrogen, calcium, and phosphorus
Varieties of elements called ________ differ from one another only in number of neutrons and therefore in atomic mass.
Isotopes
When you jump off a high diving board into water, you notice great resistance of water. This resistance is called __________ and is caused by water's great ______.
surface tension; cohesiveness.
Which of these is hydrophobic?
Fat
Consider a mixture of blood, which contains sodium chloride, protein, and cells or formed elements. The sodium chloride is in a(n) ____________, the protein is in a(n) __________, and the cells are in a ____________.
solution; colloid; suspension
Which of these is the most appropriate to express number of molecules per volume?
Molarity
A solution with pH 4 has ______ the H+ concentration of a solution with pH 8.
10,000 times
Which of these has the highest H+ concentration?
lemon juice, pH = 2.3
Blood has a pH ranging from 7.35 to 7.45. Slight deviations from this can cause major problems, even death. You are doing an intense workout, and your skeletal muscle cells are producing metabolic acids such as lactic acid. Your blood pH does not drop significantly in spite of the metabolic acids released into the blood. You maintain a constant blood pH because
the body contains chemicals called buffers that resist changes in pH