Question

identify the choice that best completes the statement or answers the question.

1. which of the following contains sodium:

a. h₂o
b. nacl
c. n₂
d. ch₄
e. h₂so₄

1. an atom with 11 protons, 12 neutrons, and 10 electrons is a(n):

a. molecule
b. anion
c. cation
d. isotope
e. radioisotope

1. which of the following is classified as an inorganic compound:

a. glucose
b. triglyceride
c. water
d. protein
e. steroid

1. the most abundant element in the human body is:

a. carbon
b. oxygen
c. hydrogen
d. nitrogen
e. calcium

1. which of the following leads to an increase in the rate of a chemical reaction:

a. increased temperature
b. large particle size
c. lack of catalysts
d. decreased temperature
e. few particles

1. atomic mass is equivalent to the number of ______ in an atom.

a. protons
b. neutrons
c. electrons
d. protons and electrons
e. protons and neutrons

Explanation:

1. Sodium has the chemical symbol Na. In NaCl (sodium - chloride), sodium is present. H₂O is water, N₂ is nitrogen gas, CH₄ is methane, and H₂SO₄ is sulfuric acid, none of which contain sodium.
2. An atom with 11 protons is sodium. With 11 protons and 10 electrons, it has a net positive charge of +1. Cations are positively - charged ions. Anions are negatively - charged, molecules are groups of atoms bonded together, isotopes have the same number of protons but different numbers of neutrons, and radioisotopes are unstable isotopes.
3. Organic compounds contain carbon - hydrogen bonds (except for some simple carbon - containing compounds like carbonates). Water (H₂O) is an inorganic compound. Glucose (C₆H₁₂O₆), triglycerides, proteins, and steroids are organic compounds.
4. Oxygen is the most abundant element in the human body by mass, making up about 65% of the body's mass.
5. An increase in temperature generally increases the rate of a chemical reaction. Larger particle size decreases the reaction rate as it reduces the surface area available for reaction. Lack of catalysts usually slows down reactions, decreased temperature slows down reactions, and fewer particles mean fewer collisions and a slower reaction rate.
6. Atomic mass is approximately equal to the sum of the number of protons and neutrons in an atom. Electrons have a very small mass compared to protons and neutrons and do not contribute significantly to the atomic mass.

Answer:

1. B. NaCl
2. C. cation
3. C. water
4. B. oxygen
5. A. increased temperature
6. E. protons and neutrons