ATI TEAS VII Practice A- Chemistry Flashcards
Vitamin B12 is converted to methyl-cobalamin, which is consumed in a reaction where methionine synthase produces the amino acid methionine. Which of the following molecules is the catalyst in this reaction?
A. Vitamin B12
B. Methyl-cobalamin
C. Methionine synthase
D. Methionine
C. Methionine synthase
Explanation:
Methionine synthase has the suffix -ase, which is a standard nomenclature for enzymes. Its name further indicates that it helps to make methionine, so it is a catalyst.
Which of the following terms describes the bonding together of smaller molecules to form larger molecules?
A. Anabolism
B. Catalysis
C. Catabolism
D. Anaphylaxis
A. Anabolism
Explanation:
Anabolism describes the endothermic process by which bonds are formed between molecules to make larger molecules.
After doing a belly flop into a swimming pool, a child says, “The water slapped me.” Which of the following is the property of water that causes the slap?
A. Irregular expansion
B. Hydrogen bonding
C. Cappillary action
D. Hydrophobic exclusion
B. Hydrogen bonding
Explanation:
Hydrogen bonding holds the water molecules tightly together so they cannot disperse easily, increasing tension and causing the slap.
Which of the following statements describes an ion of the isotope Aluminum-27? Use image.
A. The ion has 13 neutrons
B. the atom has a mass number of 14.
C. The atom has 27 electrons.
D. The ion has an electric charge of +3.
D. The ion has an electric charge of +3
Explanation:
Then ion contains 13 protons and 10 electrons. Loosing three electrons will give the ion a charge of +3. The mass number (27) is the sum of protons and neutrons.
Which of the following correctly describes the color change and substance properties for acid-base indicator testing?
A. Blue litmus turns red, indicating the presence of a base with a pH > 7.
B. Red litmus turns blue, showing the presence of an acid with a pH > 7.
C. Blue litmus turns red, indicating the presence of an acid with a pH < 7.
D. Red litmus turns blue, showing the presence of a base with a pH < 7.
C. Blue litmus turns red, indicating the presence of an acid with a pH < 7.
Explanation:
Blue litmus would turn red with an acid, and acids have a pH less than 7.
Which of the following molecules present in blood has the ability to buffer changes in pH?
A. cholesterol
B. Bicarbonate
C. Plasma sugars
D. Circulating salts
B. Bicarbonate
Explanation:
Bicarbonate is the conjugate base of carbonic acid, which is made from water and carbon dioxide, both of which are present in abundance in blood. Therefore, bicarbonate is a buffer in conjunction with carbonic acid.
Which of the following correctly describes physical changes between states of matter?
A. Deposition occurs when the water in a lake changes to ice.
B. Evaporation occurs when candle wax burns to form smoke.
C. Condensation occurs when glue solidifies with exposure to air.
D. Sublimation occurs when dry ice turns into carbon dioxide gas.
D. Sublimation occurs when dry ice turns into carbon dioxide
Explanation:
Sublimation is the conversion of a solid into a gas without passing through a liquid stage. Since carbon dioxide goes from a solid phase to a gaseous phase, this process is sublimation.
According to the abbreviated periodic table above , which of the following compounds is an ionic compound? Use image.
A. PCl3
B. H2O
C. MgF2
D. NH3
C. MgF2
Explanation:
Each magnesium (valence = 2) atom transfers one electron to each of the fluorine (valence = 7) atoms, forming ionic bonds. Molecules formed by the transfer of electrons are called ionic compounds.
Other wrong answers:
A. PCl3
Each of the chlorine (valence = 7) atoms forms a single covalent bond with the phosphorous (valence = 5) atom
B. H2O
Each of the hydrogen (valence = 1) atoms forms a single covalent bond with the oxygen (valence = 6) atom.
D. NH3
Each of the hydrogen (valence = 1) atoms forms a single covalent bond with the nitrogen (valence = 5) atom.
Which of the following is a chemical property, as opposed to a physical property, of water?
A. Ice is less dense than, and floats on , liquid water
B. Water can be decomposed into Hydrogen and oxygen gas
C. Water has a high surface tension due to hydrogen bonding
D. Bonds between water molecules can be broken by heating
B. water can be decomposed into hydrogen and oxygen gas.
Explanation:
Making and breaking of bonds between atoms in a molecule indicate a chemical reaction
Which of these substances will best dissolve in water?
A. CH4
B. CCl4
C. HCl
D. N2
C. HCl
Explanation:
HCl is an ionic compound and dissociates into charged particles called ions. Because water molecules are polar, water is a good solvent for ions.
Wrong answers:
CH4, CCl4, and N2 are nonpolar molecules. Because water molecules are polar, water is not a good solvent for nonpolar molecules.
