How many times stronger is the hydrogen-ion concentration of a pH 4 solution as compared with a pH 9 solution?
A. 0.00001
B. 5
C. 100,000
D. 50
The correct answer is c. 100,000. The pH scale is a logarithmic scale, which means that each change of one pH unit represents a tenfold change in the hydrogen-ion concentration. A pH 4 solution has a hydrogen-ion concentration that is 10^5 (or 100,000) times greater than that of a pH 9 solution.
a. 0.00001 is the hydrogen-ion concentration of a pH 9 solution as compared with a pH 4 solution.
b. 5 is the difference in pH units between a pH 4 solution and a pH 9 solution.
d. 50 is not the correct answer.
Therefore, the Correct Answer is C.
More Questions on TEAS 7 Science
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Q #1: A study found two processes, Process A and Process B, to be correlated. Which of the following is true for these processes?
A. The study indicates that Process A causes Process B.
B. The study cannot indicate whether Process A and B have a positive relationship.
C. The study does not indicate a causal relationship between the processes.
D. The study cannot indicate whether Process A and B have a negative relationship.
Answer Explanation
The correct answer is c.
The study does not indicate a causal relationship between the processes. A correlation between two processes means that there is a statistical relationship between them, but it does not necessarily imply causation. In other words, just because two processes are correlated does not mean that one causes the other.
b.The study does not indicate that Process A causes Process B.
b.The study can indicate whether Process A and B have a positive relationship if the correlation is positive.
d. The study can indicate whether Process A and B have a negative relationship if the correlation is negative.
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Q #2: The triple point of a substance is the temperature and pressure at which the substance exists as which of the following?
A. Simultaneously in sol, gel, and plasma phases
B. As a gel with solid and liquid trapped in gas
C. As a sol with gas and solid trapped in liquid
D. Simultaneously in solid, liquid, and gas phases
Answer Explanation
The triple point of a substance is the temperature and pressure at which the substance exists simultaneously in solid, liquid, and gas phases ¹. In thermodynamics, the triple point of a substance is the temperature and pressure at which the three phases (gas, liquid, and solid) of that substance coexist in thermodynamic equilibrium.
The other options are not correct because they do not accurately describe the triple point of a substance. Sol, gel, and plasma are not phases that coexist at the triple.
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Q #3: Which of the following classes of biological molecules includes enzymes?
A. Lipids
B. Vitamins
C. Carbohydrates
D. Proteins
Answer Explanation
Enzymes are a type of protein that catalyze chemical reactions in the body. Proteins are one of the four main classes of biological molecules, along with lipids, carbohydrates, and nucleic acids.
The other options are not classes of biological molecules that include enzymes. Lipids are a class of molecules that includes fats and oils, vitamins are organic compounds that are essential for normal growth and nutrition, and carbohydrates are a class of molecules that includes sugars and starches.
