How many times stronger is the hydrogen-ion concentration of a pH 4 solution as compared with a pH 9 solution?
0.00001
5
100,000
50
The Correct Answer is C
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.
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Related Questions
Correct Answer is D
Explanation
The opening of potassium channels allows potassium to leave the neuron. Repolarization of a neuron occurs after an action potential when the neuron's membrane potential returns to its resting state. This is achieved by the opening of potassium channels, which allows potassium ions to flow out of the neuron. This movement of positively charged ions out of the neuron helps to restore the negative membrane potential.
A. The inhibition of sodium and potassium pumps would not allow for repolarization because these pumps are necessary for maintaining the resting membrane potential.
B. The opening of sodium channels would cause depolarization, not repolarization.
C. The closing of both sodium and potassium channels would restrict ion movement, but it would not allow for repolarization.
Correct Answer is C
Explanation
The parotid gland is an exocrine gland that secretes saliva into the mouth. Exocrine glands secrete their products into ducts that carry the secretions to the body's surface or into body cavities.
The other options are endocrine glands, which secrete hormones directly into the bloodstream. The pineal gland secretes melatonin, the parathyroid glands secrete parathyroid hormone, and the pituitary gland secretes several hormones that regulate various bodily functions.
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