Which one of the following is the weakest acid? A) HF (Ka = 6.8 × 10-4) B) HClO (Ka = 3.0 × 10-8) C) HNO2 (Ka = 4.5 × 10-4) D) HCN (Ka = 4.9 × 10-10) E) Acetic acid (Ka = 1.8 × 10-5)
The answer is D) HCN because it has the lowest Ka value. The Ka value or the acid ionization constant helps determine whether an acid is weak or strong. The Ka value can be thought of like the equilibrium constant and a larger value favors the forward reaction. As a result, a large Ka value will favor the forward reaction which would mean more H+ protons are being formed but a small (but positive) Ka value means it favors the forward reaction but not by much. Therefore, a small Ka value is a weak acid.
What organelle supplies the most energy to the cell? A) Cytosol B) Mitochondria C) Endoplasmic Reticulum D) Nucleus
The answer is B) because the Cytosol is not an organelle. The remaining answer choices are B, C, and D. The Endoplasmic Reticulum is involved in protein synthesis but does not make ATP (the primary energy source for cells). The Nucleus contains the genetic information for the cell and does not provide energy to the cell. Cellular respiration takes place in the Mitochondria and ATP is formed.
Solve for X: 1/5X+1/3X=1
When approaching this kind of problem, I would first make the problem easier by removing the fractions. By multiplying each number by a number that both fractions share in common. 1/5X (times 15) + 1/3X (times 15) = 1 (times 15) This should result in: 3X+5X=15 8X=15 X=15/8=1.875hrs