Farmers who raise cotton once used arsenic acid, H3AsO4, as a defoliant at harvest time. Arsenic acid is a polyprotic acid with Ka1 = 2.5 × 10–4, Ka2 = 5.6 × 10–8, and Ka3 = 3 × 10–13. Suppose that in your lab, you have a small sample of sodium dihydrogen arsenate, NaH2AsO4. It is a colorless (clear) solid with very low solubility in water at room temperature. When it does dissolve appreciably at an elevated temperature, it forms NaH2AsO4(aq) → Na+(aq) + H2AsO4–(aq).

On the product side of the equation, aqueous dihydrogen arsenate (H2AsO4–) has a Ka of 5.6 × 10–8 which has already been mentioned above (as Ka2). Yet, since H2AsO4– itself can accept a proton (H+), it can act as a weak base as well. Calculate its Kb given Ka of H3AsO4 to be 2.5 × 10–4 (Ka1). Is Ka or Kb greater for H2AsO4–?

A. Kb of H2AsO4– = 3.0 × 10–2 and so its Kb > Ka

B. Kb of H2AsO4– = 2.5 × 10–4 and so its Kb > Ka

C. Kb of H2AsO4– = 4.0 × 10–11 and so its Ka > Kb

D. Kb of H2AsO4– = 5.6 × 10–8 and so its Ka = Kb

E. Kb of H2AsO4– = 1.8 × 10–7 and so its Kb > Ka

Follow the steps provided in the simulation to add water to the graduated cylinder, select one of the three samples (copper, silver, or gold), set its mass to the values given in the statements below, and calculate its density. here is a summary of the steps required: add water by clicking and holding prepare a known volume of water button. until the desired volume of water has been added. if more than the desired volume is added, click the reset button. button and redo the procedure. a single click will add about 21.0 ml of water. to set the mass, click and hold weigh out metal button. until the desired amount of metal is added to the weighing pan. once the desired mass of the metal is added, release the button. transfer the metal to water and then click on calculate density button. to see how the density is calculated using water displacement to measure the volume of the solid. to save time you can approximate the initial volume of water to â±1 ml and the initial mass of the solid to â±1 g. for example, if you are asked to add 23 ml of water, add between 22 ml and 24 ml. which metals in each of the following sets will have equal density? check all that apply.

6. what does the symbol ah stand for? o one calorie given off by a reaction the specific heat of a substance the heat capacity of a substance the heat of reaction for a chemical reaction

Select the word from the list that best fits the definition the nuclear family into which a person is born or adopted.