Question

11. A student wants to make 12.50 mL of 0.36M HCl solution. She has 6.000M HCl stock solution available to her; how much water should she combine with an appropriate volume of stock solution to complete her dilution?

a. 0.7500 mL

b. 11.75 mL

c. 208.3 mL

d. none of the above

14. Which of the following acids is assumed to dissociate completely in solution? explain.

a. HClO

b. HNO₃

c. HNO₂

d. all of the above

15. When a gas expands (all other factors held constant), which of the following is/are true? explain.

I. work is done by the gas

II. the gas loses heat

III. the temperature of the gas decreases

IV. the internal energy of the gas decreases

a. I only

b. I and III only

c. I, III, and IV only

d. I, II, III, and IV

16. A system gets hotter over a period of time. Which of the following must be true? explain.

a. work has been done on the system

b. the system has absorbed heat

c. the internal energy of the system has increased

d. all of these are true statements

Answer 1

11)

use dilution formula

M1*V1 = M2*V2

Here:

M1 is molarity of solution before dilution

M2 is molarity of solution after dilution

V1 is volume of solution before dilution

V2 is volume of solution after dilution

we have:

M1 = 6.0 M

M2 = 0.36 M

V2 = 12.5 mL

we have below equation to be used:

M1*V1 = M2*V2

V1 = (M2 * V2) / M1

V1 = (0.36*12.5)/6

V1 = 0.75 mL

so, 0.75 mL of stock solution should be used

so,

Volume of water added = V2 - V1

= 12.50 mL - 0.75 mL

= 11.75 mL

Answer: b

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