Need help! thank you in advance! QUESTION 7 You add 3 mL of 6 M HCI to 1 L of wa

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Need help! thank you in advance!

QUESTION 7 You add 3 mL of 6 M HCI to 1 L of water. What is the new pH? O A. 12.25 O B. 1.00 C.1.75 O D. 2.15 QUESTION 8 Theobromine is a bitter purine derivative found in the cacao plant that is partly responsible for the flavor of dark chocolate. Using the structure provided below, and the purine numbering system, which nitrogens are bonded to methyl groups? Theobromine.pdf O A. N3, N7 B. N3, N9 O C. N7, N9 D. N1, N7 QUESTION 9 Which of the following is NOT true regarding the hydrophobic effect? O A. It is due to attractive forces between hydrophobic molecules. B. It is entropically driven. O C. It is due to water's tendency to hydrogen bond, which is stronger than the hydrophobic interactions between nonpolar molecules. O D. t is the reason why amphipathic molecules tend to form micelles in water

Explanation / Answer

7) Volume of HCL = 3ml = 0.003 L

Molarity of HCL = 6 M

Hence, number of moles of HCL = Molarity * Volume = 0.003*6 = 0.018 moles

Volume of water added = 1 L

Total volume = 1 + 0.003 L = 1.003 L

Now new molarity of HCL = n/V = 0.018 /1.003 = 18 /1003 M

1 mole of HCL produces 1 mole of H+ ions

So concentration of H+ ions = 18/1003 M

New pH = -log[H+] = - log (18/1003) = 1.746

New pH = 1.75 (approx).

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