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The pH scale for acidity is defined by pH = − log₁₀[H⁺] where [H⁺] is the concentration of hydrogen ions measured in moles per liter (M). A solution has a pH of 2.55. Find the hydrogen ion concentration.
Answer: -
0.003 M
Explanation: -
pH = − log₁₀[H⁺]
Thus the hydrogen ion concentration [H⁺] = 
= 
= 0.003 M
Answer is B because C and D make has nothing to do with the question and A isn’t it
Answer:
C. HCI(g)
Explanation:
The following equation between hydrogen gas (H2) and oxygen gas (O2) is given below:
H2(g) + Cl2(g) ►
Based on these unbalanced equation, the products of the reaction was not given, however, if one molecule of hydrogen and oxygen combine, hydrogen chloride (HCl) should be produced as the product of the reaction as in:
H2(g) + Cl2(9) ► 2HCl(g)
Kr 5s2 is the correct noble gas configuration for strontium
Answer:

Explanation:
1. Mass of acetylsalicylic acid (ASA)

2. Moles of ASA
HC₉H₇O₄ =180.16 g/mol

3. Concentration of ASA

4. Set up an ICE table

5. Solve for x
![K_{\text{a}} = \dfrac{\text{[H}_{3}\text{O}^{+}]\text{A}^{-}]} {\text{[HA]}} = 3.33 \times 10^{-4}\\\\\dfrac{x^{2}}{0.01757 - x} = 3.33 \times 10^{-4}\\\\\textbf{Check that }\mathbf{x \ll 0.01757}\\\\\dfrac{ 0.01757 }{3.33 \times 10^{-4}} = 53 < 400\\\\\text{The ratio is less than 400. We must solve a quadratic equation.}\\\\x^{2} = 3.33 \times 10^{-4}(0.01757 - x) \\\\x^{2} = 5.851 \times 10^{-6} - 3.33 \times 10^{-4}x\\\\x^{2} + 3.33 \times 10^{-4}x - 5.851 \times 10^{-6} = 0](https://tex.z-dn.net/?f=K_%7B%5Ctext%7Ba%7D%7D%20%3D%20%5Cdfrac%7B%5Ctext%7B%5BH%7D_%7B3%7D%5Ctext%7BO%7D%5E%7B%2B%7D%5D%5Ctext%7BA%7D%5E%7B-%7D%5D%7D%20%7B%5Ctext%7B%5BHA%5D%7D%7D%20%3D%203.33%20%5Ctimes%2010%5E%7B-4%7D%5C%5C%5C%5C%5Cdfrac%7Bx%5E%7B2%7D%7D%7B0.01757%20-%20x%7D%20%3D%203.33%20%5Ctimes%2010%5E%7B-4%7D%5C%5C%5C%5C%5Ctextbf%7BCheck%20that%20%7D%5Cmathbf%7Bx%20%5Cll%200.01757%7D%5C%5C%5C%5C%5Cdfrac%7B%200.01757%20%7D%7B3.33%20%5Ctimes%2010%5E%7B-4%7D%7D%20%3D%2053%20%3C%20400%5C%5C%5C%5C%5Ctext%7BThe%20ratio%20is%20less%20than%20400.%20We%20must%20solve%20a%20quadratic%20equation.%7D%5C%5C%5C%5Cx%5E%7B2%7D%20%3D%203.33%20%5Ctimes%2010%5E%7B-4%7D%280.01757%20-%20x%29%20%5C%5C%5C%5Cx%5E%7B2%7D%20%3D%205.851%20%5Ctimes%2010%5E%7B-6%7D%20-%203.33%20%5Ctimes%2010%5E%7B-4%7Dx%5C%5C%5C%5Cx%5E%7B2%7D%20%2B%203.33%20%5Ctimes%2010%5E%7B-4%7Dx%20-%205.851%20%5Ctimes%2010%5E%7B-6%7D%20%3D%200)
6. Solve the quadratic equation.


7. Calculate the pH
![\rm [H_{3}O^{+}]= x \, mol \cdot L^{-1} = 0.002258 \, mol \cdot L^{-1}\\\text{pH} = -\log{\rm[H_{3}O^{+}]} = -\log{0.002258} = \mathbf{2.65}\\\text{The pH of the solution is } \boxed{\textbf{2.65}}](https://tex.z-dn.net/?f=%5Crm%20%5BH_%7B3%7DO%5E%7B%2B%7D%5D%3D%20x%20%5C%2C%20mol%20%5Ccdot%20L%5E%7B-1%7D%20%3D%200.002258%20%5C%2C%20mol%20%5Ccdot%20L%5E%7B-1%7D%5C%5C%5Ctext%7BpH%7D%20%3D%20-%5Clog%7B%5Crm%5BH_%7B3%7DO%5E%7B%2B%7D%5D%7D%20%3D%20-%5Clog%7B0.002258%7D%20%3D%20%5Cmathbf%7B2.65%7D%5C%5C%5Ctext%7BThe%20pH%20of%20the%20solution%20is%20%7D%20%5Cboxed%7B%5Ctextbf%7B2.65%7D%7D)