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1. given ph = 8.55
find: [h3o+] and [oh-]
is this acidic, basic or neutral?
2. given ph = 3.50
find: [h3o+] and [oh-]
is this acidic, basic or neutral?
3. given [h3o+] = 3.67 x 10-8m
find: [oh-] and ph
is this acidic, basic or neutral?
4. given [h3o+] = 9.89 x 10-3m
find: [oh-] and ph
is this acidic, basic or neutral?
5. given [oh-] = 5.5 x 10-10m
find: [h3o+] and ph
is this acidic, basic or neutral?
6. given [oh-] = 8.5 x 10-2m
find: [h3o+] and ph
is this acidic, basic or neutral?
7. given [oh-] = 3.75 x 10-5m
is this acidic, basic or neutral?
how do you know?
8. given [h3o+] = 3.75 x 10-3m
is this acidic, basic or neutral?
how do you know?
9. given ph = 6.75,
is this acidic, basic or neutral?
how do you know?
10. given [h3o+] = 1.00 x 10-7m
is this acidic, basic or neutral?
how do you know?

1. [H₃O⁺] = 2.0 x 10⁻⁹ M.

   [OH⁻] = 3.55 x 10⁻⁶ M.

  The solution is basic.

2. [H₃O⁺] = 3.16 x 10⁻⁴ M.

   [OH⁻] = 3.16 x 10⁻¹¹  M.

  The solution is acidic.

3. [OH⁻] = 2.72 x 10⁻⁷ M.

   pH = 7.435.

   The solution is basic.

4. [OH⁻] = 9.89 x 10⁻³ M.

   pH = 2.0.

   The solution is acidic.

5. [H₃O⁺] = 1.82 x 10⁻⁵ M.

   pH = 4.74.

  The solution is acidic.

6.

[H₃O⁺] = 1.176 x 10⁻¹³ M.

   pH = 12.93.

   The solution is basic.

7. The solution is basic.

8. The solution is acidic.

9. The solution is acidic.

10. The solution is neutral.

Explanation:

pH = - log[H⁺],

pOH = - log[OH⁻],

Kw = [H⁺][OH⁻] = 10⁻¹⁴.

pH scale is a scale from 0 to 14, from which we can determine the nature of the solution:

1. Given pH = 8.55, Find: [H₃O⁺] and [OH⁻], Is this acidic, basic or neutral?

∵ pH = - log[H₃O⁺]

∴ 8.55 =  - log[H₃O⁺]

∴ [H₃O⁺] = 2.0 x 10⁻⁹ M.

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(2.0 x 10⁻⁹ M) = 3.55 x 10⁻⁶ M.

∵ pH = 8.55 > 7,

∴ The solution is basic.

2. Given pH = 3.50, Find: [H₃O⁺] and [OH⁻], Is this acidic, basic or neutral?

∵ pH = - log[H₃O⁺]

∴ 3.50 =  - log[H₃O⁺]

∴ [H₃O⁺] = 3.16 x 10⁻⁴ M.

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(3.16 x 10⁻¹⁴ M) = 3.16 x 10⁻¹¹ M.

∵ pH = 3.50 < 7,

∴ The solution is acidic.

3. Given [H₃O⁺] = 3.67 x 10⁻⁸ M, Find: [OH⁻] and pH, Is this acidic, basic or neutral?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(3.67 x 10⁻⁸ M) = 2.72 x 10⁻⁷ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(3.67 x 10⁻⁸ M) = 7.435.

∵ pH = 7.435 > 7,

∴ The solution is basic.

4. Given [H₃O⁺] = 9.89 x 10⁻³ M, Find: [OH⁻] and pH, Is this acidic, basic or neutral?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(9.89 x 10⁻³ M) = 9.89 x 10⁻³ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(9.89 x 10⁻³ M) = 2.0.

∵ pH = 2.0 < 7,

∴ The solution is acidic.

5. Given [OH⁻] = 5.5 x 10⁻¹⁰ M, Find: [H₃O⁺] and pH, Is this acidic, basic or neutral?

 ∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(5.5 x 10⁻¹⁰ M) = 1.82 x 10⁻⁵ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.82 x 10⁻⁵ M) = 4.74.

∵ pH = 4.74 < 7,

∴ The solution is acidic.

6. Given [OH⁻] = 8.5 x 10⁻² M, Find: [H₃O⁺] and pH, Is this acidic, basic or neutral?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(8.5 x 10⁻² M) = 1.176 x 10⁻¹³ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.176 x 10⁻¹³ M) = 12.93.

∵ pH = 12.93 > 7,

∴ The solution is basic.

7. Given [OH⁻] = 3.75 x 10⁻⁵ M, Is this acidic, basic or neutral?  How do you know?

∵ Kw = [H₃O⁺][OH⁻] = 10⁻¹⁴.

∴  [H₃O⁺] = 10⁻¹⁴/[OH⁻] = 10⁻¹⁴/(3.75 x 10⁻⁵ M) = 2.67 x 10⁻¹⁰ M.

∵ pH = - log[H₃O⁺]

∴ pH = - log(2.67 x 10⁻¹⁰ M) = 9.57.

∵ pH = 9.57 > 7,

∴ The solution is basic.

8. Given [H₃O⁺] = 3.75 x 10⁻³ M, Is this acidic, basic or neutral?  How do you know?

∵ pH = - log[H₃O⁺]

∴ pH = - log(3.75 x 10⁻³ M) = 2.43.

∵ pH = 2.43 < 7,

∴ The solution is acidic.

9. Given pH = 6.75,  Is this acidic, basic or neutral?  How do you know?

∵ pH = 6.75 < 7,

∴ The solution is acidic.

10. Given [H₃O⁺] = 1.00 x 10⁻⁷ M, Is this acidic, basic or neutral?  How do you know?

∵ pH = - log[H₃O⁺]

∴ pH = - log(1.0 x 10⁻⁷ M) = 7.0.

∵ pH = 7.0,

∴ The solution is neutral.

gravity causes stares to cluster i think so

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"