All categories

3 years ago

You have a sample that has a h3o+ concentration of 1.25 x 10-5 m. what would be the [oh-]?

Chemistry

1 answer:

deff fn [24]3 years ago

7 0

Answer:

[OH⁻] = 8x10⁻¹⁰

Explanation:

Kw = 1x10⁻¹⁴

Kw = [H₃O⁺] . [OH⁻]

1x10⁻¹⁴ = 1.25x10⁻⁵ . [OH⁻]

1x10⁻¹⁴ / 1.25x10⁻⁵ = [OH⁻]

[OH⁻] = 8x10⁻¹⁰

You might be interested in

In a reaction 4 NH3 + 5 O2 → 4 NO + 6 H2O, 1 mole of ammonia reacts with 2 moles of oxygen. Which of these is correct after the

Vsevolod [243]

Answer:

Option B) All the ammonia is consumed

Explanation:

1. Balanced chemical equation (given):

$4NH_3+5O_2\rightarrow 4NO+6H_2O$

2. Theoretical mole ratios:

$4molNH_3:5molO_2:4molNO:6H_2O$

3. Limiting reactant:

When 1 mole of ammonia is combined with 2 moles of oxygen, the mole ratio is:

$1molNH_3:2molO_2$

Hence, one of the reactants will be completely consumed (the limiting reactant) and, after completion, an excess of the other will remain unreacted.

You need to compare the the actual ratio with the theoretical ratio.

4/5 > 1/2

Hence, NH₃ is in less proportion with respect to oxygen than what is theoretically needed, and the former is the limiting reactant.

Therefore, the 1 mole (all) of ammonia will be consumed, while some oxygen will remain as excess. This is described by the option B) All the ammonia is consumed.

4. Analyze the other options:

The amount of oxygen that will react is:

$1molNH_3\times5molO_2/4molNH3=5/4molO_2$

And the amount that will remain is:

$2molO_2-4/5molO_2=6/5molO_2$

Neither option A) nor C) describe that situation.

The amount of water produced is:

$1molNH_3\times 6molH_2O/4molNH_3=1.5molH_2O$ , which is not described by the option D).

Hence, the correct answer is the option B) All the ammonia is consumed.

6 0

3 years ago

How many moles are in 68.5g of KOH?

Dafna11 [192]

Answer: It has to be 56.10564

Explanation:1 grams KOH to mol = 0.01782 mol

10 grams KOH to mol = 0.17824 mol

20 grams KOH to mol = 0.35647 mol

30 grams KOH to mol = 0.53471 mol

40 grams KOH to mol = 0.71294 mol

50 grams KOH to mol = 0.89118 mol

100 grams KOH to mol = 1.78235 mol

200 grams KOH to mol = 3.5647

8 0

3 years ago

Read 2 more answers

select which of the following correctly represents the BALANCED chemical reaction for the production of HCL gas from its element

bagirrra123 [75]

Answer:

Choices 2 and 4

Explanation:

HCL is formed witthe the elements Hydrogen and Chlorine. Whatever is on the left side of the equation must match up with the right side of the equation.

2. H + Cl --> HCl (we have one hydrogen and one chlorine)

4. 2HCl --> H2 + Cl2 (since the two is distributed to both the H and the Cl, H has 2 and Cl has two on the left side AND on the right side of the equation)

3 0

2 years ago

What is the half-life (in seconds) of a zero-order reaction which has an initial reactant concentration of 0.884 M with a k valu

pantera1 [17]

Answer: 8.15s


Explanation:


1) A first order reaction is that whose rate is proportional to the concenration of the reactant:


r = k [N]


r = - d[N]/dt =


=> -d[N]/dt = k [N]


2) When you integrate you get:


N - No = - kt


3) Half life => N = No / 2, t = t'


=> No - No/ 2 = kt' => No /2 = kt' => t' = (No/2) / k


3) Plug in the data given: No = 0.884M, and k = 5.42x10⁻²M/s


t' = (0.884M/2) / (5.42x10⁻²M/s) = 8.15s

6 0

3 years ago

Read 2 more answers

Consider an oxygen-concentration cell consisting of two zinc electrodes. One is immersed in a water solution with a low oxygen c

blsea [12.9K]

Answer:

(a) The anode electrode which comprises the zinc electrode being placed in a water solution with low oxygen concentration.

(b) Cathodic reaction is: $O_{2} + 2H_{2}O + 4e^{-}$ ⇒ $4OH^{-}$

Anodic reaction is: $Zn$ ⇒ $Zn^{2+} + 2e^{-}$

Explanation:

In the given problem, we have an oxygen-concentration cell consisting of two zinc electrodes. One is immersed in a water solution with a low oxygen concentration and the other in a water solution with a high oxygen concentration. The zinc electrodes are connected by an external copper wire.

(a) Which electrode will corrode?

The electrode that will corrode is the anode electrode which comprises the zinc electrode being placed in a water solution with low oxygen concentration.

(b) Write half-cell reactions for the anodic reaction and the cathodic reaction.

Cathodic reaction is: $O_{2} + 2H_{2}O + 4e^{-}$ ⇒ $4OH^{-}$

Anodic reaction is: $Zn$ ⇒ $Zn^{2+} + 2e^{-}$

6 0

4 years ago