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PtichkaEL [24]
3 years ago
13

What is the concentration of hydroxide ions in pure water at 30.0 ∘C, of Kw at this temperature is 1.47x10-14?

Chemistry
1 answer:
klio [65]3 years ago
7 0

Answer:

[OH⁻] = 1.21×10⁻⁷

Explanation:

Water dissociates in the solution as:

H₂O ⇔ H⁺ + OH⁻

For pure water, the concentration of [H⁺] and [OH⁻] are equal.

Kw is defined as the product of the active concentration of  H⁺ and OH⁻ furnished by the water.

So,

Kw = [H⁺] [OH⁻]

Given that, at 30.0 °C, the Kw is 1.47×10⁻¹⁴

So,

Kw = [H⁺] [OH⁻]

As stated above, [H⁺] = [OH⁻]

1.47×10⁻¹⁴ = [OH⁻]²

<u>[OH⁻] = 1.21×10⁻⁷</u>

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During a combustion reaction, 9.00 grams of oxygen reacted with 3.00 grams of CH4.
Monica [59]

Answer:

0.74 grams of methane

Explanation:

The balanced equation of the combustion reaction of methane with oxygen is:

  • CH₄ + 2 O₂ → CO₂ + 2 H₂O

it is clear that 1 mol of CH₄ reacts with 2 mol of O₂.

firstly, we need to calculate the number of moles of both

for CH₄:

number of moles = mass / molar mass = (3.00 g) /  (16.00 g/mol) = 0.1875 mol.

for O₂:

number of moles = mass / molar mass = (9.00 g) /  (32.00 g/mol) = 0.2812 mol.

  • it is clear that O₂ is the limiting reactant and methane will leftover.

using cross multiplication

1 mol of  CH₄ needs → 2 mol of O₂

???  mol of  CH₄  needs → 0.2812 mol of O₂

∴ the number of mol of CH₄ needed = (0.2812 * 1) / 2 = 0.1406 mol

so 0.14 mol will react and the remaining CH₄

mol of CH₄ left over = 0.1875 -0.1406 = 0.0469 mol

now we convert moles into grams

mass of CH₄ left over = no. of mol of CH₄ left over *  molar mass

                                    = 0.0469 mol * 16 g/mol = 0.7504 g

So, the right choice is 0.74 grams of methane

3 0
3 years ago
PLEASE HELP I BEG
Gwar [14]

Answer:

1.Velocity and pitch

2.The unit of vibration is hertz. The number of oscillations of an oscillating body per second is known as frequency. Complete step by step answer: The time taken by a vibrating body to complete one vibration is time period.

3.Frequencies above 20,000 Hz are known as ultrasound.

5 0
3 years ago
Hot air balloons work due to a current moving heat energy around within the balloon. which heat energy transfer process is happe
miv72 [106K]

Answer:

Convection.

Explanation:

Why? This transfer of heat energy away from the ground by the vertical movement of air is called "free convection" or "natural convection." A hot air balloon rises because warmer air is less dense than cool air.                                                (plz brainlyest)

3 0
3 years ago
Read 2 more answers
2CO + O2 → 2002
Reika [66]

Answer:

B: Increasing the volume inside the reaction chamber

Explanation:

5 0
3 years ago
Calculate the value of the equilibrium constant, Kc , for the equilibrium shown below, if 0.124 moles of NO, 0.0240 mole of H2,
sdas [7]

the reaction is

2NO(g) + 2H2(g) <—> N2(g) + 2H2O (g)

Kc = [N2] [ H2O]^2 / [NO]^2 [ H2]^2

Given

moles of NO = 0.124 therefore [NO] = moles /volume = 0.124 /2 = 0.062

moles of H2 = 0.0240 , therefore [H2] = moles / volume = 0.0240 / 2 = 0.012

moles of N2 = 0.0380 , therefore [N2] = moles / volume = 0.0380 / 2 = 0.019

moles of H2O  = 0.0276 , therefore [H2O] = moles / volume = 0.0276 / 2 = 0.0138

Kc = (0.019) ( 0.0138)^2 / (0.062)^2 ( 0.012)^2 = 6.54



4 0
3 years ago
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