Testbank, Question 098 In the reaction between an alkyne and Na metal in liquid ammonia, the role of Na is as a(n) ___________.a. catalyst
b. electrophile
c. Brønsted base
d. reducing agent
e. Bronsted acid

Answer:

ksp = 0,176

Explanation:

The borax (Na₂borate) in water is in equilibrium, thus:

Na₂borate(s) ⇄ borate²⁻(aq) + 2Na⁺(aq)

When you add just borax, the moles of Na²⁺ are twice the moles of borate²⁻, that means 2borate²⁻=Na⁺ (1)

The ksp is defined as:

ksp = [borate²⁻] [Na⁺]²

Then, borate²⁻(B₄O₇²⁻) reacts with HCl thus:

B₄O₇²⁻ + 2HCl + 5H₂O → 4H₃BO₃ + 2Cl⁻

The moles of HCl that reacts with B₄O₇²⁻ are:

0,500M×0,01200L = 6,00x10⁻³ mol of HCl

As two moles of HCl react with 1 mol of B₄O₇²⁻, the moles of B₄O₇²⁻ are:

6,00x10⁻³ mol of HCl× = 3,00x10⁻³ mol of B₄O₇²⁻

For (1), moles of Na⁺ are 3,00x10⁻³ mol ×2 = 6,00x10⁻³ mol of Na⁺

The [borate²⁻] is 3,00x10⁻³ mol of B₄O₇²⁻/0,00850L = 0,353M

And [Na⁺] is 6,00x10⁻³ mol of Na⁺ / 0,00850L = 0,706M

Replacing in the expression of ksp:

ksp = [0,353] [0,706]²

ksp = 0,176

I hope it helps!

Explanation:

Acids are the species which furnish protons (hydrogen ions) when dissolved in the water.

Bases are the species which furnish hydroxide ions when dissolved in the water.

Oxoacid is the acid which contains with at least one hydrogen atom which is  bonded to the oxygen atom in the molecule which can dissociate in the solution to give proton and the corresponding anion.

Oxoanion is the anion which is derived from oxoacid by the loss of hydrogen atom which is bounded to the oxygen.

A hydrate is the specie which contains water molecule or it's constituents in its solid structure.

Final answer:

The movement of the upper mantle and the tectonic plates of the Earth's lithosphere results in the movement of the Earth's crust. The tectonic plates float on the asthenosphere, a semi-fluid part of the upper mantle, and are driven by convection currents.

Explanation:

The movement of Earth's plates is driven by the upper mantle. The Earth's lithosphere, which is the topmost layer consisting of the crust and the rigid upper part of the mantle, is broken up into tectonic plates. These tectonic plates float on the semi-fluid layer of the mantle known as the asthenosphere. Convection currents in the asthenosphere, which is part of the upper mantle, move these plates. Thus, the upper mantle has a significant role in the movement of the Earth's crust.

Learn more about Movement of Earth's Plates here:

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Answer:

2Al(NO_{3} )_{3} + 3K_{2}SO_{4} ----> Al_{2}(SO_{4})_{3} + 6KNO_{3}

Explanation:

Answer:

3,8×10⁻⁵ mol/L of potassium permanganate solution

Explanation:

To calculate concentration in mol/L you must convert the 3,8 umol to moles and 100 mL to liters, knowing 1 umol are 1×10⁻⁶mol and 1L are 1000 mL.

3,8 umol × (1×10⁻⁶mol / 1 umol ) = 3,8×10⁻⁶mol of potassium permanganate.

100 mL × ( 1L / 1000 mL) = 0,100 L

Thus, concentration in mol/L is:

3,8×10⁻⁶mol / 0,100 L = 3,8×10⁻⁵ mol/L of potassium permanganate solution

I hope it helps!

Answer:

4 pairs are needed for the bonds, leaving 1 lone pair. Each double bond uses 2 bond pairs and can be thought of as a single unit. There are 2 double bond units and 1 lone pair, which will try to get as far apart as possible - taking up a trigonal planar arrangement.