Which of these is a form of potential energy

Which equation represents single replacement reaction? A) CH4 + 2 02 → CO2 + 2 H2O B) CaCO3 + CaO + CO2 C) 2 Na + 2 H2O → 2 NaOH

loris [4]

Answer:

C) 2 Na + 2 H2O → 2 NaOH + H2.

Explanation:

Hello there!

In this case, according to the given chemical reactions, it is possible to firstly understand that a single displacement reaction is characterized by the presence of a single element as the first reactant and a compound as the second one, thus, yielding a compound as the first product and a single element as the second one.

In such a way, according to the given choices, it possible to note that C) 2 Na + 2 H2O → 2 NaOH + H2 is the only one with the aforementioned condition as the element at the reactants side is Na and at the products side is H2.

Best regards!

6 0

2 years ago

Ca(OH)2 (s) precipitates when a 1.0 g sample of CaC2(s) is added to 1.0 L of distilled water at room temperature. If a 0.064 g s

Nina [5.8K]

Answer:

D) Ca(OH)₂ will not precipitate because Q < Ksp

Explanation:

Here we have first a chemical reaction in which Ca(OH)₂ is produced:

CaC₂(s) + H₂O ⇒ Ca(OH)₂ + C₂H₂

Ca(OH)₂ is slightly soluble, and depending on its concentration it may precipitate out of solution.

The solubility product constant for Ca(OH)₂ is:

Ca(OH)₂(s) ⇆ Ca²⁺(aq) + 2OH⁻(aq)

Ksp = [Ca²⁺][OH⁻]²

and the reaction quotient Q:

Q = [Ca²⁺][OH⁻]²

So by comparing Q with Ksp we will be able to determine if a precipitate will form.

From the stoichiometry of the reaction we know the number of moles of hydroxide produced, and since the volume is 1 L the molarity will also be known.

mol Ca(OH)₂ = mol CaC₂( reacted = 0.064 g / 64 g/mol = 0.001 mol Ca(OH)₂

the concentration of ions will be:

[Ca²⁺ ] = 0.001 mol / L 0.001 M

[OH⁻] = 2 x 0.001 M = 0.002 M ( From the coefficient 2 in the equilibrium)

Now we can calculate the reaction quotient.

Q= [Ca²⁺][OH⁻]² = 0.001 x (0.002)² = 4.0 x 10⁻⁹

Q < Ksp since 4.0 x 10⁻⁹ < 8.0 x 10⁻⁸

Therefore no precipitate will form.

The answer that matches is option D

8 0

3 years ago

you are given a solution of lead nitrate. use any of the solution used in this experiment to form a white precipitate of lead ch

Vesnalui [34]

We have as a reagent a salt, lead nitrate (Pb(NO3)2), and an unknown solution that gives us as a product lead chloride (PbCl2). That is, the solution must contain chlorine.

If a chlorine solution is used we will have the following reaction:

$Pb(NO_{3)2}+2Cl^-\rightarrow PbCl_2+2NO^-_3$

So, with a chlorine solution, we will have a white precipitate of lead chloride.

7 0

1 year ago

When aqueous ammonia is added to a solution containing Bi3+ and Cu2+ cations, ____________ occurs. A. Reduction to black bismuth

MissTica

Answer:

C. Precipitation of white bismuth hydroxide.

Explanation:

When aqueous ammonia is added to a solution that has Bi3+ and CU2+ cations, what we would have as a chemical result is the precipitation of white Bismuth hydroxide.

The chemical reaction for this can be written as,

Bi3+ + 2NH3 + 3H2O ⇌ Bi(OH)3(s) + 3NH4

Thank you!

6 0

2 years ago

Select the correct answer. Which is true according to the law of conservation of energy? A. In a closed system, the total amount

mojhsa [17]

in the image there is answer okk

8 0

2 years ago