True or False. Electromagnetic waves travel fastest through a vacuum. Question 2 options: True False

The reaction for the formation of phosgene from carbon monoxide and chlorineCO + Cl2 --> COCl2 is first order in CO and secon

Ilya [14]

Answer:

$r = k . [CO] .[Cl_{2}]$

Explanation:

Let´s consider the following reaction:

CO + Cl₂ ⇒ COCl₂

The general rate law is:

$r = k . [CO]^{m}. [Cl_{2}]^{n}$

where,

r is the rate of the reaction

k is the rate constant

[CO] and [Cl₂] are the molar concentrations of each reactant

m and n are the reaction orders for each reactant

Since the reaction is first order in CO, m = 1. The overall order is the sum of all the individual orders. In this case, the overall order m + n = 2. Then,

m + n = 2

n = 2 - m = 2 - 1 = 1

The reaction is first order in Cl₂.

The rate law is:

$r = k . [CO]. [Cl_{2}]$

6 0

4 years ago

What are words to decribe compact bones?

GrogVix [38]

Answer:

Compact bone, also called cortical bone, dense bone in which the bony matrix is solidly filled with organic ground substance and inorganic salts, leaving only tiny spaces (lacunae) that contain the osteocytes, or bone cells

Explanation:

4 0

4 years ago

The overall reaction and equilibrium constant value for a hydrogen-oxygen fuel cell at 298 K is given below. 2 H2(g) + O2(g) → 2

DENIUS [597]

Answer:

(a) ΔG° = -474 kJ/mol; E° = 1.23 V

(b) ΔH° negative; ΔS° negative

(c) Since ΔS is negative, as T increases, ΔG becomes more positive. Therefore, the maximum work obtained will decrease as T increases.

Explanation:

Let's consider the following reaction.

2 H₂(g) + O₂(g) → 2 H₂O(l)

with an equilibrium constant K = 1.34 × 10⁸³

(a) Calculate E° and ΔG° at 298 K for the fuel-cell reaction.

We can calculate the standard Gibbs free energy (ΔG°) using the following expression:

ΔG° = - R × T × lnK

ΔG° = - 8.314 × 10⁻³ kJ . mol⁻¹.K⁻¹ × 298 K × ln 1.34 × 10⁸³ = -474 kJ/mol

To calculate the standard cell potential (E°) we need to write oxidation and reduction half-reactions.

Oxidation: 2 H₂ ⇒ 4 H⁺ + 4 e⁻

Reduction: O₂ + 4 e⁻ ⇒ 2 O²⁻

The moles of electrons (n) involved are 4.

We can calculate E° using the following expression:

$E\°=\frac{0.0591V}{n} .logK\\E\°=\frac{0.0591V}{4} .log1.34 \times 10^{83}=1.23V$

(b) Predict the signs of ΔH° and ΔS° for the fuel-cell reaction. ΔH°: positive negative ΔS°: positive negative

The standard Gibbs free energy is related to the standard enthalpy (ΔH°) and standard entropy (ΔS°) through the following expression:

ΔG° = ΔH° - T.ΔS°

Usually, the major contribution to ΔG° is ΔH°. So, if ΔG° is negative (exergonic), ΔH° is expected to be negative (exothermic).

The entropy is related to the number of moles of gases. There are 3 gaseous moles in the reactants and 0 in the products, so the final state is predicted to be more ordered than the initial state, resulting in a negative ΔS°.

(c) As temperature increases, does the maximum amount of work obtained from the fuel-cell reaction increase, decrease, or remain the same?

The maximum amount of work obtained depends on the standard Gibbs free energy.

wmax = ΔG° = ΔH° - T.ΔS°

Since ΔS is negative, as T increases, ΔG becomes more positive. Therefore, the maximum work obtained will decrease as T increases.

5 0

4 years ago

Helpp! is Au an element, compound, or mixture?

Stels [109]

Answer:

It's an element.

Explanation:

Au is gold. An "element " on the periodic table. Trust me. Im 100% sure.

7 0

3 years ago

Read 2 more answers

Selah is making a mobile of an atom of beryllium to hang from the ceiling in her science class. She uses a clear plastic bag for

mel-nik [20]

Answer:

See explanation

Explanation:

The question is incomplete because the images of the models are absent. However, i will try to give you a general description of what the correct answer should be.

Beryllium is a member of group 2 in the periodic table. Beryllium has an atomic number of 4. This implies that it has four protons in its nucleus and four electrons in its shells. In a neutral atom, the number of electrons on the shells is equal to the number of protons in the nucleus.

The electronic configuration of Beryllium is 1s2 2s2. This implies that it should have two shells each containing only two electrons each.

Since we are using white foam balls for protons and black foam balls for neutrons, the clear plastic will contain four white foam balls and five black foam balls since the mass number of beryllium is 9 and number of neutrons = mass number - number of protons.

Four blue foam balls hanging from strings will represent the electrons around the nucleus.

Any model that corresponds to the description above is the correct answer.

7 0

3 years ago