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3 years ago

Which of the following is not a characteristic of electromagnetic light waves?

Chemistry

2 answers:

scoray [572]3 years ago

6 0

Answer: Please help

A)They travel at the same speed through any one material.

B) They can be reflected and refracted.

C) They can't travel through a vacuum.

D) They obey the formula: velocity = wavelength × frequency

Lady bird [3.3K]3 years ago

3 0

Answer:

They can travel at various speeds through any one material. is not a characteristic of electromagnetic waves.

Explanation:

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A chemist designs a galvanic cell that uses these two half-reactions:

Nonamiya [84]

Answer :

(a) Reaction at anode (oxidation) : $4Fe^{2+}\rightarrow 4Fe^{3+}+4e^-$

(b) Reaction at cathode (reduction) : $O_2+4H^++4e^-\rightarrow 2H_2O$

(c) $O_2+4H^++4Fe^{2+}\rightarrow 2H_2O+4Fe^{3+}$

(d) Yes, we have have enough information to calculate the cell voltage under standard conditions.

Explanation :

The half reaction will be:

Reaction at anode (oxidation) : $Fe^{2+}\rightarrow Fe^{3+}+e^-$ $E^0_{anode}=+0.771V$

Reaction at cathode (reduction) : $O_2+4H^++4e^-\rightarrow 2H_2O$ $E^0_{cathode}=+1.23V$

To balance the electrons we are multiplying oxidation reaction by 4 and then adding both the reaction, we get:

Part (a):

Reaction at anode (oxidation) : $4Fe^{2+}\rightarrow 4Fe^{3+}+4e^-$ $E^0_{anode}=+0.771V$

Part (b):

Reaction at cathode (reduction) : $O_2+4H^++4e^-\rightarrow 2H_2O$ $E^0_{cathode}=+1.23V$

Part (c):

The balanced cell reaction will be,

$O_2+4H^++4Fe^{2+}\rightarrow 2H_2O+4Fe^{3+}$

Part (d):

Now we have to calculate the standard electrode potential of the cell.

$E^o=E^o_{cathode}-E^o_{anode}$

$E^o=(1.23V)-(0.771V)=+0.459V$

For a reaction to be spontaneous, the standard electrode potential must be positive.

So, we have have enough information to calculate the cell voltage under standard conditions.

4 0

3 years ago

Which of the following is a pure substance?<br>Air<br>Blood<br>Copper<br>Wood

krek1111 [17]

Answer:

copper

Explanation:

its an element, its not mixed with anything else

4 0

3 years ago

Read 2 more answers

Are the following quantum number combinations allowed? If not, show two ways to correct them:

evablogger [386]

Answer:

(a) n = 2; l = 0; ml = -1 ⇒ WRONG

change ml = 0, or l = 1 to correct.

(b) n = 4, l = 3; ml = -1 ⇒ CORRECT

(d) n = 5, l = 2; ml = +3 ⇒ WRONG

change ml = 0, ±1 or ±2, or l = 3 or l = 4 to correct.

Explanation:

The rules for electron quantum numbers are:

1. Shell number, 1 ≤ n

2. Subshell number, 0 ≤ l ≤ n − 1

3. Orbital energy shift, -l ≤ ml ≤ l

4. Spin, either -1/2 or +1/2

Now, apply in our case

(a) n = 2; l = 0; ml = -1 ⇒ WRONG

-l ≤ ml ≤ l, so either change ml = 0 or l = 1 to correct.

(b) n = 4, l = 3; ml = -1 ⇒ CORRECT

(d) n = 5, l = 2; ml = +3 ⇒ WRONG

-l ≤ ml ≤ l, so either change ml = 0, ±1 or ±2, or l = 3 or l = 4 to correct.

7 0

3 years ago

The compound chloral hydrate, known in detective stories as knockout drops, is composed of 14.52% C, 1.83% H, 64.30% Cl, and 19.

maria [59]

Answer:

C₂H₃Cl₃O₂

Explanation:

Given parameters:

Percentage composition:

14.52% C

1.83% H

64.30% Cl

19.35% O

Molar mass = 165.4 g/mo

Unknown:

Empirical formula = ?

Solution:

The empirical formula of a compound is the simplest formula of a compound. To solve this problem, let us follow the process below:

C H Cl O

%composition 14.52 1.83 64.3 19.35

Molar mass 12 1 17 16

number of

moles 14.52/12 1.83/1 64.3/3.5 19.35/16

1.21 1.83 1.81 1.21

Divide by

the smallest 1.21/1.21 1.83/1.21 1.81/1.21 1.21/1.21

1 1.51 1.51 1

multiply

by 2 2 3 3 2

Empirical formula C₂H₃Cl₃O₂

5 0

3 years ago

2H2 + O2 --> 2H2OHow many moles of hydrogen gas are needed to produce 120g of water?

wlad13 [49]

<h2>Answer:</h2>

6.67moles

<h2>Explanations:</h2>

Given the balanced chemical reaction between hydrogen and oxygen expressed as:

$2H_2+O_2\rightarrow2H_2O$

First, you need to calculate the moles of water produced.

$\begin{gathered} \text{Moles}=\frac{Mass}{\text{Molar mass}} \\ \text{Moles of water=}\frac{120}{2(1)+16} \\ \text{Moles of water}=\frac{120}{18} \\ \text{Moles of water}=6.67\text{moles} \end{gathered}$

Based on stochiometry, 2 moles of hydrogen produces 2 moles of water, hence the moles of hydrogen that will be needed to produce 120g of water is 6.67moles

6 0

1 year ago