1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Norma-Jean [14]
3 years ago
7

Which is least likely to be reduced? A. Zn^2+ B. Fe^3+ C. Cu^2+ D. Fe^2+

Chemistry
1 answer:
alekssr [168]3 years ago
6 0

A. Zn²⁺

<h3>Further explanation</h3>

Given

Cations of several elements

Required

The least to be reduced

Solution

If we look at the voltaic series:

<em>Li-K-Ba-Ca-Na-Mg-Al-Mn- (H2O) -Zn-Cr-Fe²⁺-Cd-Co-Ni-Sn-Pb- (H) -Cu-Hg-Fe³⁺-Ag-Pt-Au </em>

The electrode which is easier to reduce than the hydrogen (H2) electrode has a positive sign (E red= +) and is located to the right of the voltaic series (right of H)

The electrode which is easier to oxidize than the hydrogen (H2) electrode and is difficult to experience reduction has a negative sign (E red= -) and is located to the left of the voltaic series (left of H)

Or you can look at the standard reduction potential value of the metals in the answer options, and the most negative reduction E° value which will be difficult to reduce.

The Zn metal is located far left of the other metals in the answer choices, so it is the most difficult to reduce

You might be interested in
Please Help!!!
STatiana [176]

Answer:

single replacement

Explanation:

Step 1: Data given

single replacement = A reaction in which one element replaces a similar element in a compound. For example, a metal replaces an other metal.

The general form of a single-replacement (also called single-displacement) reaction is:

A+BC→AC+B

Decomposition = a reaction in which a compound breaks down into two or more simpler substances. The general form of a decomposition reaction is:

AB→A+B

Synthesis =  A reaction that occurs when one or more compounds combines to form a complex compound:

A + B → AB

Double replacement: a reaction in which the positive and negative ions of two ionic compounds exchange places to form two new compounds.

The general form of a double-replacement reaction is:

AB+CD→AD+BC

Combustion reaction = a reaction in which a substance reacts with oxygen gas, releasing energy in the form of light and heat. Combustion reactions must involve  O2  as one reactant.

The reaction Zn + 2HCl → ZnCl2 + H2

⇒ Does not involve O2 = NOT a combustion reaction

⇒ The compounds do not form a complex compound = NOT a synthesis

⇒ A compound does not break down into smaller substances = NOT a decomposition

⇒ There is a replacement between Zn and H. This is a <u>single replacement</u>, not a double replacement reaction.

6 0
3 years ago
determine the ph of a buffer that is 0.55 M HNO2 and 0.75 M KNO2. tha value of Ka for HNO2 is 6.8*10^-4
Mariana [72]

Answer:

pH = 3.3

Explanation:

Buffer solutions minimize changes in pH when quantities of acid or base are added into the mix. The typical buffer composition is a weak electrolyte (wk acid or weak base) plus the salt of the weak electrolyte. On addition of acid or base to the buffer solution, the solution chemistry functions to remove the acid or base by reacting with the components of the buffer to shift the equilibrium of the weak electrolyte left or right to remove the excess hydronium ions or hydroxide ions is a way that results in very little change in pH of the system. One should note that buffer solutions do not prevent changes in pH but minimize changes in pH. If enough acid or base is added the buffer chemistry can be destroyed.

In this problem, the weak electrolyte is HNO₂(aq) and the salt is KNO₂(aq). In equation, the buffer solution is 0.55M HNO₂ ⇄ H⁺ + 0.75M KNO₂⁻ . The potassium ion is a spectator ion and does not enter into determination of the pH of the solution. The object is to determine the hydronium ion concentration (H⁺) and apply to the expression pH = -log[H⁺].

Solution using the I.C.E. table:

              HNO₂ ⇄    H⁺   +   KNO₂⁻

C(i)        0.55M       0M      0.75M

ΔC            -x            +x          +x

C(eq)  0.55M - x       x     0.75M + x    b/c [HNO₂] / Ka > 100, the x can be                                    

                                                             dropped giving ...

           ≅0.55M        x       ≅0.75M        

Ka = [H⁺][NO₂⁻]/[HNO₂] => [H⁺] = Ka · [HNO₂]/[NO₂⁻]

=> [H⁺] = 6.80x010⁻⁴(0.55) / (0.75) = 4.99 x 10⁻⁴M

pH = -log[H⁺] = -log(4.99 x 10⁻⁴) -(-3.3) = 3.3

Solution using the Henderson-Hasselbalch Equation:

pH = pKa + log[Base]/[Acid] = -log(Ka) + log[Base]/[Acid]

= -log(6.8 x 10⁻⁴) + log[(0.75M)/(0.55M)]

= -(-3.17) + 0.14 = 3.17 + 0.14 = 3.31 ≅ 3.3

3 0
3 years ago
The graph given below shows the motion of four runners P, Q, R, and S in a 5 km marathon.
wel

Answer:-

As we can see from the graphical data,

The distance covered by all the four runners is the same 5 km.

Among the four athletes, Athlete P covers the distance in under three hours.

It is the minimum time taken among the four athletes.

Thus Athlete P covers the 5 km distance in the minimum amount of time.

We know that speed = \frac{Distance}{Time}

Since time taken for P is minimum, his speed is the maximum. P ran the fastest.

Time taken by Q = 4.5 hours.

Speed of Q = \frac{Distance}{Time taken by Q}

                     = \frac{5km}{4.5hour}

                    = 1.1 km/ hr

Time taken by R = 6 hours.

Speed of R = \frac{Distance}{Time taken by R}

                     = \frac{5km}{6hour}

                    = 0.8 km/ hr

3 0
3 years ago
A teacher uses a bow and arrow to demonstrate accuracy and precision. She shoots several arrows, aiming at the exact center of t
RUDIKE [14]

Answer:Doing your momveryhardrn

Explanation:

She is visciously suckingmynuts

5 0
3 years ago
What are the steps to evaporation but without heat just evaporation steps to follow
densk [106]
First, the sun shines liquid (ocean) Next, the water evaporates 
8 0
3 years ago
Read 2 more answers
Other questions:
  • PLS help it is a timed test!
    6·1 answer
  • What contribution did these scientists make to atomic models of the atom?
    6·1 answer
  • How many moles of ethylene (C2H4) can react with 12.9 liters of oxygen gas at 1.2 atmospheres and 297 Kelvin? C2H4(g) + 3O2(g) y
    10·1 answer
  • Which statement describe acids
    5·1 answer
  • Which is an intermolecular force? select one:
    8·1 answer
  • What is its molecular compound name for CI4
    14·1 answer
  • If the volume of a substance is measured with a graduated cylinder, the unit of measure for volume will be:
    10·1 answer
  • Josefina and Raul were comparing how sound moves through various mediums and how charge moves through conducting wires. They per
    5·1 answer
  • You already know that some materials, such as olive oil, will not dissolve in water. In fact, oil will float on top of water. Ex
    13·1 answer
  • The combining power of an element is called ?
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!