helpp me please i need help ​

Answer:

0.3793 M

Explanation:

The unknown metal is zinc. So the equation of the reaction is;

Zn(s) + Cu^2+(aq) -------> Zn^2+(aq) + Cu(s)

From Nernst equation;

E = E° - 0.0592/n log Q

[Cu2+] = 0.050179 M

n = 2

[Zn^2+] = ?

E = 1.074 V

E° = 0.34 - (-0.76) = 1.1 V

Substituting values;

1.074  = 1.1 - 0.0592/2 log [Zn^2+]/0.050179

1.074 - 1.1 = - 0.0592/2 log [Zn^2+]/0.050179

-0.026 = -0.0296  log [Zn^2+]/0.050179

-0.026/-0.0296 = log [Zn^2+]/0.050179

0.8784 =log [Zn^2+]/0.050179

Antilog(0.8784) = [Zn^2+]/0.050179

7.558 =  [Zn^2+]/0.050179

[Zn^2+] = 7.558 * 0.050179

[Zn^2+] = 0.3793 M

Explanation:

silver is the best conductor

Answer:

Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely. Instead of orbiting their respective atoms, they form a sea of electrons that surround the positive nuclei of the interacting metal ions

Answer:I'm going to give some fictitious values just so that we can get some perspective on the matter.

Let's say that the surface temperature of our sun is 10, the surface temp of the bigger star- the red giant formed from leaving the main sequence, has a temp of 0.2. of that- 2.

We can also say that the radius of our sun is 10, and the radius of the red giant is 1000. (100 times more)

Using the equation:

L

=

σ

A

T

4

σ

= The Stefan-Boltzmann constant =

5.67

×

10

−

8

But we can ignore the constant, as we are only interested in a ratio of these values.

L

S

u

n

=

4

π

(

10

)

2

×

10

4

=

1.26

×

10

7

L

S

t

a

r

=

4

π

(

1000

)

2

×

2

4

≈

2.01

×

10

8

2.01

×

10

8

1.26

×

10

8

≈

16

So the newly formed, red giant star is almost 16 times more luminous than the sun. This is owing to the increased surface area of the star due to the massively increased radius.

A small sidenote:

There is an equation that might be useful for comparing the radii, temperature and luminosity of main sequence stars. As red giants are not on the main sequence it could not be used here, but if you stumble across a question where they ask you to find the radius, luminosity or temperature given the other two, you can relate it to the sun's characteristics:

r

s

t

a

r

r

s

u

n

=

√

L

s

t

a

r

L

s

u

n

×

(

T

s

u

n

T

s

t

a

r

)

2

(I know, it's not a beauty to look at- but it works)

Where

X

s

u

n

is the radius, temperature, and luminosity of the sun. These are not often given in numerical values, but this equation serves well when asked to find e.g the radius of a star, in solar radii given that a star is twice as luminous and has 5 times the temperature of that of the sun.

Hence:

T

s

t

a

r

=

5

T

s

u

n

L

s

t

a

r

=

2

L

s

u

n

r

s

t

a

r

r

s

u

n

=

√

2

L

s

u

n

L

s

u

n

×

(

T

s

u

n

5

T

s

u

n

)

2

(cancel the common terms)

r

s

t

a

r

r

s

u

n

=

√

2

×

(

1

5

)

2

r

s

t

a

r

≈

0.057

r

s

u

n

(divide both sides by 0.0057)

17.5

r

s

t

a

r

≈

r

s

u

n

So the star's radius is almost 17.5 times that of the sun.

Hopefully, you find this info useful!

Explanation:

Answer:

9th:08473 kJ/mol

Explanation:

HAHAHAHAHAHAHAHAHAHA

Answer:

487638640,7819

dndndnndndbxbdbdbdbdb

Answer:

true

Explanation:

you are getting closer to the core hope this helps!

Answer:

Explanation:

One farad of charge is capable of depositing one gram equivalent of a metal

One gram equivalent of Ag = 108 grams

One gram equivalent of Cd = 112 / 2  grams

= 56 grams . [ for cadmium equivalent mass = atomic mass / s ]

electric charge flowing = current x time = 5 x 600 = 3000 coulomb

one farad = 96500 coulomb

96500 coulomb  deposits 108 gram of Ag

3000 coulomb deposits 108 x 3000 / 96500 gram

= 3.35 grams of Ag

Similarly ,

96500 coulomb  deposits 56 gram of Cd

3000 coulomb deposits 56 x 3000 / 96500 gram

= 1.74  grams of Cd

So there will be much larger increase in the spoon of Ag due to larger deposit of Ag by charge .

2NH3 + 302---> 2NO + 3H20

Answer:

Mechanical Energy- Energy that result from movement or the location of the object. Is the sum of kinetic and potential energy.

Thermal Energy- Thermal energy or heat energy reflects the temperature difference between two systems.

Nuclear Energy-  is energy resulting from changes in the atomic nuclei or from nuclear reactions.

Chemical Energy- results from chemical reactions between atoms or molecules.

More:

Kinetic energy- is the energy of motion of a body. It ranges from 0 to a positive value.

Electromagnetic energy- (or radiant energy) is energy from light or electromagnetic waves.

Sonic energy-  is the energy of sound waves. Sound waves travel through the air or another medium.

Gravitational energy- energy associated with gravity involves the attraction between two objects based on their mass.

Ionization energy- is the form of energy that binds electrons to the nucleus of its atom, ion, or molecule.

Potential energy- is the energy of an object's position.

Explanation:

Hope this helps

Answer:

exothermic means that energy was released during the chemical reaction

Explanation:

Answer: 3

Explanation: A P E X

Answer:

Emulsion

Explanation:

Emulsion is a special type of mixture formed by combining two liquids that do not normally mix. An example of emulsion is;

Oil and Water

Answer:

adding

opposite

Explanation:

dont blame me if u get them wrong

Answer:

first one is adding i belive and second one is opposite

Explanation:

Answer:

[Ar] 3d¹⁰ 4s² 4p⁶

Explanation:

Krypton is a chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. With rare exceptions, krypton is chemically iner,

Answer:

Q = ΔH fusion * mass (g)

when we have:

ΔH fusion (the heat (or enthalpy) of fusion = 0.334 kJ/g

and mass of ice = 22.4 g  

so by substitution, we can get the energy (Q) required to melt this mass of ice:

∴ Q = 0.334KJ/g * 22.4 g  

      = 7.48 KJ

∴ the energy required to melt 22.4 g of ice is = 7.48 KJ

Explanation:

A per the statement the true and false have been stated.

Learn more about the statement is correct and False if it is incorrect.

brainly.com/question/25942470.

Answer:

1 - Weak electrolyte

2- Non electrolyte

3- Weak electrolyte

4- Strong electrolyte

Explanation:

A strong electrolyte refers to an electrolyte that decomposes completely in solution. This means that there are more charge carriers in solution when a strong electrolyte is dissolved in water. A strong electrolyte produces a strong glow. LiOH is a strong electrolyte.

A weak electrolyte is not completely dissociated in water. Only a small amount dissociates in water. HF is a weak electrolyte. A weak electrolyte does not produce a bright light.

A non-electrolyte does not dissociate in solution at all hence it does not power a bulb E.g  C12H22O11.

Answer:

7/16

Explanation:

The general formula for the combustion of alkanes is;

CnH2n+2 + 3n+1/2 O2  -------> nCO2 + (n+1)H2O

So, we have;

CnHn + nO2 ------> 7CO2 + 8H2O

So there are 7 carbon atoms and 16 hydrogen atoms in heptane according to the law of conservation of mass.

Therefore, heptane is; C7H16

The ratio of carbon to hydrogen is now; 7/16

Ce clasă ești sa văd daca te pot ajuta

Answer:

it gives base, it is process of neutralization,when acid reacts with base it gives salt and water

Answer:

3

Explanation:

1 Calcium atom and two chlorine atoms

The copper itself can react with hydrogen

Here is the chemical reaction

2CuCl2(aq) + H2(g) -> 2CuCl(s) + 2HCl(g)

Explanation:

momentum increases with an increase in mass and velocity

Answer:

12.084 lb

Explanation:

1 gram = 0.00220462 lb

multiply number of grams by 0.00220462

Ex. 2000 g x 0.00220462 = 4.409 pounds

Answer:

The law of multiple proportions states that whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.

Answer:

diiodo????

Explanation:

recheck the question and resend

Answer:

Explanation:

Solid ice floats over water because ice is less dense than liquid water, or weighs less, by about 10%, than liquid water

Answer:

It is electrical → heat, sound, and motion

because a hair dryer makes heat to dry your hair and sound is the blowing and motion is how it goes

Explanation:

Answer:

A

Explanation:

electrical -- heat sound, and motion

Answer:

A- pH = 13.12

B- pH = 12.91

C- pH = 12.71

D- pH = 12.43

E- pH = 11.55

F- pH = 7

G- pH = 2.46

H- pH = 1.88

Explanation:

This is a titration of a strong base with a strong acid. The neutralization reaction is: KOH (aq) + HCl (aq) →  H₂O(l) + KCl(aq)

Our pH at the equivalence point is 7, because we have made a neutral salt.

To determine the volume at that point we state the formula for titration:

mmoles of base = mmoles of acid

Volume of base  . M of base = Volume of acid . M of acid

50mL . 0.129M = 0.258 M . Volume of acid

Volume of acid = (50mL . 0.129M) / 0.258 M →  25 mL (Point F)

When we add 25 mL of HCl, our pH will be 7.

A- At 0 mL of acid, we only have base.

KOH → K⁺ + OH⁻

[OH⁻] = 0.129 M

To make more easy the operations we will use, mmol.

mol . 1000 = mmoles → mmoles / mL = M

- log 0.129 = 0.889

14 - 0.889 = 13.12

B-  In this case we are adding, (7 mL . 0.258M) = 1.81 mmoles of H⁺

Initially we have  0.129 M . 50 mL = 6.45 mmoles of OH⁻

1.81 mmoles of H⁺ will neutralize, the 6.45 mmoles of OH⁻ so:

6.45 mmol - 1.81 = 4.64 mmoles of OH⁻

This mmoles of OH⁻ are not at 50 mL anymore, because our volume has changed. (Now, we have 50 mL of base + 7 mL of acid) = 57 mL of total volume.

[OH⁻] = 4.64 mmoles / 57 mL = 0.0815 M

- log 0.0815 M = 1.09 → pOH

pH = 14 - pOH → 14 - 1.09 = 12.91

C- In this case we add (12.5 mL . 0.258M) = 3.22 mmoles of H⁺

Our initial mmoles of OH⁻ would not change through all the titration.

Then 6.45 mmoles of OH⁻ are neutralized by 3.22 mmoles of H⁺.

6.45 mmoles of OH⁻ - 3.22 mmoles of H⁺ = 3.23 mmoles of OH⁻

Total volume is: 50 mL of base + 12.5 mL = 62.5 mL

[OH⁻] = 3.23 mmol / 62.5 mL = 0.0517 M

- log  0.0517 = 1.29 → pOH

14 - 1.11 = 12.71

D- We add (18 mL . 0.258M) = 4.64 mmoles of H⁺

6.45 mmoles of OH⁻ are neutralized by 4.64 mmoles of H⁺.

6.45 mmoles of OH⁻ - 4.64 mmoles of H⁺ = 1.81 mmoles of OH⁻

Total volume is: 50 mL of base + 18 mL = 68 mL

[OH⁻] = 1.81 mmol / 68 mL = 0.0265 M

- log  0.0265 = 1.57 → pOH

14 - 1.57 = 12.43

E- We add (24 mL . 0.258M) = 6.19 mmoles of H⁺

6.45 mmoles of OH⁻ are neutralized by 6.19 mmoles of H⁺.

6.45 mmoles of OH⁻ - 6.19 mmoles of H⁺ = 0.26 mmoles of OH⁻

Total volume is: 50 mL of base + 24 mL = 74 mL

[OH⁻] = 0.26 mmol / 74 mL = 3.51×10⁻³ M

- log  3.51×10⁻³  = 2.45 → pOH

14 - 2.45 = 11.55

F- This the equivalence point.

mmoles of OH⁻ = mmoles of H⁺

We add (25 mL . 0.258M) = 6.45 mmoles of H⁺

All the OH⁻ are neutralized.

OH⁻  +  H⁺  ⇄   H₂O              Kw

[OH⁻] = √1×10⁻¹⁴   →  1×10⁻⁷  →  pOH = 7

pH → 14 - 7 = 7

G- In this case we have an excess of H⁻

We add (26 mL . 0.258M ) = 6.71 mmoles of H⁺

We neutralized all the OH⁻ but some H⁺ remain after the equilibrium

6.71 mmoles of H⁺ - 6.45 mmoles of OH⁻ = 0.26 mmoles of H⁺

[H⁺] = 0.26 mmol / Total volume

Total volume is: 50 mL + 26 mL → 76 mL

[H⁺] = 0.26 mmol / 76 mL → 3.42×10⁻³ M

- log 3.42×10⁻³ = 2.46 → pH

H- Now we add (29 mL . 0.258M) = 7.48 mmoles of H⁺

We neutralized all the OH⁻ but some H⁺ remain after the equilibrium

7.48 mmoles of H⁺ - 6.45 mmoles of OH⁻ = 1.03 mmoles of protons

Total volume is 50 mL + 29 mL = 79 mL

[H⁺] = 1.03 mmol / 79 mL → 0.0130 M

- log 0.0130 = 1.88 → pH

After equivalence point, pH will be totally acid, because we always have an excess of protons. Before the equivalence point, pH is basic, because we still have OH⁻ and these hydroxides, will be neutralized through the titration, as we add acid.

The pH value is given by 14 less the logarithm of the hydronium ion

concentration or the hydrogen ion concentration in the solution.

Responses (approximate values):

The pH values are;

A) 13.11

B) 12.91

C) 12.71

D) 12.42

E) 11.54

F) 7

G) 2.469

H) 1.884

A) Concentration of the KOH = 0.129 M

Amount of HCl added = 0.00 ml

The pH = -log[H⁺] = 14 - pOH

pOH = -log[OH⁻]

Which gives;

pH = 14 - (-log[OH⁻] )

B) Volume of acid added = 7.00 mL = 0.007 L

Concentration of the acid = 0.258 M HCl

Number of moles of acid, H⁺ = 0.007 × 0.258 moles = 0.001806 moles

Number of moles of KOH remaining, OH⁻= 0.05 × 0.129 - 0.001806 = 0.004644

Number of moles of OH⁻ = 0.004644 moles

[tex]Concentration, \ [OH^-] = \dfrac{0.004644 \, moles}{0.05 7 \, L} \approx \mathbf{ 0.0815 \, M}[/tex]

C) 12.5 mL HCl contains, 0.0125 × 0.258 moles = 0.003225 moles

OH⁻ remaining = 0.05 × 0.129 - 0.003225 = 0.003225 moles

[tex]Concentration \ of \ [OH^-]= \dfrac{0.003225\, moles}{(0.05 + 0.0125) \, L} = \mathbf{0.0516 \, M}[/tex]

D) 18.0 mL HCl contains, 0.018 × 0.258 moles = 0.004644 moles

OH⁻ remaining = 0.05 × 0.129 - 0.004644 = 0.001806 moles

[tex]Concentration \ of \ [OH^-] = \dfrac{0.001806\, moles}{(0.05 + 0.018) \, L} \approx \mathbf{0.0266\, M}[/tex]

E) 24.0 mL HCl contains, 0.024 × 0.258 moles = 0.006192 moles

OH⁻ ion remaining = 0.05 × 0.129 - 0.006192 = 0.000258 moles

[tex]Concentration \ of \ [OH^-] = \dfrac{0.000258\, moles}{(0.05 + 0.024) \, L} \approx \mathbf{0.0035\, M}[/tex]

F) 25.0 mL HCl contains, 0.025 × 0.258 moles = 0.00645 moles

[OH⁻] remaining = 0.05 × 0.129 - 0.00645 = 0 moles

[tex]Concentration \ of \ [OH^-] = \dfrac{0\, moles}{(0.05 + 0.024) \, L} \approx 0\, M[/tex]

Therefore;

Number of moles of KOH = 0, or the solution is neutralized

[OH⁻] = [H⁺]

Which gives;

G) 26.0 mL HCl contains, 0.026 × 0.258 moles = 0.006708 moles

[OH⁻] remaining = 0.05 × 0.129 - 0.006708 = -0.000258 moles

Therefore

Number of moles of H⁺ = 0.000258

[tex]\mathbf{Concentration} \ of \ \mathbf{[H^+] }= \dfrac{0.000258\, moles}{(0.05 + 0.026) \, L} \approx 0.003395\, M[/tex]

H) 29.0 mL HCl contains, 0.029 × 0.258 moles = 0.007482 moles

H⁺ remaining = 0.007482 - 0.05 × 0.129 = 0.001032 moles

Therefore

Number of moles of H⁺ = 0.001032

[tex]Concentration \ of \ [H^+] = \mathbf{ \dfrac{0.001032\, moles}{(0.05 + 0.029) \, L}} \approx 0.01306\, M[/tex]

Learn more about the pH of a solution here:

https://brainly.com/question/1195974

Answer:

Nice

Explanation: