Draw Lewis symbols for the most stable ton formed by: sodium, oxygen, calcium, and chlorine.

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:

9th:08473 kJ/mol

Explanation:

HAHAHAHAHAHAHAHAHAHA

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: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:

Explanation:

D or b

Sorry if wrong

Answer:

temporal

Explanation:

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:

A. Beginning of the spring

Explanation:

Pa like, Pa follow, Pa rate

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:

C9H19 C5H12 C6H17 C7H20

Answer:

mesure it

Explanation:

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:

Answer:

yes solution is always a mixture but not all mixtures are solution

Explanation:

A solution.is a homogeneous mixture of substance that have uniform composition throughout

And a mixture hVe twoo or more substances that are not chemically.combine

Answer:

a. Endothermic

b. 26.37kJ/mol

Explanation:

a. As we can see, the temperature of the water is decreasing when the reaction is occurring, that means the reaction is absorbing heat and is endothermic

b. To find the enthalpy we must find the change in heat when 12.1g of KCl are dissolved. Using the equation:

Q = -m*ΔT*C

Where Q is change in heat

m the mass of solution (250g + 12.1g = 262.1g)

ΔT is change in heat (17.1°C - 21.0°C = -3.9°C)

And C is specific heat of the solution (4.184J/g°C assuming is the same than the specific heat of water).

Replacing:

Q = -262.1g*-3.9°C*4.184J/g°C

Q = 4277J = 4.28kJ

As reaction enthalpy is the change in heat per mole of reaction, we must find the moles of 12.1g of KCl:

Moles KCl -Molar mass: 74.55g/mol-:

12.1g KCl * (1 mol / 74.55g) = 0.1623 moles KCl

The reaction enthalpy us:

4.28kJ / 0.1623mol = }

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

Ce clasă ești sa văd daca te pot ajuta

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:

[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:

diiodo????

Explanation:

recheck the question and resend

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:

rain

Explanation:

The volcanic eruptions may add salt to ocean waters. option A is correct.

Volcanic eruption produces or releases direct minerals into the water or in the ocean and salt domes are also responsible to increase the salt concentration in the water.

Two of the most commonly found ions in the water of oceans are chloride ions and sodium ions. 85% of the concentration found remaining are the magnesium and sulfate salts.

This process also happens with the mountains but in oceans it invertases the concentration of salt.  

Therefore, volcanic eruptions may add salt to ocean waters. option A is correct.

Learn more about volcanic eruptions, here :

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#SPJ2

Answer:

The ATP is broken down into glucose which the cells use for energy.

Answer:

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

Answer:

c

Explanation:

hope this helps! ^-^

Answer:

C

Explanation:

It's the answer

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 .

Answer:

Nice

Explanation:

Explanation:

momentum increases with an increase in mass and velocity

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

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]

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Answer:

true

Explanation:

you are getting closer to the core hope this helps!