Can someone help me with these?

Answer:

hydroxide ion

Explanation:

because base produce hydroxide ion when dissolved in water

Answer:

Heat absorbed = mS△T

51 = ( 8.2/1000)Kg ×S (11.5)

51×1000= 8.2 (11.5)S

S = 51000/94.3

S = 540.8 J/kg K

Answer:

Energy released =  18.985 J

Explanation:

The  exponential decay of radioactive substance is given by -

N(t) = N₀ [tex]e^{-kt}[/tex]

where

N₀ = initial quantity

k = decay constant

Half life, [tex]t_{1/2} = \frac{ln 2}{k}[/tex]

⇒[tex]k = \frac{ln 2}{t_{1/2} }[/tex]

Given,

N₀ = 12.5 + 3 = 15.5 × 10⁻⁶ gm

[tex]t_{1/2}[/tex] = 32.6 + 18 = 50.6 × 10⁶ years

So,

[tex]k = \frac{ln 2}{50.6 * 10^{6} }[/tex] = 1.361 × 10⁻⁸ year⁻¹

Now,

N(1) = 15.5 × 10⁻⁶  [tex]e^{-1.361*10^{-8} *1}[/tex]

      = 15.49999978904

Now,

Substance decayed = N₀ - N(t)

                                 = 15.5 × 10⁻⁶ - 15.49999978904 × 10⁻⁶

                                 = 21.095 × 10⁻¹⁷ kg

⇒Δm = 21.095 × 10⁻¹⁷ kg

So,

Energy released = Δmc²

                           = 21.095 × 10⁻¹⁷ × 3 ×10⁸ × 3 × 10⁸

                          = 189.855 ×10⁻¹

                          = 18.985 J

⇒Energy released =  18.985 J

Answer:

0.01125

Explanation:

:b

Answer:

The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from

n

i

=

2

to

n

f

=

6

.

A good starting point here will be to calculate the energy of the photon emitted when the electron falls from

n

i

=

6

to

n

f

=

2

by using the Rydberg equation.

1

λ

=

R

⋅

(

1

n

2

f

−

1

n

2

i

)

Here

λ

si the wavelength of the emittted photon

R

is the Rydberg constant, equal to

1.097

⋅

10

7

m

−

1

Plug in your values to find

1

λ

=

1.097

⋅

10

7

.

m

−

1

⋅

(

1

2

2

−

1

6

2

)

1

λ

=

2.4378

⋅

10

6

.

m

−

1

This means that you have

λ

=

4.10

⋅

10

−

7

.

m

So, you know that when an electron falls from

n

i

=

6

to

n

f

=

2

, a photon of wavelength

410 nm

is emitted. This implies that in order for the electron to jump from

n

i

=

2

to

n

f

=

6

, it must absorb a photon of the same wavelength.

Answer:

=KSO4+Na2(NO3)2

Explanation:

the answer is true using this chemical equation balancer

Answer:

Explanation:

The law of multiple proportions.

Answer:

it is 0.50=0.5 M

Explanation:

Molarity definition is measure the concentration of solution.

and the rule is

molarity(M)= moles of solute/volume of solution in liters

Ex: 2.1 M MgCl2= 2.1 mole MgCl2/ L MgCl2 solution

Answer:

no sure

Explanation:

Answer:

Dipole induced dipole force of attraction.

Explanation:

This is because dipole induced dipole attraction is a weak force of attraction or london force that occur when a polar molecule causes a form induction in a dipole in an atom or in a nonpolar molecule by altering the arrangement non polar electrons.

Answer:

The Answer is gonna be Indroduction of non-native plant species

Answer:

4

Explanation:

From the options provided the result of the error is ( A ) ; The buffer will have a lower capacity because of the smaller number of moles of  HF and F⁻ available to react if an acid or base is added.

Considering the acid ionization equilibrium for the weak acid HF.

A buffer solution is a solution that its PH value remains unchanged when a small amount of acid or base to added to the solution, therefore when the moles of acid or base present in the buffer solution is high enough the buffer solution will have a high buffer capacity. from the mistake of the student the number of moles present is lesser which means that the buffer solution will have a lower capacity

Hence the buffer will have a lower capacity because of the smaller number of moles of HF and F⁻ available to react is an acid or base is added.

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Answer:

c

Explanation:

this is because it makes sense

Answer:

d

Explanation:

Answer:

Bicarbonate neutralizes the acidity of Lidocaine and hence reduce the pain

Explanation:

Alkalinization by addition of sodium bicarbonate causes buffering of local anesthetics and hence produce faster anesthetic effect such as pain control, pain reduction while injecting the patient and  faster onset of local anesthetics.

Lidocaine along with epinephrine results into acidic compound wit respect to subcutaneous tissue. Hence, when bicarbonate is added, it neutralizes the acidity of Lidocaine and hence decrease the pain.  

Answer:

a.Provide the body which shape and protection.

Explanation:

Bones usually gives us shape as well as protects our innner organs.

so if it helps don't forget to like and Mark me

Answer:

A

Explanation:

Each DNA sequence that contains instructions to make a protein is known as a gene. The size of a gene may vary greatly, ranging from about 1,000 bases to 1 million bases in humans.

Answer:

Wavelength (typically measured in nanometers) is the distance between two points in a wave.Frequency (typically measured in Hertz) is the number of waves in a specific time . Frequency and wavelength have both direct and inverse relationships. The crucial difference between frequency and wavelength is that frequency shows the total number of wave oscillations in a given time. As against wavelength specifies the distance between two specific points of a wave.

Explanation:

Frequency is how often something changes per second be it amplitude of a voltage on a wire or be it the bobbing back and forth of a bobblehead. Frequency is how often something moves up and down in a second. If a bobble head moves forward and backward in one second then it has a bobbling frequency of 1 Hertz (Hz). The unit of frequency is Hertz (Hz) or # of cycles or oscillations per second. A wavelength is measured in distance like meters (m). For photons or light or radiowaves the equation is wavelength=speed of light/frequency.

Answer:

Wavelength (typically measured in nanometers) is the distance between two points in a wave, while frequency is how often something changes per second be it amplitude of a voltage on a wire or be it the bobbing back and forth of a bobblehead.

Answer:

[tex]\Delta H_{comb}=2043.85kJ/mol[/tex]

Explanation:

Hello there!

In this case, according to the given chemical reaction, it possible for us to set up the expression for the calculation of the enthalpy change as shown below:

[tex]\Delta H_r=-\Delta H_{comb}=3\Delta _fH_{CO_2}+4\Delta _fH_{H_2O}-\Delta _fH_{C_3H_8}-3\Delta _fH_{O_2}[/tex]

Thus, given the values of the enthalpies of formation on the attached file, we obtain:[tex]-\Delta H_{comb}=3(-393.5kJ/mol)+4(-241.8kJ/mol)-(-103.85kJ/mol)-3(0kJ/mol)\\\\-\Delta H_{comb}=-2043.85kJ/mol\\\\\Delta H_{comb}=2043.85kJ/mol[/tex]

Best regards!

Answer:

false

Explanation:

A compound has the combined properties of the elements from which it is made. Atoms show the macro properties of an element.

Answer:

because we need it to breathe

Explanation:

we breathe in oxygen and release carbon dioxide

Answer:

Ok i have a really weird theory.

Oxygen actually kills us we just don't know it yet. We need it too live but something in it also poisons us and causes us to die in around 100 years from birth. that's why we all die

real answer

we need it to breathe, when we breath we inhale in oxygen and release carbon dioxide which allows trees to grow and they produce more oxygen. We cant rely on anything else because oxygen is important and without it we die. Oxygen is one of the purist airs.

Answer:

6.12 L

Explanation:

Given that,

Initial volume, V₁ = 5 L

Initial temperature, T₁ = 7.0°C = 343 K

Final temperature, T₂ = 147°C = 420 K

We need to find its new volume. The relation between volume and temperature is given by :

[tex]\dfrac{V_1}{T_1}=\dfrac{V_2}{T_2}\\\\V_2=\dfrac{V_1T_2}{T_1}\\\\V_2=\dfrac{5\times 420}{343}\\\\V_2=6.12\ L[/tex]

So, the new volume is 6.12 L.

Answer:

I do not know the Answer I'm just trying to get my point

Explanation:

Thank You

The two realistic demands protestors could bring forward in their peaceful protest include:

Thus it is referred to an individual which publicly demonstrates opposition to something.One of the roles of the government is to protect lives and properties.

Making realistic demands during a peaceful protest is looked into in most cases.

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Answer:

Explanation:

Convert molecules to moles:

1 mole of NaNO₃= 6.02 x 10^23 molecules of NaNO₃

7.3 x10^24/(6.02 x 10^23)=12mol NaNO₃

Find molar mass:

NaNO₃=1 mole of Na and 1mole of N and 3mole of O

Find grams:

14.01g x 12= 168.12 g of N

Answer:

[tex]V_1=7.5L[/tex]

Explanation:

Hello there!

In this case, according to the Charles' law equation which help us to understand the directly proportional relationship between volume and temperature:

[tex]\frac{V_2}{T_2}= \frac{V_1}{T_1}[/tex]

Thus, by solving for the initial volume, V1, and making sure we use the temperatures in Kelvin, we can calculate the final volume as shown below:

[tex]V_1= \frac{V_2T_1}{T_2} \\\\V_1= \frac{5.0L*(147+273)K}{(7.0+273)K} \\\\V_1=7.5L[/tex]

Best regards!

Answer:

a) the final temperature of the air is 500° R

b) the amount of specific entropy produced is 0.0758 Btu/lb-°R  

Explanation:

Given the data in the question;

Air at 500° R = [tex]T_i[/tex]

Using first law of thermodynamic;

δQ = dU + W

now, since the vessel is insulated, the transfer is zero, work done also is zero since there is also no external work done.

δQ = dU + W

0 = dU + 0

dU = 0

[tex]u_f[/tex] - [tex]u_i[/tex] = 0

[tex]u_f[/tex] = [tex]u_i[/tex]

hence, change in internal energy is 0

Now, since the ideal internal energy is a function of temperature, the temperature will also remain the same;

[tex]T_f = T_i[/tex]

F = 500° R

Therefore, the final temperature of the air is 500° R

b)

given that; initial volume is one-third of the total volume

V₁ = [tex]\frac{1}{3}[/tex]V₂

3V₁ = V₂

3 = V₂/V₁

Now, we take the value of gas constant R from air property table;  gas constant R = 0.069 Btu/lb-R  

so we calculate the entropy change;

Δs = [tex]c_v[/tex]In( [tex]\frac{T_2}{T_1}[/tex] ) + R.In( [tex]\frac{V_2}{V_1}[/tex] )

we substitute

Δs = [tex]c_v[/tex]In( [tex]\frac{500}{500}[/tex] ) + 0.069 × In( 3 )

Δs = 0 + [0.069 × In( 3 )]

Δs = 0 + [0.069 × 1.0986]

Δs = 0.0758 Btu/lb-°R  

Therefore, the amount of specific entropy produced is 0.0758 Btu/lb-°R  

Insulated vessels separate the environment of the outer and the inner system. The final temperature is 500 degrees R and 0.0758 Btu/lb- degree R is the entropy.

The temperature is the measure of the hot or the coldness of the system.  The first law of the thermodynamics is used to measure the final temperature of the system:

[tex]\rm \Delta Q = \rm \Delta U + W[/tex]

The work done will be zero as the system is insulated and no external work is being done.

[tex]\begin{aligned} \rm 0 &= \rm \Delta U + 0\\\\\rm U_{f} - U_{i} &= 0\\\\\rm U_{f} &= \rm U_{i} \end{aligned}[/tex]

Hence, the change in the internal energy is zero. Thus, the final temperature will remain the same,

[tex]\rm T_{f} = \rm T_{i} = 500 ^{\circ} \rm R[/tex]

Now, as we know, the initial volume is one-third of the total volume then,

[tex]\begin{aligned} \rm V_{1} &= \rm \dfrac{1}{3} V_{2}\\\\\rm 3V_{1}&= \rm V_{2}\\\\3 &= \rm \dfrac{V_{1}}{V_{2}}\end{aligned}[/tex]

The change in entropy is calculated as:

[tex]\begin{aligned} \rm \Delta S &= \rm C_{v} ln ( \dfrac{T_{2}}{T_{1}}) + R \times ln ( \dfrac{V_{2}}{V_{1}}) \\\\&= 0 + [0.069 \times \rm ln( 3 )]\\\\& = 0.0758 \;\rm Btu/lb-^{\circ}R \end{aligned}[/tex]

Therefore, the entropy produced is 0.0758 Btu/lb- degree R.

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Answer:

0.20 g/L

Explanation:

Step 1: Calculate the molar mass of the gas (M)

At T = 350 °C = 623 K and P = 1 atm (we will assume this data), the density (ρ) of the gas is 0.087 g/L. We can calculate the molar mass of the gas using the following expression.

ρ = P × M/R × T

M = ρ × R × T/P

M = 0.087 g/L × (0.0821 atm.L/mol.K) × 623 K/1 atm = 4.5 g/mol

Step 2: Calculate the density of the gas at STP

At standard temperature (T = 273.15 K) and standard pressure (P = 1 atm), the density of the gas is:

ρ = P × M/R × T

ρ = 1 atm × 4.5 g/mol /(0.0821 atm.L/mol.K) × 273.15 K = 0.20 g/L