If 20.6 grams of ice at zero degrees Celsius completely change into liquid water at zero degrees Celsius, the enthalpy of phase change will be positive. TRUE FALSE

The provided question is incomplete, however, the complete question is attached with answer:

Answer:

The correct answer is : option A. Beakers A and B contain an equal number of atoms.

Explanation:

No matter what is the element or substance, in one mole of any elemnet r metal or anything have 6.022×1023 everythings. So, beaker A have one mole of iron Fe and beaker B have one mole of Lead Pb, then the total atoms in each beaker will be equal that is :

1 mole of Fe =  1× 6.022×1023 atoms/mol

1 mole of Pb = 1× 6.022×1023 atoms/mol

Thus, the correct answer is: option A. Beakers A and B contain an equal number of atoms.

Answer:

pH of the buffer solution is 1.76

Explanation:

To find the pH of a buffer we can use Henderson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

Where pKa is -log Ka= 1.77 And [A⁻] is molar concentration of conjugate base, NaHSO₃ and [HA] molar concentration of weak acid, H₂SO₃

Replacing values of the problem:

pH = 1.77 + log [0.304M] / [0.310M]

pH = 1.76

Answer:

It is not 100% silver, but it contains a high percentage (more than the 98% for sure) of silver.

Explanation:

Hello,

In this case, since the density of silver is 10.49 g/cm³, we can substantiate if the given sample is silver by computing is density as shown below:

[tex]\rho =\frac{m}{V}=\frac{1.7kg}{0.164L}*\frac{1000g}{1kg} *\frac{1L}{1000cm^3}\\ \\\rho=10.37g/cm^3[/tex]

In such a way, since we find a slight difference in the computed density, we can say it is not 100% silver, but it contains a high percentage (more than the 98% for sure) of silver.

Regards.

Answer:

Explanation:

It should be noted that, the principle behind the ability of PLP to catalyze an amino acid transformation is greatly reduced if the OH substituent of pyridoxal phosphate is replaced by OCH3 is that; the OH is able to form a H-bond with the N which puts partial (+) on the N. This makes it easier for the AA to add to the imine C

OCH3 cannot make this H-bond w N

Answer:

False

Explanation:

Boron is an exception to the octet rule because it possesses less than eight electrons. Boron has five electrons with three of them being valence electrons and therefore has an incomplete octet. It readily forms compounds in which it has six valence electrons, rather than the usual eight.

Hope that helps.

Considering the exception to the octet rule, the statement is false because Boron is an exception to the octet rule and can take up to 6 electrons in its valence shell.

An exception to the octet rule is when there are too few valence electrons resulting in an incomplete octet. That is, the default exceptions imply that there can be covalently bonded atoms that surround themselves with fewer than eight electrons.

This exception occurs with boron. Boron has an incomplete octet because it only has six electrons around it. That is, boron has three valence electrons and can only form electron pair bonds in two locations, gaining stability only with 6 valence electrons.

In summary, the statement is false because Boron is an exception to the octet rule and can take up to 6 electrons in its valence shell.

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Answer:

23.71J is the work that the gas do.

Explanation:

The work that a gas do under isobaric conditions follows the formula:

W = P*ΔV

Where W is work in atmL, P is the pressure and ΔV is final volume -Initial volume In Liters

Replacing with the values of the problem:

W = P*ΔV

W = 0.600atm*(0.44000L - 0.0500L)

W = 0.234atmL

In Joules (1atmL = 101.325J):

0.234atmL × (101.325J / 1 atmL) =

Answer:

273.2

Explanation:

Answer:

pH = 4.56

Explanation:

The strychnine reacts with HCl as follows:

C₂₁H₂₂N₂O₂ + HCl ⇄ C₂₁H₂₂N₂O₂H⁺ + Cl⁻

For strychnine buffer:

pOH = 5.74 + log [C₂₁H₂₂N₂O₂H⁺] / [C₂₁H₂₂N₂O₂]

Initial moles of C₂₁H₂₂N₂O₂ are:

0.025L * (0.400 mol / L) = 0.01 moles C₂₁H₂₂N₂O₂

And of HCl are:

0.05L * (0.200 mol / L) = 0.01 moles HCl

That means after the reaction, you will have just 0.01 moles of C₂₁H₂₂N₂O₂H⁺ in 50mL + 25mL = 0.075L. And molarity is:

[C₂₁H₂₂N₂O₂H⁺] = 0.01 mol / 0.075L = 0.1333M

This conjugate acid, is in equilibrium with water as follows:

C₂₁H₂₂N₂O₂H⁺(aq) + H₂O(l) ⇄ C₂₁H₂₂N₂O₂ + H₃O⁺

Where Ka = Kw / Kb = 1x10⁻¹⁴ / 1.8x10⁻⁶ = 5.556x10⁻⁹

Ka is defined as:

Ka = 5.556x10⁻⁹ = [C₂₁H₂₂N₂O₂] [H₃O⁺] / [C₂₁H₂₂N₂O₂H⁺]

In equilibrium, concentrations are:

C₂₁H₂₂N₂O₂ = X

H₃O⁺ = X

C₂₁H₂₂N₂O₂H⁺ = 0.1333M - X

Replacing in Ka expression:

5.556x10⁻⁹ = [X] [X] / [0.1333M - X]

7.39x10⁻¹⁰ - 5.556x10⁻⁹X = X²

7.39x10⁻¹⁰ - 5.556x10⁻⁹X - X² = 0

Solving for X:

X = - 2.72x10⁻⁵M → False solution. There is no negative concentrations

X = 2.72x10⁻⁵M → Right solution.

As H₃O⁺ = X

H₃O⁺ = 2.72x10⁻⁵M

And pH = -log H₃O⁺

Answer:

dark red

Explanation:

because dilute hcl is acid

dark red is the correct answer.

Answer:I’m here for points

Explanation:yeah cuz

Answer:

d

Explanation:

The only hypothesis that is testable using the scientific method would be that all swans are white.

The scientific method involves a series of steps through which scientists are able to arrive at a conclusion about the natural world. The steps include observation, drawing up falsifiable hypotheses from observations, testing the hypotheses using experiments, and then arriving at conclusions based on the data gathered from the experiment.

There is no way to test the mortality of all men as this will require harming humans in order to prove their mortality. The best color is also subjective as individuals have their preference when it comes to color. There is no way to prove the hypothesis that no life exists on other planets as this will require visiting other planets, a gesture that is practically impossible. That swimming is fun can also be subjective. Not everyone finds swimming interesting.

The hypothesis that all swans are white can be tested by sampling the population of swans in different areas and recording their colors objectively.

Hence, the correct option is d.

The hypothesis 'all swans are white' is testable by using the scientific method (Option d).

In conclusion, the hypothesis 'all swans are white' is testable by using the scientific method (Option d).

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Answer:

It loses thermal energy and the movement of particles decreases.

Explanation:

The process of a gas turning to a solid is called condensation.

Explanation:

Hey, there!!

Your question is,

Magnesium + sulphuric acid = magnesium + hydrogen gas.

I.e.

[tex]mg + h2so4 = mgso4 + h2 \: [/tex]( hydrogen gas)

Here,

reactant and product have equal atoms.

so, it is alreday balanced.

They all are equal and alredy balanced.

Hope it helps...

Answer:

Mg + H2SO4 → MgSO4 + H2

Explanation:

The chemical equation shows magnesium (Mg) and sulfuric acid (H2SO4) on one side and magnesium sulfate (MgSO4) and hydrogen gas (H2) on the other.

Mg + H2SO4 → MgSO4 + H2

Answer:

1. spontaneous

2. spontaneous

3. Not Spontaneous

4. Not Spontaneous

Palladium and Sn^4+ can be reduced by hydrogen.

Explanation:

If we look at the electrochemical systems represented above, we will notice that in the first two cells, the metal should be reduced looking at the positive electrode potential of the process. This means that hydrogen can reduce the both metals. Electrons flow from the H2(g)/H^+(aq) half cell to the metal/metal ion half cell.

Similarly, when the standard electrode potential is negative, electrons flow from the metal/metal ion electrode to the hydrogen electrode.

Based on the reaction equations, a process is spontaneous if it gives a positive E°cell hence the answers above.

Answer:

Value = 1.80 g/cm³ (Approx)

Explanation:

Given:

[tex]\frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(1.65 \times 10^2 cm)^3}[/tex]

Computation:

[tex]\frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(1.65 \times 10^2 cm)^3} \\\\\frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(4.492125 \times 10^6 cm^3)} \\\\ \frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(4.492125 \times 10^6 cm^3)}\\\\ \frac{3.39 \times 10^7g}{18.8166132\times 10^6 cm^3} \\\\ 1.80159945g/cm^3[/tex]

Value = 1.80 g/cm³ (Approx)

The density has been calculated by computing the equation as [tex]\rm 1.802\;g/cm^3[/tex].

The calculation has been performed for density, as it has been performed for mass per unit volume.

The calculations can be performed as:

[tex]\rm \implies \dfrac{3.39\;\times\;10^7\;g}{\frac{4}{3}\;\times\;(3.1416)\;(1.65\;\times\;10^2)^3\;cm^3 } \\\implies \dfrac{3.39\;\times\;10^7\;g}{\frac{4}{3}\;\times\;(3.1416)\;(4.49\;\times\;10^6)\;cm^3 }\\\implies \dfrac{3.39\;\times\;10^7\;g}{\frac{4}{3}\;\times\;14.1124\;\times\;10^6\;cm^3 }\\[/tex]

The equation has been further simplified for density as:

[tex]\rm \implies \dfrac{3.39\;\times\;10^7\;g}{18.811\;\times\;10^6\;cm^3 } \\\implies 1.802\;g/cm^3[/tex]

The density has been calculated by computing the equation as [tex]\rm 1.802\;g/cm^3[/tex].

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Answer: 0.4g per 1 cm3

Explanation:

5.0 × 3.0 × 7.0 = 105 cm3 this is the volume of cube

density is mass per unit of volume

d = m / V then 42g / 105 cm3 = 0.4 g/ 1 cm3

Answer:

Odour is intensive

Explanation:

intensive properties are Independent of the amount of matter

Answer:

A piece of metal is placed in water and produces sparks and gas.

The sign of a chemical reaction has occurred is a piece of metal is placed in water and produces sparks and gas. The correct option is B.

Chemical changes, often known as chemical reactions, are the transformation of one or more compounds into one or more brand-new, separate substances. In other words, a chemical change is a process based on atomic rearrangement.

Metal is malleable and luster substance. They are gold, silver, magnesium, etc. They are present in the periodic table. Furthermore, they are highly reactive and soft.

A chemical reaction is happening in the reaction of water when it produces a spark or gas when reacting with another substance.

Thus, the correct option is B. A piece of metal is placed in water and produces sparks and gas.

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#SPJ2

Answer:

157.2 mL

Explanation:

The following data were obtained from the question:

Density (D) of liquid = 0.878 g/mL

Mass (m) of liquid = 138 g

Volume (V) of liquid =.?

Density of a substance is simply defined as the mass of the substance per unit volume of the substance. Mathematically, it is expressed as:

Density (D) = mass /volume

D = m/V

With the above formula, we can obtain the volume of the liquid as follow:

Density (D) of liquid = 0.878 g/mL

Mass (m) of liquid = 138 g

Volume (V) of liquid =.?

D = m/V

0.878 = 138/V

Cross multiply

0.878 × V = 138

Divide both side by 0.878

V = 138/0.878

V = 157.2 mL

Therefore, 157.2 mL of the liquid must be provided.

Answer:

is a plot showing the change in ph of the solution in the conical flask as the reagent is added from the burette

Explanation:

like, the ph of the solution at equivalence point is dependent on the strenght of the acid and strenght of the base used in the titration

Answer:

0.002079 M

Explanation:

2 C2F4 → C4F8

Using the differential rate equation, we have;

-d[A] / dt = k x [A]²

Where [A] represent concentration of reactant; C2H4.

Upon collecting like terms we have;

(1 / [A]²) d[A] = -k x dt

Integrating both sides;

∫(1 / [A]²) d[A] = ∫-k dt

This leaves us with;

-1/[A] + 1 / [Ao] = -k ∆t

Where [A] = Final Concentration, [Ao] = Initial concentration

Arranging the equation gives us;

1 / [A] = 1 / [Ao] + k ∆t

Time = 3 hours = 10800 s (upon converting to seconds)

Inserting the values, we have;

1 / [A] = 1 / (0.105 moles / 4 L) + (0.0410 M−1 s −1 ) x (10800s)

1 / [A] =  = 38.10 + 442.8 = 480.9

[A] = 0.002079 M

The concentration of C2F4 units of M is 0.0021 M.

The molarity of the solution of C2F4 is obtained from;

Molarity = Number of moles/volume

Number of moles = 0.105 mol

Volume =  4.00 L

Molarity = 0.105 mol/ 4.00 L = 0.026 M

Recall that the reaction is second order hence;

1/[A] = kt + 1/[Ao]

[A]  = concentration of  C2F4 at time = t

[Ao] = Initial concentration of C2F4

k = rate constant

t = time taken

1/[A] = (0.0410 × 10800) + 1/ 0.026

[A] = 0.0021 M

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Answer:

A. The charge of the nuclide

B. The atomic number of the nuclide

C. The number of protons in the nuclide

Explanation:

The general nuclide symbol is in the picture.

Where X is the element you want to represent, A the mass number (That is mass of protons + mass of neutrons), Z is atomic number (Number of protons), and C is the charge of the nuclide.

Thus, you can determine from the nuclide symbol:

A. The charge of the nuclide . YES. Is C.

B. The atomic number of the nuclide . YES. Is Z.

C. The number of protons in the nuclide . YES. From the difference of A - Z.

D. The number of isotopes of that element. NO. It is not possible to determine number of isotopes of an element from a nuclide symbol.

Answer:

DUDE YOUR ANSWER IS:

Explanation:

GIVEN BY YOU:

[H+]=(1*10^-6)

Taking negitive log on both sides we get,

-㏒[H+]=-㏒(1*10^-6)

now by power rule of exponent, and also we know that

-㏒[H+]=PH so we get

PH= -(-6)(log(10))

as we know log(10)=1 hence by putting we get

PH=6

acidic or a basic solution:

as PH<7 hence its acidic

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so other get help of it

Answer:

6.25 ×10^10 Hz

Explanation:

If the distance between five successive crests is 2.4 cm, then the distance between each crest is 2.4/5 = 0.48 cm or 0.0048 m or 4.8 ×10^-3 m

Since the velocity of a wave is given by;

v= λf

Where;

λ= wavelength of the wave

f= frequency of the wave

But λ= distance between successive crests = 4.8 ×10^-3 m

v= 3×10^8 ms-1 (speed of electromagnetic waves in vacuum)

f= v/λ

f= 3×10^8 ms-1/4.8 ×10^-3 m

f= 0.625 ×10^11 Hz

f= 6.25 ×10^10 Hz

Answer:

You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you use to determine which type of change is occurring?

If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.

Sample Response: If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.

What did you discuss in your response? Check all that apply.

the production of an odor

a change in energy

a change in color

the formation of a solid

the formation of new substances

a change in properties and identities

A chemical change may result in the following;

A Physical change may result in the following;

A chemical change leads to the formation of a new substance. This implies that the composition of the substance has being changed.

A physical change does not lead to a change in the nature of the substance. However, the appearance, shape, texture or size of the substance may change.

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