The specific heat of palladium is 0.239 J/g°C. How much heat (q) is released when a 10.0 g piece of platinum cools from 100.0°C to 50.0°C?

Solution :

The partition coefficient

[tex]$k_d= \frac{\text{(mass of caffeine in }CH_2Cl_2 / \text{volume of }CH_2Cl_2)}{\text{(mass of caffeine in water/ volume of water)}}$[/tex]

   = 9.0

A). 1 x 200 mL extraction

Let m be the mass of caffeine in water

Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m

∴ [tex]$\frac{(100-m)/200}{m/200}=9$[/tex]

  [tex]$\frac{100-m}{m}=9$[/tex]

  [tex]$10 \ m = 100$[/tex]

[tex]$m=\frac{100}{10}$[/tex]

     = 10

Therefore, the mass remaining in the coffee is m = 10 mg

B). 2 x 100 mL extraction

First extraction :

Let [tex]$m_1$[/tex] be the mass of the caffeine in water.

Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 100 - m

∴ [tex]$\frac{(100-m_1)/100}{m_1/200}=9$[/tex]

  [tex]$\frac{100-m_1}{m_1}=9$[/tex]

  [tex]$5.5 \ m_1 = 100$[/tex]

[tex]$m_1=\frac{100}{5.5}$[/tex]

     = 18.18

Mass remaining in the coffee after the 1st extraction [tex]$m_1$[/tex] = 18.18 mg

Second extraction:

Let [tex]$m_2$[/tex] be the mass of the caffeine in water.

Mass of caffeine in [tex]$CH_2Cl_2$[/tex] = 18.18 - [tex]$m_2$[/tex]

∴ [tex]$\frac{(18.18-m_2)/100}{m_2/200}=9$[/tex]

  [tex]$\frac{18.18-m_2}{m_2}=9$[/tex]

  [tex]$5.5 \ m_2 = 18.18$[/tex]

[tex]$m_1=\frac{18.18}{5.5}$[/tex]

     = 3.3

Mass remaining in the coffee after the 1st extraction [tex]$m_2$[/tex] = 3.3 mg

Answer:

The answer is "[tex]\bold{21.616\ \ \frac{J}{mol K}}[/tex]".

Explanation:

when it is a constant pressure:

[tex]Cp= \frac{\Delta q}{n\Delta T} \\\\[/tex]

[tex]=\frac{229}{3\times 2.55}\\\\=\frac{229}{7.65}\\\\=29.93 \frac{J}{mol\ K}\\[/tex]

and,  

[tex]Cp-Cv=R\ \ (Mayer's\ formula)[/tex]

then,

[tex]Cv=Cp-R\\\\[/tex]  

    [tex]=29.93-8.314\\\\=21.616\ \ \frac{J}{mol K}[/tex]

Answer:

The solution with [OH-] = 3.2x10-3 M will have an [H+] of 3.09x10–12 M.Explanation:

Answer:first part is A and C, second part is C, third part is 40 m/s and the fourth part is zero

Explanation: I guessed and got them right lol

Answer:

The answer is 10cm^3

Explanation:

5x1x2=10

Mind marking me brainliest? :)

1 becasuevof one vvalence shell

Answer:

11.4

Explanation:

Density = Mass / Volume

Density = 35.4 / 3.11

Density = 11.38263666

As there are more number of digits after the decimal, you can round it to 3 significant figure.

Now, your value will be:

Density = 11.4

Photoelectric effect, phenomenon in which electrically charged particles are released from or within a material when it absorbs electromagnetic radiation.

mark me brainliestt :))

A solution is prepared by mixing 50.00 mL of 0.100 M HNO3 and 100.00 ml of 0.200 M Ca(NO3)2. The molarity of the nitrate ion in the final solution is 0.1667 M.

The amount of a substance in a specific volume of solution is known as its molarity (M). The number of moles of a solute per liter of a solution is known as molarity. The molar concentration of a solution is another name for molarity.

Molarity (M), which is determined by dividing the solute's mass in moles by the volume of the solution in liters, is the most widely used unit to express solution concentration: liters of solution/moles of solute equals M. One liter of a solution with a 1.00 molar concentration (1.00 M) contains 1.00 moles of solute.

50.0 mL x 0.100 M

= 5.00 millimoles of HNO3

=0.00500 moles

100.0 mL x 0.200 M

= 20.0 millimoles of HNO3

=0.0200 moles

The whole solution has a volume of 150.0 mL

= 50.0+100.0

= 150

The whole solution contains 25.0 millimoles of HNO3

= 5.00+20.0

= 25

millimoles / mL = Molarity

25.0 / 150.0

= 0.1667 M

moles / Liters = Molarity

0.0250 / 0.1500

= 0.1667 M

Thus, The molarity of the nitrate ion in the final solution is 0.1667 M.

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Answer:

Respiration

Explanation:

Energy, steam and carbondioxide formed.

Answer:

El cloruro de litio se utiliza para fabricar litio metálico. El cloruro de litio se funde y electroliza. Esto produce litio metálico líquido.

Explanation:

sowwy si mi español es malo

Answer:

give him brainliest

Explanation:

The group corresponding to alkali metal, alkali earth metal, halogen, and noble gas is IA,IIA, 17, 18 group respectively.

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Answer:

4. D sounds like the best option.

5. D is the correct answer.

Explanation:

You're Welcome

Answer:

The right approach is "80 g".

Explanation:

Given:

[tex]L_f=80 \ Cal/g[/tex]

[tex]L_v=540 \ Cal/g[/tex]

[tex]S=1 \ Cal/g[/tex]

Now,

The amount of heat cooling will be:

= [tex]mL_v+mS \Delta T[/tex]

= [tex](10\times 540)+10\times 1\times (100-0)[/tex]

= [tex]5400+1000[/tex]

= [tex]6400 \ Cal[/tex]

then,

⇒ [tex]m_{ice} L_f=6400[/tex]

[tex]m_{ice}\times 80=6400[/tex]

        [tex]m_{ice}=\frac{6400}{80}[/tex]

                [tex]=80 \ g[/tex]            

Explanation:

The self-ionization of water (also autoionization of water, and autodissociation of water) is an ionization reaction in pure water or in an aqueous solution, in which a water molecule, H2O, deprotonates (loses the nucleus of one of its hydrogen atoms) to become a hydroxide ion, OH−. The hydrogen nucleus, H+, immediately protonates another water molecule to form hydronium, H3O+. It is an example of autoprotolysis, and exemplifies the amphoteric nature of water

Animation of the self-ionization of water

Chemically pure water has an electrical conductivity of 0.055 μS/cm. According to the theories of Svante Arrhenius, this must be due to the presence of ions. The ions are produced by the water self-ionization reaction, which applies to pure water and any aqueous solution:

H2O + H2O ⇌ H3O+ + OH−

Expressed with chemical activities a, instead of concentrations, the thermodynamic equilibrium constant for the water ionization reaction is:

{\displaystyle K_{\rm {eq}}={\frac {a_{\rm {H_{3}O^{+}}}\cdot a_{\rm {OH^{-}}}}{a_{\rm {H_{2}O}}^{2}}}}

which is numerically equal to the more traditional thermodynamic equilibrium constant written as:

{\displaystyle K_{\rm {eq}}={\frac {a_{\rm {H^{+}}}\cdot a_{\rm {OH^{-}}}}{a_{\rm {H_{2}O}}}}}

under the assumption that the sum of the chemical potentials of H+ and H3O+ is formally equal to twice the chemical potential of H2O at the same temperature and pressure.[1]

Because most acid–base solutions are typically very dilute, the activity of water is generally approximated as being equal to unity, which allows the ionic product of water to be expressed as:[2]

{\displaystyle K_{\rm {eq}}\approx a_{\rm {H_{3}O^{+}}}\cdot a_{\rm {OH^{-}}}}

In dilute aqueous solutions, the activities of solutes (dissolved species such as ions) are approximately equal to their concentrations. Thus, the ionization constant, dissociation constant, self-ionization constant, water ion-product constant or ionic product of water, symbolized by Kw, may be given by:

{\displaystyle K_{\rm {w}}=[{\rm {H_{3}O^{+}}}][{\rm {OH^{-}}}]}

where [H3O+] is the molarity (≈ molar concentration)[3] of hydrogen or hydronium ion, and [OH−] is the concentration of hydroxide ion. When the equilibrium constant is written as a product of concentrations (as opposed to activities) it is necessary to make corrections to the value of {\displaystyle K_{\rm {w}}} depending on ionic strength and other factors (see below).[4]

At 25 °C and zero ionic strength, Kw is equal to 1.0×10−14. Note that as with all equilibrium constants, the result is dimensionless because the concentration is in fact a concentration relative to the standard state, which for H+ and OH− are both defined to be 1 molal (or nearly 1 molar). For many practical purposes, the molal (mol solute/kg water) and molar (mol solute/L solution) concentrations can be considered as nearly equal at ambient temperature and pressure if the solution density remains close to one (i.e., sufficiently diluted solutions and negligible effect of temperature changes). The main advantage of the molal concentration unit (mol/kg water) is to result in stable and robust concentration values which are independent of the solution density and volume changes (density depending on the water salinity (ionic strength), temperature and pressure); therefore, molality is the preferred unit used in thermodynamic calculations or in precise or less-usual conditions, e.g., for seawater with a density significantly different from that of pure water,[3] or at elevated temperatures, like those prevailing in thermal power plants.

We can also define pKw {\displaystyle \equiv } −log10 Kw (which is approximately 14 at 25 °C). This is analogous to the notations pH and pKa for an acid dissociation constant, where the symbol p denotes a cologarithm. The logarithmic form of the equilibrium constant equation is pKw = pH + pOH.

Answer: 6.0g x 1 mol/18.02g x 40,65 kJ/mol which is D

Explanation: Just did

The water vapors change from vapor into water in condensation. The energy released by 6 gm of water is 6.0 g x 1 mol/18.02 g x 40.65 kJ/mol. Thus, option D is correct.

The heat of vapourization is the latent heat or enthalpy needed by the liquid to get converted into the vapor or the gaseous phase of the matter. It can be used to determine the energy released or absorbed by the substance.

The heat of vapourization of water is 40.65 kJ/mol, and its molar mass is 18.02 moles.

So, the energy released for the water when it is condensed into vapors will be,

6.0 g x 1 mol/18.02 g x 40.65 kJ/mol

Therefore, the heat of vapourization determines the amount of energy released.

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Answer:

B

Explanation:

Answer:

c. The N2 molecules collide more frequently with the walls of the flask than do the Ar atoms.

Explanation:

The statements are:

a. There are more molecules of N2 present than atoms of Ar. FALSE. Because 1 mol of molecules of N2 = 28g and 1 mol of molecules of Ar = 40g. As there are equal MASSES, you will have more molecules of N2 than Ar molecules

b. The pressure is greater in the Ar flask. FALSE

Because pressure is directly proportional to amount of molecules. As molecules N2 > Molecules Ar. The pressure is greater in N2 flask

c. The N2 molecules collide more frequently with the walls of the flask than do the Ar atoms. TRUE

The collision probability of N2 is higher because there are more molecules presents

Answer:

0.616 moles of Fe₂(CO₃)₃ are produced when 200 g of FeCl₃ react

b. 1.

Explanation:

The balanced reaction is:

First we convert 200 grams of FeCl₃ into moles, using its molar mass:

Then we convert 1.23 moles of FeCl₃ into moles of Fe₂(CO₃)₃, using the stoichiometric coefficients of the balanced reaction:

The closest answer would be option b. 1.

Explanation:

[tex]FeCl₃ + (NH₄)₂CO₃ → NH₄Cl + Fe₂(CO₃)₃[/tex]

first balance the chemical equation

[tex]2FeCl₃ + 3(NH₄)₂CO₃ → 6NH₄Cl + Fe₂(CO₃)₃[/tex]

2 mole. 3 mole. 6mole. 1mole

2*162g of FeCl₃ produce 236 g of Fe₂(CO₃)₃

200g of of FeCl₃

produce 236/(2*162)*20=145.68 g of Fe₂(CO₃)₃

1 mole of Fe₂(CO₃)₃=236g

145.68g of Fe₂(CO₃)=1/236*145.68=}0.61mole

closest answer is b 1

b.1mole(s) of iron (III) carbonate [Fe2CO3)3] is/are produced in the balanced equation

Peptide is the name of the molecule formed when two amino acids join together. Therefore, the correct option is option A.

Short strands of amino acids connected by peptide bonds are called peptidides. A polypeptide is a peptide chain that is longer, continuous, and unbranched. Proteins are polypeptides with a molecular weight of 10,000 Dalton or higher. Oligopeptides, which comprise dipeptides, tripeptides, and tetrapeptides, are chains of fewer than twenty amino acids.

Peptides, along with nucleic acids, oligosaccharides, carbohydrates, and others, belong to the vast chemical families of biological polymers or oligomers. Proteins are made up of one or even more polypeptides structured in a biologically useful manner. They are frequently coupled to other proteins, other macromolecules like DNA or RNA, or ligands like coenzymes and cofactors. Peptide is the name of the molecule formed when two amino acids join together.

Therefore, the correct option is option A.

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Answer:

B. Cu + AgNO3 → CuNO3 + Ag

C. 2NaBr + Cl2 → 2NaCl + Br2

D. F2 + 2NaBr → 2NaF + Br2

Explanation:

There are several types of reactions in chemistry, of which one of them is the SINGLE DISPLACEMENT REACTION. Single displacement reaction is that reaction in which only one element in a compound is displaced/replaced by another element.

The following reactions given in this question are examples of single displacement reactions;

- Cu + AgNO3 → CuNO3 + Ag

- 2NaBr + Cl2 → 2NaCl + Br2

- F2 + 2NaBr → 2NaF + Br2

* In the first reaction, silver (Ag) is displaced by copper (Cu)

* In the second reaction, bromine (Br) is displaced by chlorine (Cl)

* In the third reaction, bromine (Br) is displaced by fluorine (F)

The single replacement reaction are;

A single displacement reaction is one in which one of the reactants replaces another. A typical example is the reaction; A + BC ---> AB + C.

Having this in mind, we can see that the reactions that correspond to a single replacement reaction are;

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Answer:

11

∘

C

Explanation:

As far as solving this problem goes, it is very important that you do not forget to account for the phase change underwent by the solid water at

0

∘

C

to liquid at

0

∘

C

.

The heat needed to melt the solid at its melting point will come from the warmer water sample. This means that you have

q

1

+

q

2

=

−

q

3

(

1

)

, where

q

1

- the heat absorbed by the solid at

0

∘

C

q

2

- the heat absorbed by the liquid at

0

∘

C

q

3

- the heat lost by the warmer water sample

The two equations that you will use are

q

=

m

⋅

c

⋅

Δ

T

, where

q

- heat absorbed/lost

m

- the mass of the sample

c

- the specific heat of water, equal to

4.18

J

g

∘

C

Δ

T

- the change in temperature, defined as final temperature minus initial temperature

and

q

=

n

⋅

Δ

H

fus

, where

q

- heat absorbed

n

- the number of moles of water

Δ

H

fus

- the molar heat of fusion of water, equal to

6.01 kJ/mol

Use water's molar mass to find how many moles of water you have in the

100.0-g

sample

100.0

g

⋅

1 mole H

2

O

18.015

g

=

5.551 moles H

2

O

So, how much heat is needed to allow the sample to go from solid at

0

∘

C

to liquid at

0

∘

C

?

q

1

=

5.551

moles

⋅

6.01

kJ

mole

=

33.36 kJ

This means that equation

(

1

)

becomes

33.36 kJ

+

q

2

=

−

q

3

The minus sign for

q

3

is used because heat lost carries a negative sign.

So, if

T

f

is the final temperature of the water, you can say that

33.36 kJ

+

m

sample

⋅

c

⋅

Δ

T

sample

=

−

m

water

⋅

c

⋅

Δ

T

water

More specifically, you have

33.36 kJ

+

100.0

g

⋅

4.18

J

g

∘

C

⋅

(

T

f

−

0

)

∘

C

=

−

650

g

⋅

4.18

J

g

∘

C

⋅

(

T

f

−

25

)

∘

C

33.36 kJ

+

418 J

⋅

(

T

f

−

0

)

=

−

2717 J

⋅

(

T

f

−

25

)

Convert the joules to kilojoules to get

33.36

kJ

+

0.418

kJ

⋅

T

f

=

−

2.717

kJ

⋅

(

T

f

−

25

)

This is equivalent to

0.418

⋅

T

f

+

2.717

⋅

T

f

=

67.925

−

33.36

T

f

=

34.565

0.418

+

2.717

=

11.026

∘

C

Rounded to two sig figs, the number of sig figs you have for the mass of warmer water, the answer will be

T

f

=

11

∘

C

Explanation:

Answer:

Mole = number of molecules divided by the avogadro's constant.

Molar mass of NaCI =23 + 35.5 =58.5g/mol

Mass= moles multipled by molar mass of NaCI

M

Answer:1.12 g

Explanation:Molar mass of compound ​FeSO4(NH4)2SO4.6H2O = 392.14 g mol-1

Number of moles of compound in 7.84g sample = 7.84 g/ 392.14 g mol-1

                                                                       = 0.02 mole

1 mole of sample contain 1 mole of Fe

So, 0.02 mole of sample would contain 0.02 moles of Fe.

Mass of Fe equivalent to 0.02 mole = 0.02 mol x molar mass of Fe

                                                    = 0.02 mol x 55.84 g mol-1

                                                   = 1.12 g

Answer:

1. Washing dishes and cooking

2. Water is used as a solvent in the manufacture of beverages and it is also largely used in agriculture.

3. Water conservation is the action of using water wisely and not wasting it.

4. i) Wash dishes in a tub of water instead of under a running tap.

ii) Use a pail of water to wash the car instead of spraying water from a hose.

iii) Make sure that there are no leaking or broken taps and pipes.

Answer:

Washing dishes and cooking

2. Water is used as a solvent in the manufacture of beverages and it is also largely used in agriculture.

3. Water conservation is the action of using water wisely and not wasting it.

4. i) Wash dishes in a tub of water instead of under a running tap.

ii) Use a pail of water to wash the car instead of spraying water from a hose.

iii) Make sure that there are no leaking or broken taps and pipes.

Explanation:

Answer:

A glacier is a large mass of snow and ice that has accumulated over many years and is present year-round. In the United States, glaciers can be found in the Rocky Mountains, the Sierra Nevada, the Cascades, and throughout Alaska. A glacier flows naturally like a river, only much more slowly. At higher elevations, glaciers accumulate snow, which eventually becomes compressed into ice. At lower elevations, the “river” of ice naturally loses mass because of melting and ice breaking off and floating away (iceberg calving) if the glacier ends in a lake or the ocean. When melting and calving are exactly balanced by new snow accumulation, a glacier is in equilibrium and its mass will neither increase nor decrease.

In many areas, glaciers provide communities and ecosystems with a reliable source of streamflow and drinking water, particularly in times of extended drought and late in the summer, when seasonal snowpack has melted away. Freshwater runoff from glaciers also influences ocean ecosystems. Glaciers are important as an indicator of climate change because physical changes in glaciers whether they are growing or shrinking, advancing or receding provide visible evidence of changes in temperature and precipitation. If glaciers lose more ice than they can accumulate through new snowfall, they ultimately add more water to the oceans, leading to a rise in sea level (see the Sea Level indicator). The same kinds of changes occur on a much larger scale within the giant ice sheets that cover Greenland and Antarctica, potentially leading to even bigger implications for sea level. Small glaciers tend to respond more quickly to climate change than the giant ice sheets. Altogether, the world’s small glaciers are adding roughly the same amount of water to the oceans per year as the ice sheets of Greenland and Antarctica combined. During the last two decades, they added more water overall to the oceans than the ice sheets did.

Explanation:

please give this answer as brainliest answer

Because they offer a variety of essential functions, including as controlling river flows and water supply, safeguarding coastal areas from floods, and preserving biodiversity, glaciers are a crucial component of human survival.

First, many people throughout the world rely heavily on glaciers as a supply of freshwater. When glaciers melt, they release water that has been stored and is subsequently utilised for agriculture, drinking water, and other things.

In dry areas with limited access to other freshwater sources, this water is very crucial. As a natural reservoir, glaciers may also hold a lot of water during the winter and release it gradually throughout the summer. This helps to control river flows and avoid flooding.

Second, glaciers contribute significantly to the global climate.system of climate. Large volumes of carbon dioxide and other greenhouse gases are released as glaciers melt, which can contribute to global warming. Glaciers may also reflect sunlight, which aids in cooling the surroundings around them.

High-altitude places, where glaciers can help regulate temperatures and avert catastrophic weather occurrences, are particularly crucial for this cooling impact. Last but not least, glaciers are crucial for the preservation of biodiversity. Numerous types of plants, animals, and microorganisms find a special niche in glaciers. These species may be disrupted by glacier melting, which might result in the extinction of entire ecosystems. The environment and the communities who rely on it may be significantly impacted by this.

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Answer:

XeF4                  True

[PdCl4]2−           True

naphthalene      True

Furan                  False

C4H4O               False  

Explanation:

From the given information:

Only XeF4;  [PdCl4]2−;  naphthalene are true. This is because their molecules contain -nC₂ axis which is perpendicular to the Cn axis. The image attached below shows the structural formula of each compound, there below, we can see that Furan only possesses one C₂ axis but not -nC₂ ⊥ C₂.