what js the percent yield of lithium hydroxide from a reaction of 7.40 g of lithium with 10.2 g of water? the actual yield was measured to be12.1 g

Answer:

Lithium chloride (LiCl), carbon dioxide, and water

Explanation:

Li₂CO₃ + HCl ⇒ LiCl + CO₂ + H₂O

When lithium carbonate reacts with hydrochloric acid, lithium chloride, water, and bubbles of carbon dioxide gas are given off. This is the result of a double displacement reaction followed by a decomposition reaction.

Hope that helps.

Answer:

After 47.9 days, will remain 14.5mg of the isotope

Explanation:

The radioactive decay follows always first-order kinetics where its general law is:  

Ln[A] = -Kt + ln[A]₀

Where [A] is actual concentration of the atom, k is rate constant, t is time and [A]₀ is initial concentration.

We can find rate constant from half-life as follows:

[tex]t_{1/2} = \frac{ln2}{K}[/tex]

K = ln 2 / 27.7 days

K = 0.025 days⁻¹

Replacing, initial amount of isotope is 48.0mg = [A]₀ , K is 0.025 days⁻¹ and t = 47.9 days:

Ln[A] = -Kt + ln[A]₀

Ln[A] = -0.025 days⁻¹*47.9 days + ln (48.0mg)

ln [A] = 2.6726

[A] = e^ (2.6726)

[A] = 14.5mg

Answer : HBr polar

please add me to brainalist

Answer:

H₂CO₃   H₂O  ⇄  HCO₃⁻  +  H₃O⁺          Ka1

HCO₃⁻  +  H₂O  ⇄  CO₃⁻²  +  H₃O⁺        Ka2

CO₃⁻²  +  H₂O  ⇄  HCO₃⁻   +  OH⁻       Kb1

HCO₃⁻  +  H₂O  ⇄   H₂CO₃  +  OH⁻     Kb2

Explanation:

Formula for carbonic acid is: H₂CO₃

It is a dyprotic acid, because it can release two protons. We can also mention that is a weak one. The equilibrums are:

H₂CO₃   H₂O  ⇄  HCO₃⁻  +  H₃O⁺          Ka1

HCO₃⁻  +  H₂O  ⇄  CO₃⁻²  +  H₃O⁺        Ka2

When the conjugate strong bases, carbonate and bicarbonate take a proton from water, the reactions are:

CO₃⁻²  +  H₂O  ⇄  HCO₃⁻   +  OH⁻       Kb1

HCO₃⁻  +  H₂O  ⇄   H₂CO₃  +  OH⁻     Kb2

Notice, that bicarbonate anion can release or take a proton to/from water. This is called amphoteric,

Answer:

0.05 mole of Br2.

Explanation:

We'll begin by writing the balanced equation for the reaction. This is given below:

C2H4 + Br2 —› C2H4Br2

From the balanced equation above,

1 mole of C2H4 reacted with 1 mole of Br2 to produce 1 mole of C2H4 Br2.

Finally, we shall determine the number of moles bromine that will react with 0.05 mole of C2H2.

The number of mole of Br2 needed for the reaction can be obtained as follow:

From the balanced equation above,

1 mole of C2H4 reacted with 1 mole of Br2.

Therefore, 0.05 mole of C2H4 will also react with 0.05 mole of Br2.

Therefore, 0.05 mole of Br2 is needed for the reaction.

Answer:

To prepare vegetables for finishing by grilling, sautéing, pan frying, deep frying, or stewing, you should parboil them to cook them to partial doneness.

Answer:

[tex]M=0.684M[/tex]

Explanation:

Hello,

In this case, considering that the solution is formed by NaCl as the solute and water as the solvent, we can compute the molarity as shown below:

[tex]M=\frac{mol_{solute}}{V_{solution}}[/tex]

Whereas the volume of the solution must be in liters. In such a way, since the addition of sodium chloride does not significantly changes the volume of the solution we can say it remains in 100 mL (0.100 L) and the moles of sodium chloride are computed by using its molar mass (58.45 g/mol):

[tex]mol_{solute}=4g*\frac{1mol}{58.45g} =0.0684mol[/tex]

Therefore, the molarity is:

[tex]M=\frac{0.0684mol}{0.100L} \\\\M=0.684\frac{mol}{L}=0.684M[/tex]

Regards.

Answer:

a) NH3/NH4Cl (pKa = 9.25)

b) [tex]\frac{[Base]}{[Acid]} =0.708[/tex]

c)

Explanation:

Hello,

a) In this case, for a buffering capacity, if we want to select the best buffer, we should ensure that the buffer's pKa approaches the desired pH, therefore, since the buffer NH3/NH4Cl has a pKa of 9.25 that is very close to the desired pH of 9.10, we can pick it as the best choice.

b) In this case, we use the Henderson-Hasselbach equation in order to compute the molar ratio:

[tex]pH=pKa+log(\frac{[Base]}{[Acid]} )\\\\log(\frac{[Base]}{[Acid]} )=9.10-9.25=-0.15\\\\\frac{[Base]}{[Acid]} =10^{-0.15}\\\\\frac{[Base]}{[Acid]} =0.708[/tex]

c) Finally, for the ratio of masses, we use the molar mass of both ammonia as the base (17 g/mol) and ammonium chloride as the acid (53.45 g/mol) to compute it, assuming 1.00 L as the volume of the solution:

[tex]\frac{m_{Base}}{m_{Acid}} =0.708\frac{molBase}{molAcid}*\frac{17gBase}{1molBase} *\frac{1molAcid}{53.45gAcid}\\ \\\frac{m_{Base}}{m_{Acid}} =0.225[/tex]

Regards.

The best choice to create a buffer with pH 9.10 is NH₃/NH₄Cl (pKa=9.25), ratio of molarities and masses for NH₃/NH₄Cl are 0.708 & 0.225 respectively.

pH of buffer solution will be calculated by using the Henderson Hasselbalch equation as:

pH = pKa + log([base]/[acid])

        log([NH₃]/[NH₄Cl]) = 9.10 - 9.25 =

        log([NH₃]/[NH₄Cl]) = -0.15

       [NH₃]/[NH₄Cl] = [tex]10^{-0.15}[/tex] = 0.708

        M = n/V, where

        M = molarity

        V = volume = 1L

        n = moles = W(mass) / M(molar mass)

        Mass(NH₃)/Mass(NH₄Cl) = 0.708 {(mol of NH₃×17g of NH₃NH₃) /          

                                                              (mol of NH₄Cl×53.45g of NH₄Cl)

       Mass(NH₃)/Mass(NH₄Cl) = 0.225

Hence required values are calculated above.

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Answer:

C10H22

Explanation:

Graphite is known as an allotrope of carbon. Its characteristics include being black and slippery and as used as lubricants.

Gold (Au) is an element on the periodic table with atomic number 79 and a mass number 197 which exists as a metal due to its hydrogen bonds.

C10H22 which is also known as decane belongs to the Alkane family.The General forces of attraction between the alkane family are weak but in the case of decade there is Van der waal force which makes Decane C10H22 a Molecular Solid.

Answer:

[OH-] = 1.0 x 10-10 M

Explanation:

The acidity of a solution can be determined directly from the concentration of the hydrogen ions and indirectly from the concentrations of the hydroxide ions.

Generally, for a neutral solution we have;

[H3O+] = [OH-] = 1.0 x 10-7 M

For an acidic solution;

[H3O+] > 1.0 x 10-7 M

[OH-] < 1.0 x 10-7 M

Comparing the options the correct option is;

[OH-] = 1.0 x 10-10 M

Answer:

310 mL

Explanation:

Step 1: Given data

Step 2: Calculate the initial volume

We have a concentrated HBr solution and we want to prepare a diluted one. We can do so using the dilution rule.

C₁ × V₁ = C₂ × V₂

V₁ = C₂ × V₂ / C₁

V₁ = 0.400 M × 5.50 L / 7.10 M

V₁ = 0.310 L = 310 mL

Answer:

Explanation:

MnO₂(s) + 4 HCl(aq)  = MnCl₂(aq) + 2 H₂O(l) + Cl₂

87 g                                                                     22.4 x 10³ mL

volume of given chlorine gas at NTP or at 760 Torr and 273 K

=  175 x ( 273 + 25 ) x 715 / (273 x 760 )

= 179.71 mL

22.4 x 10³ mL of chlorine requires 87 g of MnO₂

179.4 mL of chlorine will require    87 x 179.4 / 22.4 x 10³ g

= 696.77 x 10⁻³ g

= 696.77 mg .

Answer:

The rms speed of its molecules becomes. (T) has become four times. Therefore, v_(rms) will become two times,...

Answer:

Bronsted lowry base = Proton acceptor = H2O

Bronsted lowry acid = Proton donor = HF-

Explanation:

The equation is given as;

HF-(aq) + H2O(l) --> F-(aq) + H3O(aq)

A bronsted lowry base is any specie that can accept hydrogen ion (proton) from another molecule.

Basically a bronsted lowry base is  a proton acceptor while a bronsted lowry acid is a proton donor.

In the reaction above, upon comparing both the reactants and products;

Bronsted lowry base = Proton acceptor = H2O

Bronsted lowry acid = Proton donor = HF-

Answer:

(1) -12 Kcal/mol

Explanation:

Our answer options for this question are:

(1) -12 Kcal/mol

(2) -13 Kcal/mol

(3) -15 Kcal/mol

(4) -16 Kcal/mol

With this in mind, we can start with the chemical reaction (Figure 1). In this reaction, two bonds are broken, a C-H and a Br-Br. Additionally, a C-Br and a H-Br are formed.

If we want to calculate the enthalpy value, we can use the equation:

ΔH=ΔHbonds broken-ΔHbonds formed

If we use the energy values reported, its possible to calculate the energy for each set of bonds:

ΔHbonds broken

C-H = 94.5 Kcal/mol

Br-Br = 51.5 Kcal/mol

Therefore:

105 Kcal/mol + 53.5 Kcal/mol = 146 Kcal/mol

ΔHbonds formed

C-Br = 70.5 Kcal/mol

H-Br = 87.5 Kcal/mol

Therefore:

70.5 Kcal/mol + 87.5 Kcal/mol = 158 Kcal/mol

ΔH of reaction

ΔH=ΔHbonds broken-ΔHbonds formed=(146-158) Kcal/mol = -12 Kcal/mol

I hope it helps!

Answer:

Atomic mass = 127.198 amu

Explanation:

The average atomic mass is obtained by summing the masses of the isotopes each multiplied by its abundance.

Atomic mass = (97.62 * 0.0825) + (109.3 * 0.2671) + (138.3 * 0.6504)

Atomic mass = 8.05365 +  29.19403 + 89.95032

Atomic mass = 127.198 amu

Explanation:

Entropy refers to the degree of disorderliness of a system.

a. A snowman melts on a spring day.

Entropy is increasing because there is a change in state of matter from solid to liquid. Liquid particles have more freedom f movement compared to solids.

b. A document goes through a paper shredder.

Entropy increases because random, disorganized bits of paper are left.

c. A water bottle cools down in a refrigerator.

Entropy  decreases because temperature is directly proportional to entropy.

d. Silver tarnishes

Entropy increases because random bits of the sliver particles are formed.

e. Dissolved sugar precipitates out of water to form rock candy.

Entropy decreases because the random dissolved sugar precipitates are ordered into a rock candy.

Answer: So other scientist can replicate the experiment and see if they get the same results in other words, test reliability.

Explanation:

Answer:

The correct option is C.

Note the full question and structure of the moleculesis found in the attachment below.

Explanation:

Triglycerides or triacylglycerols are non-polar, hydrophobic lipid molecules composed of three fatty acids linked by ester bonds to a molecule of glycerol.

The fatty acids linked to the glycerol molecule are denoted by R and may be of the same kind or different. when the R group is the same, the R is attached in all the three positions for ester bonding in the glycerol molecule but when they are different are denoted by R, R' and R'' respectively.

During the hydrolysis of triglycerides, the three fatty acids molecules are obtained as well as a glycerol molecule.

From the question, when 1 mole of the triglyceride is hydrolysed, 2 moles of RCOOH, 1 mole of R'COOH and 1 mole of glycerol is obtained. The triglyceride must then be composed of two fatty acids which are the same denoted by R, and a different fatty acid molecule denoted by R'.

The correct option therefore, is C

Answer:

27°C or 300K

Explanation

We were told that the pressureof the system decreased by 10 times implies that P2= P1/10

Where P2=final pressure

P1= initial pressure

Wew were also told that the volume of the system increased by 5 times this implies that V2= 5×V1

Where T2= final temperature =-123C= 273+(-123C)=150K

T1= initial temperature

But from gas law

PV=nRT

As n and R are constant

P1V1/T1 = P2V2/T2

T1= P1V1T2/P2V2

T1=2×T2

T1=2×150

T1=300K

=300-273

=27°C

the initial temperature (°C) of a system is 27°C

Answer:

Depends on the reaction.

Explanation:

Hello,

In this case, the answer is depends on the reaction since the ratios between the rates of both consumption and formation depend upon the stoichiometric coefficients in the chemical reaction. For instance, for the reaction:

A -> 2B

The relationship is:

[tex]\frac{1}{-1}r_A =\frac{1}{2} r_B[/tex]

Therefore, we can see that the rate of consumption of A half the rate of formation of B, but is we consider the following chemical reaction:

2A -> B

The relationship is:

[tex]\frac{1}{-2}r_A =\frac{1}{1} r_B[/tex]

Therefore we can see that the rate of consumption of A doubles the rate of consumption of B.

Best regards.

Answer:

[tex][H^+]=0.000123M[/tex]

[tex]pH=3.91[/tex]

Explanation:

Hello,

In this case, dissociation reaction for acetic acid is:

[tex]CH_3COOH\rightleftharpoons CH_3COO^-+H^+[/tex]

For which the equilibrium expression is:

[tex]Ka=\frac{[CH_3COO^-][H^+]}{[CH_3COOH]}[/tex]

Which in terms of the reaction extent [tex]x[/tex] could be written as:

[tex]1.74x10^{-5}=\frac{x*x}{[CH_3COOH]_0-x}=\frac{x*x}{0.0010M-x}[/tex]

Thus, solving by using a solver or quadratic equation we obtain:

[tex]x_1=0.000123M\\\\x_2=-0.000141M[/tex]

And clearly the result is 0.000123M, which also equals the concentration of hydronium ion in solution:

[tex][H^+]=0.000123M[/tex]

Now, the pH is computed as follows:

[tex]pH=-log([H^+])=-log(0.000123)\\\\pH=3.91[/tex]

Best regards.

Answer:

b. carbon diamond turning to carbon graphite at normal pressure.

Explanation:

Graphite is the stable form of the carbon element under normal ambient pressure.  The process of conversion of carbon diamond to carbon graphite is a spontaneous process under typical ambient conditions, since diamonds are said to be thermodynamically unstable but kinetically stable under ambient conditions, and the process of conversion can take place without a continuous input of energy from an external source.

Answer:

NSAIDs are steroidal anti-inflammatories, their action is on the phospholipase A2 enzyme, this enzyme is responsible for breaking down the phospholipids of the membrane to trigger an inflammatory response. This is how steroidal anti-inflammatory drugs inhibit ALL inflammatory pathways (not like NSAIDs that they only inhibit the COX pathway).

These corticosteroid drugs cannot exceed the systemic mineralocorticoid value 1 in the body, since this corticosteroid hormone is also released by the adrenal cortex.

The NSAIDs generate: sporadic peaks in blood glucose, hypertension, fluid retention, increase in body fat mass, possible suppression of the adrenal cortex over time, inhibiting endogenous synthesis of corticosteroids.

On the other hand, naproxen and ibuprofen are NSAIDs, that is, non-steroidal anti-inflammatory drugs that do not influence both routes of inflammation, but only COX, this enzyme is abbreviated as COX but is called cyclooxygenase, and is responsible for a single route of inflammation.

NSAIDs such as naproxen and ibuprofen can cause gastric disorders such as ulcers or gastritis if they are consumed in a very repetitive manner.

In addition, both drugs are anti-inflammatory, analgesic and antipyretic. Although its two main functions are the first two, it was shown to have an effect in lowering body temperature.

That they are anti-inflammatory means that they inhibit the path of inflammation and analgesics the path of pain.

Explanation:

Both types of drugs generate the same effect but by different mechanisms.

Some are steroids and others are not, although steroids are considered to have a greater risk of benefit that is why they are administered against more systematically compromised instances such as anaphylactic shock.

NSAIDs such as naproxen and ibuprofen are the most prescribed today, since they have few risks and very good benefits, meaning that their adverse effects are not lethal or highly relevant and have a good effect on symptoms.

Both must be administered with care when treating a diabetic patient since corticosteroids generate glycemic peaks or increase in blood glucose, and NSAIDs compete for plasma protein with oral hypoglycemic agents, thus generating that these are in higher free concentrations. high diffusing better through the tissues and increases the potency of the adverse effects of these.

Answer:

im pretty sure its the anode

Explanation:

To solve such, we must know the concept of electrolysis reaction. The correct option is option D among all given options. At anode electrode oxygen forms.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

Electrolysis is the process of passing an electric current through a material to cause a chemical change. A chemical change occurs when a material loses or acquires the electron. To refine aluminum from its ore, aluminum oxide is electrolyzed to form aluminum and oxygen. At anode electrode oxygen forms.

Therefore, the correct option is option D among all given options. At anode electrode oxygen forms.

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Answer:

Boiling

Explanation:

When a liquid is heated, the vapor pressure rises steadily. When water attains a temperature of 100°C or 212°F its vapor pressure is now equal to the atmospheric pressure at sea level, this is what we mean by boiling.

When this occurs, water continues to evaporate untill the vapor pressure inside the bubbles becomes high enough to stop water bubbles from collapsing again from the pressure of the water around it so the bubbles rise and break the surface.

Answer:

The temperature at which the vapor pressure would be 0.350 atm is 201.37°C

Explanation:

The relationship between variables in equilibrium between phases of one component system e.g liquid and vapor, solid and vapor , solid and liquid can be obtained from a thermodynamic relationship called Clapeyron equation.

Clausius- Clapeyron Equation can be put in a more convenient form applicable to vaporization and sublimation equilibria in which one of the two phases is gaseous.

The equation for Clausius- Clapeyron Equation can be expressed as:

[tex]\mathtt{In \dfrac{P_2}{P_1}= \dfrac{\Delta \ H _{vap}}{R} \begin {pmatrix} \dfrac{T_2 -T_1}{T_2 \ T_1} \end {pmatrix} }[/tex]

where ;

[tex]P_1[/tex] is the vapor pressure at temperature 1

[tex]P_ 2[/tex] is the vapor pressure  at temperature 2

∆Hvap = enthalpy of vaporization

R = universal gas constant

Given that:

[tex]P_1[/tex] = 1 atm

[tex]P_ 2[/tex]  = 0.350 atm

∆Hvap = 28.5 kJ/mol = 28.5 × 10³ J/mol

[tex]T_1[/tex] = 282 °C  = (282 + 273) K = 555 K

R = 8.314 J/mol/k

Substituting the above values  into the Clausius - Clapeyron equation, we have:

[tex]\mathtt{In \dfrac{P_2}{P_1}= \dfrac{\Delta \ H _{vap}}{R} \begin {pmatrix} \dfrac{T_2 -T_1}{T_2 \ T_1} \end {pmatrix} }[/tex]

[tex]\mathtt{In \begin {pmatrix} \dfrac{0.350}{1} \end {pmatrix} } = \dfrac{28.5 \times 10^3 }{ 8.314 } \begin {pmatrix} \dfrac{T_2 - 555}{555T_2} \end {pmatrix} }[/tex]

[tex]\mathtt{In \begin {pmatrix} \dfrac{0.350}{1} \end {pmatrix} } = \dfrac{28.5 \times 10^3 }{ 8.314 } \begin {pmatrix} \dfrac{1}{555}- \dfrac{1}{T_2} \end {pmatrix} }[/tex]

[tex]- 1.0498= 3427.953 \begin {pmatrix} \dfrac{1}{555}- \dfrac{1}{T_2} \end {pmatrix} }[/tex]

[tex]\dfrac{- 1.0498}{3427.953}= \begin {pmatrix} \dfrac{1}{555}- \dfrac{1}{T_2} \end {pmatrix} }[/tex]

[tex]- 3.06246906 \times 10^{-4}= \begin {pmatrix} \dfrac{1}{555}- \dfrac{1}{T_2} \end {pmatrix} }[/tex]

[tex]\dfrac{1}{T_2} = \begin {pmatrix} \dfrac{1}{555}+ (3.06246906 \times 10^{-4} ) \end {pmatrix} }[/tex]

[tex]\dfrac{1}{T_2} = 0.002108048708[/tex]

[tex]T_2 = \dfrac{1}{0.002108048708}[/tex]

[tex]\mathbf{T_2 }[/tex] =  474.37 K

To °C ; we have [tex]\mathbf{T_2 }[/tex] =   (474.37 - 273)°C

[tex]\mathbf{T_2 }[/tex] =  201.37 °C

Thus, the temperature at which the vapor pressure would be 0.350 atm is 201.37 °C

The temperature of the liquid at the given vapor pressure is 201.5 ⁰C.

The given parameters;

The temperature of the liquid will be determined by applying Clausius- Clapeyron Equation;

[tex]ln(\frac{P_2}{P_1} ) = \frac{\Delta H}{R} (\frac{T_2 -T_1}{T_1T_2} )[/tex]

where;

[tex]ln(\frac{P_2}{P_1} ) = \frac{\Delta H}{R} (\frac{T_2 -T_1}{T_1T_2} )\\\\ln(\frac{0.35}{1} ) = \frac{28.5 \times 10^3}{8.314} (\frac{T_2 - 555}{555T_2} )\\\\-1.049 = 6.176- \frac{3427.95}{T_2} \\\\\frac{3427.95}{T_2} = 6.176 + 1.049\\\\\frac{3427.95}{T_2} = 7.225\\\\T_2 = \frac{3427.95}{7.225} \\\\T_2 = 474.5 \ K\\\\T_2 = 474.5 - 273 = 201.5 \ ^0C[/tex]

Thus, the temperature of the liquid at the given vapor pressure is 201.5 ⁰C.

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Answer:

The salt breaks into positive chlorine ions and negative sodium icons

Explanation:

The question requested for the wrong option in the list. If we look at the option selected, we will notice that sodium ions are positively charged ions since sodium is a metal. Metals produce cations (positive ions) because they loose electrons. Therefore, a sodium ion can never be negatively charged.

Similarly, chlorine is a highly electronegative nonmetal. It gains electrons in an ionic bond. Hence chlorine ions can not be positive.

Answer:

The empirical formulae for the compound is CH3.

Answer: It's the anode broski (B)

Explanation: I'm taking the Chem summer course too broski, this was the correct answer. Cheers broski