calculate the specific heat of copper if it takes 23 cal to heat a 5.0 g sample from 25 C to 75 C

Answer:

[tex]Q=1.04kJ[/tex]

Explanation:

Hello,

In this case, for latent heat (phase change) we need to consider the enthalpy associated with the involved process, here, melting or fusion; thus, the enthalpy of fusion of copper is 13.2 kJ/mol, therefore, the heat is computed as:

[tex]Q=m\Delta H_{fus}[/tex]

Nevertheless, since the given enthalpy is per mole of copper, we need to use its atomic mass to perform the correct calculation as follows:

[tex]Q=5.0g*\frac{1mol}{63.54}* 13.2\frac{kJ}{mol}\\ \\Q=1.04kJ[/tex]

Which is positive as it needs to be supplied to the system.

Best regards.

Answer:

(a). The solubility of [tex]BaCO_{3}[/tex] in pure water is [tex]4.4\times10^{-5}\ M[/tex]

(b). The solubility of [tex]BaCO_{3}[/tex] in solution is [tex]6.92\times10^{-9}\ M[/tex]

Explanation:

Given that,

(a). The solubility of [tex]BaCO_{3}[/tex] in pure water

(b). The solubility of [tex]BaCO_{3}[/tex] in a solution

Solubility of [tex]CO_{3}^{-2}[/tex] is 0.289 M

We know that,

The solubility product constant  of  [tex]BaCO_{3}[/tex] is [tex]2\times10^{-9}[/tex]

Let the solubility of [tex]BaCO_{3}[/tex] is s.

We need to calculate the solubility of [tex]BaCO_{3}[/tex] in pure water

Using formula of solubility

[tex]ksp=s\times s[/tex]

[tex]ksp=s^2[/tex]

[tex]s=\sqrt{ksp}[/tex]

Put the value into the formula

[tex]s=\sqrt{2\times10^{-9}}[/tex]

[tex]s=4.4\times10^{-5}\ M[/tex]

(b). We need to calculate the solubility of [tex]BaCO_{3}[/tex] in solution

Using formula of solubility

[tex]ksp=s\times s[/tex]

Put the value into the formula

[tex]2\times10^{-9}=s\times 0.289[/tex]

[tex]s=\dfrac{2\times10^{-9}}{0.289}[/tex]

[tex]s=6.92\times10^{-9}\ M[/tex]

Hence, (a). The solubility of [tex]BaCO_{3}[/tex] in pure water is [tex]4.4\times10^{-5}\ M[/tex]

(b). The solubility of [tex]BaCO_{3}[/tex] in solution is [tex]6.92\times10^{-9}\ M[/tex]

Answer:

The correct answer is  1.977 % m/v ≅ 2% m/v

Explanation:

We have:

0.617 M = 0.617 moles methanol/ 1 L solution

We need:

%m/v= grams of methanol/100 mL solution

So, first we convert the moles of methanol to grams by using the MM (32.04 g/mol). Then, we multiply by 0,1 to convert the volume in liters to 100 mL by using the ratio: 100 mL= 0.1 L:

0.617 mol / 1 L x 32.04 g/mol 0.1 L/100 mL= 1.977 g/100 mL= %m/v

The concentration in [tex]\%_{m/v}[/tex] of a 0.617 M aqueous solution of methanol is 1.98%.

To find the [tex]%_{m/v}[/tex] concentration of methanol we need to use the following equation:

[tex] \%_{m/v} = \frac{m_{s}}{V_{sol}} \times 100 [/tex]   (1)

Where:

[tex] m_{s}[/tex]: is the mass of methanol in grams

[tex] V_{sol} [/tex]: is the volume of the solution in milliliters

The molar concentration of methanol is:

[tex] C = 0.617 M = 0.617 \:\frac{mol}{L} [/tex]

From this concentration, we can find the mass of methanol

[tex] m = n*MM [/tex]   (2)

Where:

n: is the number of moles = C*V

MM: is the molar mass = 32.04 g/mol

Then, the mass of methanol is (eq 2):

[tex] m = n*MM = C*V*MM = 0.617 mol/L*1 L*32.04 g/mol = 19.77 g [/tex]

Knowing that 1 L = 1000 mL, the [tex]%_{m/v}[/tex] concentration is (eq 1):

[tex] \%_{m/v} = \frac{m_{s}}{V_{sol}} \times 100 = \frac{19.77 g}{1000 mL} \times 100 = 1.98 \% [/tex]

Therefore, the concentration in [tex]\%_{m/v}[/tex] is 1.98%.

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Answer:

b. Q

Explanation:

Equilibrium constant K is a measure of the ratio of the equilibrium concentration of the products of a reaction to the equilibrium concentration of the reactants with each concentration raised to the power corresponding to the coefficient in the balanced equation of the reaction.

On the other hand , the [tex]E^\theta_{cell}[/tex] is the standard electrode potential of the right-hand electrode minus the standard electrode potential of the left hand electrode, Thus, [tex]E^\theta_{cell}[/tex] will be zero if concentration cell in the two electrodes appears to be the same.

The Nernst equation correlates  the cell E.M.F to a standard value E and the activities of the species that takes places in the cell reaction. Thus in a concentration cell, the reaction is driven by Q

Answer:

Carbons 1 and 3

Explanation:

We must remember that by definition alpha carbons are the carbon (or carbons) next to the carbon that contains the main group. In this case, the main group is the carbonyl group (C = O) in the middle of the molecule. In the acetone molecule, we have three carbons, the carbons neighboring the carbon of the carbonyl group (carbon two) will be the alpha carbons. (Red and blue carbons or carbons one and three)

See figure 1 for further explanations.

I hope it helps!

Answer:

Mass.

Explanation:

Hello,

In this case, we should remember that dimensions are useful to represent the quantity that a property has. For instance, when measuring mass, volume, density and temperature, the value that the property has at a specific condition must be accompanied with the corresponding unit. In such a way, since the measurement is given as 0.2002 grams, we can identify those grams accounts for mass.

Best regards.

Answer:

[tex]\%m/m=0.15\%[/tex]

Explanation:

Hello,

In this case, we are asked to compute the by mass percent representing the toxicity of ethylene glycol in the body mass. In such a way, since the by mass percent is computed as follows:

[tex]\%m/m=\frac{m_{solute}}{m_{solute}+m_{solvent}} *100\%[/tex]

Whereas the solute is the ethylene glycol in the body mass, we obtain:

[tex]\%m/m=\frac{1.5g}{1.5g+1000g} *100\%\\\\\%m/m=0.15\%[/tex]

Best regards.

The percentage of ethylene glycol that is fatal would be 0.15%.

The toxic quantity is 1.5 g of ethylene glycol for 1000 g of body mass.

The percentage toxic quantity in relation to the body mass can be calculated as:

Percentage = mass of toxic quantity/body mass x 100%

                    = 1.5/1000 x 100%

                       = 0.15 %

Thus, the fatal level of ethylene glycol is 0.15% of body mass.

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Answer:

See the answer below

Explanation:

The pH scale is important in science because it gives an indication of how acidic or basic a solution is. The scale ranges from 0 - 14 with 0 being the most acidic and 14 being the most basic while a pH of 7 is a neutral pH.

The pH scale is widely applicable in several scientific applications such as in medicine/health, agricultural processes, industrial processes, environmental monitoring, research and development, etc.

In medicine, the pH of the stomach is monitored in order to make some diagnosis. The normal pH of the human stomach ranges from 1.5 - 3.5 and a major deviation from this range can give an indication of wrong health.

In agriculture, the pH condition of the soil on which crops are grown is quite important. While some crops require slightly acidic soil, some will only do well in alkaline soil. Hence, the pH condition of the soil must be monitored to ensure the optimal yield of crops.

Several industrial processes require the monitoring of pH in order to ensure product's quality or monitor some important reactions. In food industries, for example, monitoring the pH of reactions is necessary in order to prevent contamination by pathogens or ensure a good organoleptic quality of the final product. It is also necessary to monitor the pH of industrial wastewaters in order to avoid polluting the environment.

Monitoring pH is also important for environmental monitoring, The pH of various water bodies or soil can give an indication of the level of pollution in the water or the soil.

The pH can be defined as the concentration of the hydrogen ions in the sample. The determination of pH helps in the designing of the study and investigating the reactions.

Some of the examples for the scientific application of pH has been:

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Answer:

Exothermic

Explanation:

A reaction is said to be exothermic when heat is evolved in the process. The evolution of heat implies that the energy of reactants is greater than that of the products, hence energy is given off when the products are formed.

If you dissolve sodium hydroxide in water, the vessel feels hot when touched. This signifies that energy is given off during the process. Hence the formation of an aqueous solution of sodium hydroxide is exothermic.

Answer:

a. the anode.

Explanation:

An anode is an electrode through which the conventional current enters into a polarized electrical device. This contrasts with a cathode, an electrode through which conventional current leaves an electrical device

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Answer: the cathode, by convention the components of the cathode are always listed last

Answer:

a. True

Explanation:

In this reaction, we will have a hydride transfer to the carbon of the carbonyl group, moving the electrons of the double bond towards the oxygen producing a negative charge. The double bond is then regenerated by removing the chlorine atom from the molecule, producing an aldehyde.

Then, another molecule the LiAlH4 transfers another hydride to the carbon of the carbonyl group, again producing a negative charge on the oxygen. Finally, the hydrogen is protonated producing a primary alcohol.

See figure 1

I hope it helps!

Answer:

The reaction is exothermic

Explanation:

If we look at this reaction system closely, we will discover that the energy of reactants is greater than that of the product. The excess energy possessed by the reactants must be given off at the end of the reaction.

Since ∆Hrxn = ∆Hproducts - ∆Hreactants and ∆Hreactants > ∆Hproducts hence ∆Hrxn is negative and the reaction is exothermic, hence the answer.

Answer:

B. cocamide DEA

C. folic acid

D. iron

G. lauryl glucoside

Answer:

correct option is (a)

The solution would be using this: C6H5COOH = H+ + C6H5COO Ka = 6.5 x 10^-5 = (H+)(C6H5COO-) over

(C6H5COOH)

Let X = moles per liter (H+) and also = moles per liter (C6H5COO-)

Ka = 6.5 x 10^-5 = (X)(X) over .350 molar = acid solution 6.5 x 10^-5 = X^2 over .350

X^2 = 6.5 x 10^-5 times .350 which = 2.275 x 10^-5

x = V2.275 x 10^-5

X = 1.5083 x 10^-5 moles per liter H+

pH = -log(H+) = -log 1.5083 x 10^-5 which

= 4.6215

The pH of a 0.350 M aqueous benzoic acid solution is 4.64. The correct option is a).

In chemistry, the pH scale is used to define the acidity or basicity of an aqueous solution. Historically, pH stood for "potential of hydrogen."

The solution would be using this: C₆H₅COOH = H+ + C₆H₅COO Ka = 6.5 x 10⁻⁵ = (H+)(C₆H₅COO-) over

(C₆H₅COOH)

Let X = moles per liter (H+) and also = moles per liter (C6H5COO-)

Ka = 6.5 x 10⁻⁵ = (X)(X) over .350 molar = acid solution 6.5 x 10⁻⁵= X² over .350

X² = 6.5 x 10⁻⁵ times .350 which = 2.275 x 10⁻⁵

x = V2.275 x 10⁻⁵

X = 1.5083 x 10⁻⁵ moles per liter H+

pH = -log(H+) = -log 1.5083 x 10⁻⁵  = 4.6215

Therefore, the pH is 4.6215. The correct option is a). round to 4.64.

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Answer:

Environmental science is also referred to as an interdisciplinary field because it incorporates information and ideas from multiple disciplines. Within the natural sciences, such fields as biology, chemistry, and geology are included in environmental science.

Explanation:

Environmental science is an interdisciplinary science because it integrates physics, biology, and geography  to the study of the environment, and the solution of environmental problems.

Environmental science is the field of science that studies the interactions of the physical, chemical, and biological components of the environment and the relationships .

Interdisciplinary science allows you to study according to your professional and academic abilities and goals .

Environmental science is an interdisciplinary science because it integrates physics, biology, and geography  to the study of the environment, and the solution of environmental problems.

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Answer:

Option a: positron emission.

Explanation:

In the transformation we have:

⁶⁷Ga  →  ⁶⁷Zn  

The reaction is:

[tex]^{67}_{Z}X \rightarrow ^{67}_{Z -1}Y[/tex]

For Ga to become Zn, the atom nucleus has to lose a proton, so in the given options, the reaction that involves the transformation of a proton is the option a, positron emission.

In a positron emission, a proton becomes into a neutron and a positron:

[tex]^{A}_{Z}X \rightarrow ^{A}_{Z-1}Y + ^{0}_{+1}e[/tex]

Therefore, the correct answer is option a: positron emission.

I hope it helps you!

Answer:

142.36 kg

Explanation:

volume of water in the lake = surface area x depth

= 18.5 x ( 1760 x 3 )² x 39 ft³

= 2.011 x 10¹⁰ ft³

= 2.011 x 10¹⁰ x 28.3168 liter .

= 56.945 x 10¹⁰ liter .

concentration of mercury = .25 x 10⁻⁶ g / liter

= 25 x 10⁻⁸ g / liter

= 25 x 10⁻¹¹ kg / liter

mass of mercury in the water of lake

= 25 x 10⁻¹¹ x 56.945 x 10¹⁰ kg

= 142.36 kg .

Answer:

4 g/mL

Explanation:

The density of a object can be found using the following formula.

[tex]d=\frac{m}{v}[/tex]

where m is the mass and v is the volume.

We know that the mass of the object is 24.0 grams and the volume is 6.0 milliliters.  

[tex]m= 24 g\\v=6 mL[/tex]

Substitute the values into the formula.

[tex]d= \frac{24g}{6mL}[/tex]

Divide 24 g by 6 mL.

[tex]d= 4 g/mL[/tex]

The density of the object is 4 grams per milliliter.

Answer:

4 g/mL

Explanation:

density = mass/volume

therefore, density = 24/6

ρ = 4 g/mL

Answer:

Acetone.

Explanation:

Hello,

In this case, we can distinguish between polar solvent and nonpolar solvent by the nature of the bonds present in the compound. Thus, since the bonds C-Cl, C-C, C-H and C-O are nonpolar, which are contained in the toluene, carbon tetrachloride, diethyl ether and hexane, they are discarded as polar.

Nevertheless, since the carbonyl group contained in the acetone is a polar because of the formed positive and negative charges, it is actually the polar solvent, acting as an exception. This is substantiated by the fact the acetone is soluble in water whereas the other substances not,

Regards.

Answer:

The correct answer is option b, that is, 2.1 M Na₃PO₄.

Explanation:

The solution with the largest concentration of ions will possess the highest conductivity.

a) 3.0 M NaCl

NaCl ⇔ Na⁺ + Cl⁻

Here the total number of ions is 2, therefore, the concentration of ions is 3.0 × 2 = 6.0 M

b) 2.1 M Na₃PO₄

Na₃PO₄ ⇔ 3 Na⁺ + PO₄³⁻

Here the total number of ions i 4. Therefore, the concentration of ions is

2.1 × 4 = 8.4 M.

c) 2.4 M CaCl₂

CaCl₂ ⇔ Ca²⁺ + 2Cl⁻

The total number of ions is 3. Therefore, the concentration of ions is

2.4 × 3 = 7.2 M

d) 3.2 M NH₄NO₃

NH₄NO₃ ⇔ NH₄⁺ + NO₃⁻

The total number of ions is 2. The concentration of ions will be,

3.2 × 2 = 6.4 M

Hence, the highest conductivity will be of 2.1 M Na₃PO₄.

Answer:

0.0338 moles of sodium bicarbonate are required to react with 0.9 mL 100% sulphuric acid solution

Explanation:

Equation of the reaction:

Na₂CO₃(aq) + H₂SO₄(aq) ---> Na₂SO₄(aq) + H₂O(l) + CO₂(g)

Since the concentration of the sulphuric acid is not given in the question, the assumption is made that the sulphuric acid solution is 100% sulphuric acid solution.

The density of 100% concentrated sulfuric acid is 1.839 g/mL.

Amount of acid in 0.9 mL solution = 0.9 mL * 1.839 g/mL = 1.655 g

Number of moles of acid in 1.655 g = mass/molar mass

Molar mass of  H₂SO₄ = 98 g/mol

Number of moles of acid in 1.471 g = 1.655 g / 98 g/mol = 0.0169 moles

From the equation of reaction,  1 mole of H₂SO₄  reacts with 2 moles of Na₂CO₃

0.0169 moles of H₂SO₄  will react with 0.0169 * 2 moles of Na₂CO₃ = 0.0338 moles

Therefore, 0.0338 moles of sodium bicarbonate are required to react with 0.9 mL 100% sulphuric acid solution

Answer:

[tex](C_2H_5)_3N~+~H_2O~->~(C_2H_5)_3NH^+~+~OH^-[/tex]

Explanation:

For this question, we have to remember that definition of acid and base in the Bronsted-Lowry theory:

Acid

A substance with the ability to produce a hydronium ion ([tex]H^+[/tex]).

[tex]HA~->~H^+~+~A^-[/tex]

Base

A substance with the ability to accepts a hydronium ion ([tex]H^+[/tex]).

[tex]B~+~H^+->BH^+[/tex]

If we check the reaction mechanism (figure 1). We can see that the lone pair of electrons in the "N" atom will remove an "H" from the water molecule producing a positive charge in the nitrogen and a hydroxyl group ([tex]OH^-[/tex]).

With all this in mind, the net ionic equation would be:

[tex](C_2H_5)_3N~+~H_2O~->~(C_2H_5)_3NH^+~+~OH^-[/tex]

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Answer:

Answer:

B. It's dissociation is a reversible reaction

Explanation:

NH3 is a weak alkali that does not dissociate fully into its solution. Only parts of the ammonia takes part in the dissociation process.

NH3 + H20 —> NH4+ + OH-

This dissociation is reversible which means the reactants can be formed from the product gotten from the dissociation

It has a high pH due to its basic nature. It also has a Low concentration of H+ ions and not all the OH- ions are released.

Answer:

E) C₂H₄(g) + H₂(g) ⇒ C₂H₆(g)

Explanation:

Which ONE of the following is an oxidation–reduction reaction?

A) PbCO₃(s) + 2 HNO₃(aq) ⇒ Pb(NO₃)₂(aq) + CO₂(g) + H₂O(l). NO. All the elements keep the same oxidation numbers.

B) Na₂O(s) + H₂O(l) ⇒ 2 NaOH(aq). NO. All the elements keep the same oxidation numbers.

C) SO₃(g) + H₂O(l) ⇒ H₂SO₄(aq). NO. All the elements keep the same oxidation numbers.

D) CO₂(g) + H₂O(l) ⇒ H₂CO₃(aq). NO. All the elements keep the same oxidation numbers.

E) C₂H₄(g) + H₂(g) ⇒ C₂H₆(g). YES. C is reduced and H is oxidized.

Answer; If a chemical has a pH of 3, how could you change its pH value to be more basic? Adding water to a chemical will dilute the acid, thus lowering the pH value to more basic.

If a chemical has a pH of 3, that means it is strong acid.To alter its pH value to be more basic, we have add strong base in excess.

First, neutralization reaction occur. After adding excess strong base, the solution becomes basic and pH become more basic.

The reaction between strong acid and base to form salt and water is called neutralization reaction.

Example: HCl + NaOH → NaCl + H2O

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Answer:

e. Lead

Explanation:

Hello,

In this case, since the equation to compute the heat in a heating or a cooling process is:

[tex]Q=mCp(T_2-T_1)[/tex]

We can see that the lower the specific heat of the substance, the higher the reached temperature as they are in an inversely proportional relationship. In such a way, we can say that e. Lead will reach the higher temperature if the same heat is added to same mass of the other metals.

Regards.

Answer:

2 g/mL

Explanation:

The following data were obtained from the question:

Mass (m) = 5 g

Volume (V) = 2.5 mL

Density (D) =.?

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

Density (D) = mass (m) /volume (V)

D = m/V

With the above formula, we can obtain the density of the ball as follow:

Mass (m) = 5 g

Volume (V) = 2.5 mL

Density (D) =.?

D = m/V

D = 5/2.5

D = 2 g/mL

Therefore, the density of the ball is 2 g/mL.

Answer:

H2C=CH-CH2OH

Explanation:

Aldehydes are reduced to primary alcohols.

The first step in the reaction sequence is that the nucleophilic Hydrogen atom in the hydride reagent attacks the electrophilic Carbon in the polar carbonyl group of the aldehyde, there will now be a shift of electrons from the carbonyl to the Oxygen atom creating an intermediate metal alkoxide complex.

The reaction sequence is completed by a simple addition of a proton to the alkoxide oxygen which creates the primary alcohol product from the intermediate complex.

Answer:

This question is incomplete but the completed question is below

a) Identify the chemical equation that represents what would occur if naphthalene (C₁₀H₈) is burned in the presence of O₂

b) Identify how many moles of carbon dioxide would be released from the equation in (a) if 25.0 g of naphthalene were burned in the presence of excess oxygen.

c) Explain what would happen if only 1 mole of oxygen gas were available to interact with naphthalene in this reaction.

The answers to the questions are below

Explanation:

a) The chemical reaction here will be a combustion reaction. A combustion reaction involves the burning of a substance (in this case an organic compound) in excess oxygen to produce carbon dioxide and water.

The balanced equation below shows what will happen when naphthalene (C₁₀H₈) is burned in the presence of O₂

C₁₀H₈ + 10O₂  ⇒  10CO₂ + 4H₂O

b) The mass of naphthalene (C₁₀H₈) from the equation above is

when C= 12 and H = 1; C₁₀H₈ = (10 × 12) + (1 × 8) = 128 g

Mass of C₁₀H₈ from the equation in (a) above is 128 g

If 128g of C₁₀H₈ ⇒ 10 moles of CO₂

25g of C₁₀H₈ ⇒ X moles of CO₂

where X is the unknown

X = 25 × 10/128

X = 1.95 moles of CO₂

1.95 moles of CO₂ would be released from the equation in (a) if 25.0 g of naphthalene were burned in the presence of excess oxygen

(c) If just 1 mole of oxygen gas was available for the reaction in (a) above, the reaction would have been an incomplete combustion. An incomplete combustion is the process in which a substance burns in insufficient oxygen to produce carbon monoxide (CO) and water.

Answer:

a) The solubility of the ionic compound is reduced.

Explanation:

Let AB be the ionic compound . It will ionise as follows in solution .

         AB    ⇄    A⁺  +  B⁻

In solution AB , A⁺ and B⁻ maintain a state of equilibrium . Now if we add A⁺ ion as common ion to the solution , the equilibrium will be shifted to the left ie less of AB will ionise to maintain equilibrium . Hence the solubility of AB will be reduced .

The solubility of an ionic compound reduces when any common ion is being added to any solution.

Solubility:

Ionic compound :

When some common ion adds into a solution, the solubility of a slightly soluble ionic compound gets reduced due to :

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