Four research teams measured the length of a rare whale, and what each team wrote in its team notebook is shown in the table below.
Suppose a later and more reliable measurement gives 45.0 m for the length of the same whale. Decide which of the earlier measurements was the most
accurate, and which was the most precise.
team
what was written
in the notebook
most accurate
measurement
most precise
measurement
?
A
"55.m"
B
*50.0m +0.5m
с
*44.0m + 6.0%
D
o
"between 30 m and 40 m

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:

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:

(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:

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:

Molar solubility of magnesium fluoride (MgF2) = 8.26 × 10⁻¹⁰ M

Explanation:

Given:

Ksp = 5.16 × 10⁻¹¹

NaF = 0.250

Find:

Molar solubility of magnesium fluoride (MgF2)

Computation:

Molar solubility of magnesium fluoride (MgF2) = Ksp / NaF²

Molar solubility of magnesium fluoride (MgF2) = 5.16 × 10⁻¹¹ / (0.250)²

Molar solubility of magnesium fluoride (MgF2) = 8.26 × 10⁻¹⁰ M

The molar solubility of magnesium fluoride (MgF2) is 8.26 × 10⁻¹⁰ M.

Since

Ksp = 5.16 × 10⁻¹¹

NaF = 0.250

Now we know that

Molar solubility of magnesium fluoride (MgF2) = Ksp / NaF²

= 5.16 × 10⁻¹¹ / (0.250)²

= 8.26 × 10⁻¹⁰ M

hence, The molar solubility of magnesium fluoride (MgF2) is 8.26 × 10⁻¹⁰ M.

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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:

Please find the attachment to this question:

Explanation:

By eliminating the agent produced in the reaction, it will give a structure of the alkene. please find the given attachment.

Answer:

pH will be increased.

Explanation:

When you mixed sodium acetate and acetic acid,  pH will be maintained and will have slight changes. This constitutes what is known as a buffer solution.

But if you analize the reactions:

First of all, you have a weak acid, acetic:

CH₃COOH   +  H₂O  ⇄  CH₃COO⁻  +   H₃O⁺      Ka

And the salt can be dissociated as:

NaCH₃COO →  CH₃COO⁻  +   Na⁺

As you are adding acetate, this is the conjugate strong base from the weak acid and as every base, it brings hydroxides to medium, so the pH will be increased. Protons from the acid will be neutralized, thouhgh.

CH₃COO⁻  +   H₂O  ⇄  CH₃COOH + OH⁻     Kb

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; 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:

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:

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]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:

Mass, m = 1.51 grams

Explanation:

It is given that,

The circumference of Aluminium cylinder, C = 13 mm = 1.3 cm

Length of the cylinder, h = 4.2 cm

We know that the density of the Aluminium is 2.7 g/cm³

Circumference, C = 2πr

[tex]r=\dfrac{C}{2\pi}\\\\r=\dfrac{1.3}{2\pi}\\\\r=0.206\ cm[/tex]

Density is equal to mass per unit volume.

[tex]d=\dfrac{m}{V}[/tex]

m is mass of the cylinder

V is the volume of the cylinder

[tex]V=\pi r^2h\\\\V=\dfrac{22}{7}\times0.206^2\times 4.2\\\\V=0.5601\ cm^3[/tex]

So,

[tex]m=d\times V\\\\m=2.7\times 0.5601\\\\m=1.51\ g[/tex]

So, the mass of the cylinder is 1.51 grams.

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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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:

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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please mark it the brainliest!

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

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:

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:

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:

d. sodium t-butoxide + bromomethane

Explanation:

Sodium t-butoxide is a strong base with the chemical formula  (CH3)3CONa and it is a non-nucleophilic base while bromomethane with the chemical formula CH3Br.

They both together gives 2-ethoxypropane (C5H12O).

(CH3)3CONa + CH3Br => C5H12O + NaBr

Hence, the correct option is "d".

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:

[tex]v_{rms}=866.32m/s[/tex]

Explanation:

Hello,

In this case, since the rms speed of the molecules is computed by:

[tex]v_{rms}=\sqrt{\frac{3RT}{M} }[/tex]

Whereas the absolute temperature is computed from the internal energy (by using the Cp of helium (3.1156 J/g*K) as shown below:

[tex]U=nCvT\\\\T=\frac{U}{nCv}=\frac{15kJ*\frac{1000J}{1kJ} }{10mol*\frac{4.00g}{1mol} *3.1156\frac{J}{g*K} } \\\\T=120.36K[/tex]

Thereby, the rms speed results:

[tex]v_{rms}=\sqrt{\frac{3*8.314\frac{kg*m^2}{s^2*mol*K}*120.36K}{4.00\frac{g}{mol}*\frac{1kg}{1000} } } \\\\v_{rms}=866.32m/s[/tex]

Regards.

Answer:

Nonmetallic elements form ions by gaining valence electrons to complete their outer shell.

The more valence electrons an element has in its outer shell, the easier it is to complete.

The fewer electron shells an element has, the easier it is to fill its outermost shell.

Reactivity in nonmetals increases as you go from left to right in a group, and

decreases as you go from top to bottom.

Explanation:

Nonmetallic elements form ions by gaining valence electrons to complete

their outer shell.

The more valence electrons an element has in its outer shell, the easier it is to complete.

The fewer electron shells an element has, the easier it is to fill its outermost shell.

Reactivity in nonmetals increases as you go from left to right in a group, and decreases as you go from top to bottom.

When there are more valence electrons then it makes it easy for the element

to complete its outermost shell as against if it was less as it would be harder

due to a bigger number of electrons needed.

Non metals are elements which accepts valence electrons to complete its

outermost shell and becomes negatively charged when this happens.

When an element has fewer electron shells then filling the outermost shell

will be easier as the electron shells require a lesser number of electrons and

increases as the number of shells increases.

This is because the tendency to accept electrons increases from left to right

and decreases down the group.

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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:

1. For the central boron atom:

A. The number of lone pairs = 0.

B. The number of single bonds = 3.

C. The number of double bonds = 0.

2. The central boron atom B. Has an incomplete octet.

Explanation:

Hello,

In this case, as shown on the attached picture containing the required Lewis structure of boron chloride, we can see that:

1. For the central boron atom:

A. The number of lone pairs = 0 since all the three valance electrons are bonded with the chlorine atoms.

B. The number of single bonds = 3 as each chlorine atom needs only one bond to obey the octet.

C. The number of double bonds = 0 considering the previous explanation.

2. The central boron atom B. Has an incomplete octet since it reaches six electrons only from its initial three and other three provided by the three chlorine atoms.

Regards.

Answer:

[tex][Cu]^{remaining}=0.357 M[/tex]

Explanation:

Hello,

In this case, we may use the following equation in order to compute the moles of copper that are processed, considering it goes from Cu⁰ to Cu²⁺, so two electrons are transferred:

[tex]n_{Cu}=\frac{2.68C/s*282s}{96500C/mol*2} =3.9x10^{-3}mol[/tex]

After that, we compute the initial moles of copper in the solution, considering that the concentration of copper (II) equals the concentration of copper:

[tex]n_{Cu,0}=0.366mol/L*0.425L=0.156mol[/tex]

In such a way, we can subtract the process moles to the initial moles to compute the remaining moles of copper:

[tex]n_{Cu}^{remaining}=0.156mol-0.0039mol=0.152mol[/tex]

Finally, the concentration is:

[tex][Cu]^{remaining}=0.152mol/0.425L[/tex]

[tex][Cu]^{remaining}=0.357 M[/tex]

Regards.

Answer:

[tex]V_2=19.23L[/tex]

Explanation:

Hello,

In this case, by using the Avogadro's law which allows us to understand the volume-moles behavior as a directly proportional relationship:

[tex]\frac{V_2}{n_2} =\frac{V_1}{n_1}[/tex]

We can compute the volume of 34.3 g of argon by representing it in mole as shown below:

[tex]n_1=1 mol\\\\n_2=34.3g*\frac{1mol}{39.95g} =0.859mol[/tex]

Thus, we find:

[tex]V_2=\frac{V_1*n_2}{n_1}=\frac{22.4L*0.859mol}{1mol} \\\\V_2=19.23L[/tex]

Best regards.

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:

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