A student measured the gram weight of a metal object to be 5.88g. According to the supplier the object weighs 5.97g. What is the error in the student's measurement?
A. -0.09
B. +0.09​

Answer:

36.55kJ/mol

Explanation:

The heat of solution is the change in heat when the KNO3 dissolves in water:

KNO3(aq) → K+(aq) + NO3-(aq)

As the temperature decreases, the reaction is endothermic and the molar heat of solution is positive.

To solve the molar heat we need to find the moles of KNO3 dissolved and the change in heat as follows:

Moles KNO3 -Molar mass: 101.1032g/mol-

10.6g * (1mol/101.1032g) = 0.1048 moles KNO3

Change in heat:

q = m*S*ΔT

Where q is heat in J,

m is the mass of the solution: 10.6g + 251.0g = 261.6g

S is specififc heat of solution: 4.184J/g°C -Assuming is the same than pure water-

And ΔT is change in temperature: 25°C - 21.5°C = 3.5°C

q = 261.6g*4.184J/g°C*3.5°C

q = 3830.87J

Molar heat of solution:

3830.87J/0.1048 moles KNO3 =

36554J/mol =

Solution :

a). The separation of 4-methylbenzoic acid from 1,4-dimethoxybenzene will work but it will result in lower recovery.

In the reaction of acid-base to form a sodium 4 - methoxy benzoate, that is soluble in the water, 4-methoxy benzoic acid reacts with the sodium bicarbonate to give sodium 4-methoxybenzoate as well as carbonic acid.

b). The pKa for the 4-methoxybenzoic acid is [tex]4.46[/tex], and that of carbonic acid is [tex]6.37[/tex]

c). The Keq for the reaction is [tex]10(6.37 - 4.46) = 101.91[/tex]

Therefore, the equilibrium lies to the right  and also the reaction favors the products and the separation works.

But the recovery will be low when compared to the extraction with Sodium hydroxide as the strong base will drive the equilibrium further to the right position, thus neutralizing all the acids virtually. And the weak base will partially neutralize the acid.

The question is incomplete, the complete question is:

What volume (mL) of the sweetened tea described in Example 3.14 contains the same amount of sugar (mol) as 10 mL of the soft drink in this example. The example is attached below.

Answer: 75 mL of sweetened tea will contain the same amount of sugar as in 10 mL of soft drink

Explanation:

We first calculate the number of moles of soft drink in a volume of 10 mL

The formula used to calculate molarity:

[tex]\text{Molarity of solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (mL)}}[/tex] .....(1)

Taking the concentration of soft drink from the example be = 0.375 M

Volume of solution = 10 mL

Putting values in equation 1, we get:

[tex]0.375=\frac{\text{Moles of sugar in soft drink}\times 1000}{10}\\\\\text{Moles of sugar in soft drink}=\frac{0.375\times 10}{1000}=0.00375mol[/tex]

Calculating volume of sweetened tea:

Moles of sugar = 0.00375 mol

Molarity of sweetened tea = 0.05 M

Putting values in equation 1, we get:

[tex]0.05=\frac{0.00375\times 1000}{\text{Volume of sweetened tea}}\\\\\text{Volume of sweetened tea}=\frac{0.00375\times 1000}{0.05}=75mL[/tex]

Hence, 75 mL of sweetened tea will contain the same amount of sugar as in 10 mL of soft drink

Explanation:

So, first you will want to write the balanced chemical equation for this reaction.

Butane = [tex]C_4H_{10}[/tex]

[tex]2C_4H_{10}+13O_2=>10H_2O+8CO_2[/tex]

^ This ends up being your balanced chemical equation. Now, you can do the math!

[tex]1.57gC_4H_{10}*\frac{1molC_4H_{10}}{58.12gC_4H_{10}}*\frac{10molH_2O}{2molC_4H_{10}}*\frac{18gH_2O}{1molH_2O}[/tex]

After plugging this into a calculator, your final mass of water should be:

2.43gH2O

Answer:

A

Explanation:

because solid stick together like magnetic and can feel every vibration

Answer:D

Explanation: on the surface of a solid

Answer:

Carboxyl, primary amine, amide, ester, and phenyl.

Explanation:

The functional groups present in the compound of aspartame are carboxyl, primary amine, amide, ester, and phenyl. Aspartame is an artificial non-saccharide sweetener which is 200 times sweeter than sucrose. This aspartame is commonly used as a sugar substitute in many foods and beverages. It has the trade names such as NutraSweet, Equal, and Canderel.

The question is incomplete, the complete question is shown in the image attached

Answer:

A and B

Explanation:

The electrophilic substitution of arenes yields a cation intermediate. The positive charge of the cation is delocalized over the entire ring.

The -CN group directs incoming electrophiles to the ortho/para position. The resonance structures for the chlorination of benzonitrile are shown in the question.

Recall that -CN is an electron withdrawing group. The resonance forms that destablize the carbocation intermediate are those in which the -CN group is directly attached to the carbon atom bearing the positive charge as in structures A and B.

Answer:

A sample of calcium fluoride was decomposed into the constituent elements. Write a balanced chemical equation for the decomposition reaction. If the sample produced 294 mg of calcium, how many g of fluorine was formed

Explanation:

The balanced chemical equation for the decomposition of calcium fluoride is shown below:

[tex]CaF_2(s)->Ca(s)+F_2(g)[/tex]

The sample produced 294 g of calcium then, how many grams of fluorine is formed?

From the balanced chemical equation,

1 mol of CaF2 forms 1mol of calcium and 1 mol of fluorine.

That is:

40g of calcium and 38.0 g of fluorine are formed.

then,

If 294 g of calcium is formed then how many grams of fluorine is formed?

[tex]294g Ca * 38g F2 / 40g Ca\\=279.3 g F_2[/tex]

Hence, 279.3 g of fluorine will be formed.

Answer:

As either mass increases, the gravitational force between them

increases.

Explanation:

According to Newton's law of universal gravitation;

F α m1m2/r^2

That is, the force between two masses in a gravitational field is directly proportional to the product of the two masses and inversely proportional to their distance apart.

Hence, as either of the masses increase, the force of gravitation between the two masses increases. Hence the answer.

Answer:

Explanation:

This is a halogenation reaction i.e substitution or replacement of a single or more than a single hydrogen atom in the organic alkane compound with the halogen(here it is chlorine).

The chlorination of 1-chloro-2,2,3,3-tetramethylpentane under UV light resulted in the formation of five (5) dichloro derivatives which are shown in the image attached below.

Also, the compounds containing a stereocenter (i.e a location within the compound composing of various substituents in which the interchangeability of these substituents has the tendency of resulting into a stereoisomer) are indicated with an asterisk in the image below.

From the image below:

compound 1 ⇒  1,1-dichloro-2,2,3,3-tetramethylpentane = 2° C

∴

The given relative reactivity rate for 2°  = 3.6x

For compound 2 ⇒  1,4-dichloro-2,2,3,3-tetramethylpentane = 2°  = 3.6x

For compound 3 ⇒ 1,5-dichloro-2,2,3,3-tetramethylpentane = 1°  = 1x

For compound 4 ⇒ 1-chloro-2-chloromethyl-2,3,3-trimethylpentane

= 1°  = 1x

For compound 5 ⇒ 1-chloro-3-chloromethyl-2,2,3-trimethylpentane

= 1°  = 1x

As such, we have:

2(3.6x) + 3(1x) = 100

7.2x + 3x = 100

10.2x = 100

x = 100/10.2

x = 9.803°

∴

For compound (1) = 3.6(9.803) = 35.3%

For compound (2) = 3.6(9.803) = 35.3%

For compound (3) = 1(9.803) = 9.803°%

For compound (4) = 1(9.803) = 9.803°%

For compound (5) = 1(9.803) = 9.803°%

Answer:

First, the number of ammonium sulfide molecules should be calculated:

N = NA × n,

where NA - the Avogadro number, n - number of moles.

N (ammonium sulfide) = 6.022 × 1023 × 8.5 mol = 51.187 × 1023.

The moelcular formula of ammonium sulfide is (NH4)2S. It means that each molecule contains 8 hydrogen atoms.

As a result, 8.5 mol of (NH4)2S contain:

51.187 × 1023 × 8 = 41 × 1024 hydrogen atoms.

Answer: 41 × 1024 hydrogen atoms

Answer:

1.20x10⁻²⁰μL

Explanation:

1cm³ is equal to 1milliliter. As we must know, 1milliliter = 1000 microliters, 1000μL. To convert the 1.20x10⁻²³mL we need to use the conversion factor: 1mL = 1000μL.

The volume of tantalum in μL is:

1.20x10⁻²³mL * (1000μL /1L) = 1.20x10⁻²⁰μL

Answer:

Explanation:

Answer is D 2,5-dimethylheptanal

You should accern the lowest possible number close to the parent name

Answer: The density of the given vapor is 0.939 g/L.

Explanation:

Given: Pressure = 233 mm Hg (1 mm Hg = 0.00131579 atm) = 0.31 atm

Temperature = [tex]25^{o}C[/tex] = (25 + 273) K = 298 K

According to the ideal gas equation,

[tex]PV = \frac{m}{M}RT[/tex]

where,

P = pressure

V = volume

m = mass

M = molar mass

R = gas constant = 0.0821 L atm/mol K

T = temperature

This formula can be re-written as follows.

[tex]PM = \frac{m}{V}RT[/tex]    (where, [tex]Density = \frac{mass (m)}{Volume (V)}[/tex] )

Hence, formula used to calculate density of diethy ether (molar mass = 74.12 g/mol) vapor is as follows.

[tex]d = \frac{PM}{RT}[/tex]

Substitute values into the above formula as follows.

[tex]d = \frac{PM}{RT}\\= \frac{0.31 atm \times 74.12 g/mol}{0.0821 L atm/mol K \times 298 K}\\= \frac{22.9772}{24.4658}\\= 0.939 g/L[/tex]

Thus, we can conclude that the density of the given vapor is 0.939 g/L.

Answer:

"Esters are widespread in nature and are widely used in industry. In nature, fats are in general triesters derived from glycerol and fatty acids. Esters are responsible for the aroma of many fruits, including apples, durians, pears, bananas, pineapples, and strawberries."

Explanation:

Answer:

The answer is "It takes 1,70 mol of ethanol".

Explanation:

To make acetic acid, we must first write the balanced reaction that occurs of ethanol with oxygen

The response is balanced:

[tex]CH_3CH_2OH+O_2\to CH_3COOH+H_2O[/tex]

1 mol of ethanol creates 1 mol of According the equilibrium Ethanol moles, therefore, required 1.70 mol of water = 1.70 mol

Explanation:

This is a decomposition reaction. Firstly, you will want to write the chemical equation out and balance it.

[tex]2Hg_2O->4Hg+O_2[/tex] (The -> is supposed to be an arrow, sorry!)

We see that there's only 1mol of Oxygen made in the products, we can do some simple math to solve for the amount of grams of Oxygen produced according to the amount of the reactant (Hg2O).

[tex]32.2gHg_2O*\frac{1molHg_2O}{417.18gHg_2O}*\frac{1molO_2}{2molHg_2O}*\frac{32gO_2}{1molO_2}[/tex]

I want to break this down, just in case:

The 417.18gHg2O is the molecular mass of the molecule (so I doubled Hg and added 16 to it to get this number).

As we can see in the chemical equation, 1mol Hg2O produces 2mol O because Oxygen is a diatomic molecule (so there will always be two of it when it's by itself).

And finally, in 1mol O2 there are 32g of O2.

** When you do math like this, always make sure that all of your units cancel out except for the units you're looking for. For example, here we're looking for the grams of Oxygen, so after everything else cancels out, we should only have grams O2.

So, 1.23gO2 should be your answer.

Answer:

0.1 L

Explanation:

From the question given above, the following data were obtained:

Concentration of stock solution (C₁) = 1.25 M

Volume of diluted solution (V₂) = 0.5 L

Concentration of diluted solution (C₂) = 0.25 M

Volume of stock solution needed solution (V₁) =?

The volume of the stock solution needed can be obtained as follow:

C₁V₁ = C₂V₂

1.25 × V₁ = 0.25 × 0.5

1.25 × V₁ = 0.125

Divide both side by 1.25

V₁ = 0.125 / 1.25

V₁ = 0.1 L

Therefore, the volume of the stock solution needed is 0.1 L

Answer:

When this equation is solved, the two values of the unknown are 0.0643 and -0.082

Explanation:

Given

[tex]1.77 * 10^{-2} = \frac{x^2}{0.298 - x}[/tex] --- the actual equation

Required

The values of x

We have:

[tex]1.77 * 10^{-2} = \frac{x^2}{0.298 - x}[/tex]

Cross Multiply

[tex]1.77 * 10^{-2} * (0.298 - x)= x^2[/tex]

Multiply both sides by 100

[tex]1.77 * (0.298 - x)= 100x^2[/tex]

Open bracket

[tex]0.52746 - 1.77x= 100x^2[/tex]

Rewrite as:

[tex]100x^2 + 1.77x - 0.52746 =0[/tex]

Using quadratic formula:

[tex]x = \frac{-b \± \sqrt{b^2 - 4ac}}{2a}[/tex]

Where:

[tex]a = 100; b = 1.77; c = -0.52746[/tex]

So, we have:

[tex]x = \frac{-1.77 \± \sqrt{1.77^2 - 4*100*- 0.52746 }}{2*100}[/tex]

[tex]x = \frac{-1.77 \± \sqrt{214.1169}}{2*100}[/tex]

[tex]x = \frac{-1.77 \± 14.63}{200}[/tex]

Split

[tex]x = \frac{-1.77 + 14.63}{200}\ or\ x = \frac{-1.77 - 14.63}{200}[/tex]

[tex]x = \frac{12.86}{200}\ or\ x = \frac{-16.40}{200}[/tex]

[tex]x = 0.0643\ or\ x = -0.082[/tex]

Answer:

antimony-121 has the highest percent natural abundance

Explanation:

percent natural abundance;

121.76 = 120.90 x + 122.90 (1 - x)

121.76 = 120.90 x + 122.90 - 122.90x

121.76 = -2x + 122.90

121.76 - 122.90 = -2x

x= 121.76 - 122.90/ -2

x= 0.57

Where x and 1 - x refers to the relative abundance of each of the isotopes

Percent natural abundance of antimony-121 = 57 %

Percent natural abundance of antimony-123 = (1 - 0.57) = 43%

Let us remember that isotopy refers to a phenomenon in which atoms of the same element have the same atomic number but different mass numbers. This results from differences in the number of neutrons in atoms of the same element.

We can clearly see that antimony-121 has the highest percent natural abundance.

Answer:

I don't know what to do

Explanation:

bye

Answer:

a. Single DNA strand used to produce mRNA ⇒ Transcription

b. Requires tRNA ⇒ Translation

c. Ribosome ⇒ Translation

d. DNA polymerase ⇒ Replication

e. Both DNA strands are duplicate  ⇒ Replication

f. Described as semi-conservative  ⇒ Replication

g. Amino acids added to peptide chain ⇒ Translation

Explanation:

Replication: the double-strand DNA is separated into two strands. Each strand is used as a template by DNA polymerase to produce the other strand. The leading strand is read by DNA polymerase in a continuous form (3' - 5') and the lagging strand is read in a discontinuous form (5'-3'). In this way, both strands are duplicated. The process is semi-conservative because the DNA molecule produced conserves 1 original strand and the other strand is the new synthesized one. The corresponding options are: d, e, f.

Transcription: is a process in which the genetic code of DNA is copied into a molecule called messenger RNA (mRNA). The double-strand DNA is opened and one strand is read. The enzyme involved is RNA polymerase, which binds the DNA (in a sequence called promoter) and uses the nucleotide code of DNA as a template to produce a molecule of RNA (the mRNA). Therefore, the correct option for this process is a.

Translation: is the process in which the mRNA sequence (copied from a DNA molecule) is translated into an amino acid sequence to produce a protein. This process is carried out within the cell ribosome. The mRNA is read in groups of three nucleotides (a codon) that codifies amino acids. The translation between codon and amino acid is assisted by molecules called transference RNA (tRNA). As each codon is decoded, an amino acid is added and the new polypeptide sequence is synthesized. Therefore, the correct options are: b, c, g.

Answer:

21.63 %

Explanation:

The molar mass of Mn₃[Mn(CO)₄]₃ is 665.64 g/mol.

Let's assume we have 1 mol of Mn₃[Mn(CO)₄]₃, if that were the case then we would have 665.64 grams.

There are 12 C moles per Mn₃[Mn(CO)₄]₃, with that in mind we calculate the weight of 12 C moles:

Finally we calculate the mass percent of carbon:

Answer: There are 0.779 moles of gas were added to the bottle.

Explanation:

Given: [tex]n_{1}[/tex] = 0.650 mol,     [tex]P_{1}[/tex] = 730 mm Hg (1 mm Hg = 0.00131579 atm) = 0.96 atm

[tex]n_{2}[/tex] = ?,           [tex]P_{2}[/tex] = 1.15 atm

Formula used is as follows.

[tex]\frac{P_{1}}{n_{1}} = \frac{P_{2}}{n_{2}}[/tex]

Substitute the values into above formula as follows.

[tex]\frac{P_{1}}{n_{1}} = \frac{P_{2}}{n_{2}}\\\frac{0.96 atm}{0.650 mol} = \frac{1.15 atm}{n_{2}}\\n_{2} = 0.779 mol[/tex]

Thus, we can conclude that there are 0.779 moles of gas were added to the bottle.

Answer:

Calcium

Explanation:

Zinc cannot displace Ca because calcium is above it in the reactivity series

Water is in the solid phase at 0.25 atm and 0°C.

A pressure of 50 kPa and a temperature of 50 °C correspond to the “water” region—here, water exists only as a liquid. At 25 kPa and 200 °C, water exists only in the gaseous state.

Under standard atmospheric conditions, water exists as a liquid. But if we lower the temperature below 0 degrees Celsius, or 32 degrees Fahrenheit, water changes its phase into a solid called ice.

Learn more about the solid phase here https://brainly.com/question/13396621

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Answer:

d

Explanation:

Answer:

a

Explanation:

documentary is best researcher!.

Answer:

high melting point

Explanation:

The filament of a bulb is often heated to very high temperatures as the bulb is in operation.

Many times, electric bulbs may have to be on for a whole day and they may reach temperatures that are outrageously high in the process.

The material of the filament must have a very high melting point so that it doesn't melt while the bulb is still in operation.

Answer:

Actually the answer is High Vapor pressure

Explanation:

Answer:

Explanation:

From the given information:

Camphor may be reduced as readily in the presence of sodium borohydride(NaHB4). The resulting compound which is stereoselective requires 1 mole of sodium borohydride (NaHB4) to reduce 1 mole of camphor in this reaction. The reaction is shown below.

Through the reduction process of camphor, the reducing agent can reach the carbonyl face with a one-carbon linkage. The product stereoisomer is known as borneol.

If the molecular weight of camphor = 152.24 g/mol

and it mass = 200 mg

The its no of moles = 200 mg/ 152.24 g/mol

= 1.3137 mmol

Now the amount of the required mmol for NaBH4 to be consumed in the reaction = 5.2 × 1.3137 mmol

= 6.831 mmol

since the molar mass of NaBH4 = 37.83 g/mol

Then, using the same formula:

No of moles = mass/molar mass

mass = No of moles × molar mass

mass = 6.831 mmol × 37.83 g/mol

mass of NaBH4 used = 258.42 mg