What is the total number of electrons in an atom of an element with an atomic number of 18 and a mass number
of 40?
a. 58
c. 22
b. 18
d. 40

Rate of the reaction is the speed at which the chemical reaction takes place.

The rate of reaction is the rate of disappearance of reactant or rate of appearance of product per unit period of time that is  per second, minute or hour. The rate of reaction is the rate of disappearance of reactant or rate of appearance of product per unit period of timethat is per second, minute or hour. It is proportional to the increase in concentration of a product in unit time and decrease in the concentration of the reactant in unit time.  The speed of a chemical reaction may be defined as the change in concentration of a substance divided by the time interval during which the changes occurs.

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The amine that will react with cyclopentanone to form an enamine is CH3CH2CH2CH2NH2. This is a primary amine, which is required for enamine formation.

Enamine formation is a reaction between a primary amine and a carbonyl compound (such as cyclopentanone).

During this reaction, the nitrogen atom of the amine attacks the carbonyl carbon of the carbonyl compound, leading to the formation of an imine intermediate. This intermediate can undergo tautomerization to form the final enamine product.

In order for this reaction to occur, a primary amine is required, as it has a more reactive nitrogen atom compared to secondary or tertiary amines. CH3CH2CH2CH2NH2 is a primary amine, as it has only one carbon atom attached to the nitrogen atom.

Therefore, it is the correct choice for reacting with cyclopentanone to form an enamine.

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Answer:

becoz vvv is always with you

Answer:

Alkali metals have one valence electron on their outer shell. They are more stable when they have eight valence electrons so they tend to loose that one electron and obtain a full octet, therefore become stable

Answer:

Let's walk through this together, and pay close attention. The answers are bolded and underlined but I insist you to read through the whole thing and understand what's being applied here.

Write down the balanced equation first:

\(Pb(NO_{3})_{2} \ + \ 2KI \ ----- > \ PbI_2 \ + \ 2KNO_{3}\)

  24g              30g                         ???

To find the limiting reactant, convert both of the masses to moles and the lowest one is the limiting reagent.

Molar mass of Lead (II) Nitrate: 331.2g/mol

Molar mass of Potassium Iodide: 166g/mol

Remember: \(moles \ = \ \frac{mass}{molar \ mass}\)

\(\frac{24}{331.2} = 0.0724 \ mol\ of\ Lead \ (II) \ Nitrate\\\\\frac{30}{166} = 0.180 \ mol \ of \ Potassium \ Iodide\)

As you can see here, the compound with the lower mol value is Lead (II) Nitrate, meaning Lead (II) Nitrate is our limiting reactant.

To find the excess reactant which is the other reactant present, Potassium Iodide, you must do the mol to mol ratio of Lead (II) Nitrate to Potassium Iodide (Basically the numbers in front/coefficients of the compound in the balanced equation)

The ratio is 1 : 2, meaning you have to multiply the amount of mol of Lead (II) Nitrate by 2 to get the mol of Potassium Iodide.

\(0.0724 \ * \ 2 = \ 0.1448 \ mol \ of \ Potassium \ iodide\)

Now we change the mol into mass by multiplying it by the molar mass of potassium iodide

\(0.1448 \ * \ 166 = \ 24.04g \ of \ Potassium \ iodide\)

To get the amount of excess reactant, you have to subtract the original mass amount you had which was 30g by the mass you just got which is 24.04g

30 - 24.04 = 5.96g of Potassium Iodide is in excess left over

Our final question is to calculate the percentage yield of lead iodide, which we can do so by dividing the actual yield produced by the theoretical yield, and multiplying the answer of that by a 100 to get the percent.

We have our experimental yield which is 32.5g but we don't have our theoretical. We have to calculate it using our limiting reactant and mol ratios. The ratio of Lead (II) Nitrate to Lead (II) Iodide is 1 : 1 so all we have to is to change 0.0724 mol into the mass value by multiplying the mol with the molar mass of Lead (II) Iodide.

Molar mass of Lead (II) Iodide: 461.01g/mol

\(0.0724 \ * \ 461.01 = \ 33.4g\)

So the theoretical yield is 33.4g and the actual yield was 32.5g

\(\frac{32.5}{33.4} * 100 = 97.3 \ percent\)

The percentage yield of Lead (II) Iodide is 97.3%

The molecular formula of the gas is \(CH_2\) and it has a molar mass of 6. 0 g/mol.  

The empirical formula of a compound is the lowest whole-number ratio of the numbers of atoms of each element that combine to form the compound. The molecular formula of a compound is the actual number of atoms of each element in a molecule of the compound.

The molecular formula of a compound, we need to use the molar mass of the compound and the molar mass of each element in the compound. We can also use the empirical formula to calculate the molar mass of the compound by multiplying the molar mass of each element in the empirical formula by the ratio of the number of atoms of each element in the compound to the empirical formula.

For example, if the molar mass of carbon is 12. 0 g/mol, the molar mass of hydrogen is 1. 0 g/mol, and the empirical formula of a gas is  \(CH_2\), the molecular formula of the gas can be calculated as follows:

Molar mass of carbon (C) = 12. 0 g/mol

Molar mass of hydrogen (H) = 1. 0 g/mol

Molar mass of  \(CH_2\) gas = molar mass of carbon x molar mass of hydrogen / empirical formula

Molar mass of  \(CH_2\) gas = 12. 0 g/mol x 1. 0 g/mol /  \(CH_2\)

Molar mass of  \(CH_2\) gas = 12. 0 g/mol / 2

Molar mass of  \(CH_2\) gas = 6. 0 g/mol

Therefore, the molecular formula of the gas is  \(CH_2\), and it has a molar mass of 6. 0 g/mol.  

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Answer:

33.4814814815

Explanation:

90.4/2.70

If a gas in a balloon occupies 2.25 L at 298 K and 300 kPa, the temperature at which the balloon expand to 3.50L and 2.17 atm is 345.23K.

The temperature of an ideal gas can be calculated using the following formula:

P1V1/T1 = P2V2/T2

Where;

According to the information given in this question;

2.96 × 2.25/298 = 2.17 × 3.5/T2

0.022T2 = 7.595

T2 = 7.595 ÷ 0.022

T2 = 345.23K

Therefore, if a gas in a balloon occupies 2.25 L at 298 K and 300 kPa. the temperature at which the balloon expand to 3.50L and 2.17 atm is 345.23K.

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Answer:

basic

Explanation:

(a) -  1.39 atm is the partial pressure of the hydrogen gas in the sample

(b) -  0.219 g many grams of aluminum must have reached to produce this quantity of hydrogen gas.

According to Dalton's Law, often known as the Legislation of Partial Pressures, the combined pressure of a mix of gas is equal to the product of their individual partial pressures.

(a)The partial pressure of hydrogen gas and the vapour pressure of water are added to determine the total pressure of the gas mixture.

PT = Pw + PH

Water has a vapour pressure of atm.

Pw = (30.75 torr)(1.00 atm) / 760 torr

Pw = 0.0405 atm

The hydrogen gas pressure is

PH = PT - Pw

PH = 1.44 atm - 0.0405 atm

PH = 1.39 atm

(b) The amount of hydrogen gas in moles is

n = PV / RT

n = (1.39 atm) (0.2384 L)  / 0.82057 atm L / mol K (302.6 K)

n=0.0122 mol

Aluminum metal and hydrogen gas have a 3:2 molar ratio. The required amount of aluminum metal in moles is

n=0.0122 mol * 2 / 3

n = 0.00813 mol

Aluminum has a molar mass of 26.981538 g/mol. The quantity of aluminum needed is

m = 0.00813 * 26.981538 g/mol

m = 0.219 g

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The complete question is -

Hydrogen gas is produced by the reaction between metallic aluminum and aqueous hydrochloric acid. 2al(s) 6hcl(aq)⟶2alcl3(aq) 3h2(g)

(a)the hydrogen gas produced by this reaction is typically collected via water displacement. during this process, the hydrogen gas becomes saturated with water vapor. if 292.6 ml of gas with a total pressure of 1.44 atm is collected via water displacement at 29.4 ∘c , what is the partial pressure of the hydrogen gas in the sample?

(b)How many grams of aluminum must have reached to produce this quantity of hydrogen gas ? The vapor pressure of water at 29.4 ∘c is 30.75 torr.

Answer:

characteristic of a good claim:

1. written in complete sentences

2. one sentence

3. answers one question

4. is stated as a fact

5. doesn't attempt to explain the claim

not a characteristic of a good claim:

1. multiple sentences

2. does not contain punctuation

3. answers multiple questions

4. starts with "i think"

5. attempts to explain the claim

6. uses weak words like "probably"

Explanation:

it is what it is

To make a 1 molar solution of 100 mL, you would need approximately 34.23 grams of powdered drink mix (\(C_{12}H_{22}O_{11}\)).

To determine the mass of powdered drink mix needed to make a 1.0 M solution, we need to use stoichiometry and the molar mass of the compound. In this case, the powdered drink mix is represented by the compound \(C_{12}H_{22}O_{11}\) (sucrose).

The molarity (M) is defined as moles of solute per liter of solution. Therefore, for a 1.0 M solution with a volume of 100 mL (0.1 L), we have:

Moles of sucrose = Molarity × Volume = 1.0 mol/L × 0.1 L = 0.1 mol.

We calculate the molar mass of sucrose:

Molar mass of \(C_{12}H_{22}O_{11}\)

= 12.01 g/mol × 12 + 1.01 g/mol × 22 + 16.00 g/mol × 11

= 144.12 g/mol + 22.22 g/mol + 176.00 g/mol

= 342.34 g/mol.

Finally, we can calculate the mass of powdered drink mix needed:

Mass of powdered drink mix

= Moles of sucrose × Molar mass of C12H22O11

= 0.1 mol × 342.34 g/mol

= 34.23 g.

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Answer:

NMR (Nuclear magnetic resonance) is modern spectroscopy technique to study a variety of nuclei for e.g. 1H NMR, 2H NMR, 13C NMR, 15N NMR, 19F NMR etc

When any nuclei is place in any external magnetic field it starts spinning according to flamings right hand rule & the angular frequency of nuclei is called as Larmor Frequency (ω), and the charged nuclie generates oscillating electric field . There are two energy states Alpha state and Beta state depending on the alignment of spinning nuclie.

If radiowave of frequency (ω) is supplied to the operation the two electric field couples and energy gets absorbed by the nucleus this process is known Resonance.

Depending on the environment of all protons, not all protons absorbs the same amount of energy and the protons are shielded by electrons from the external magnetic field.

Tetramethylsilane (TMS) is used for 1H and 13C NMR, have the delta shift value of 0 PPM

\( \sf \: \delta \: shift = \frac{shift \: from \: TMS \: in \: Hz}{spectrometer \: frequency \: in\: MHz} \)

The number of signals of any compound depends on the chemical shift, at every specific shift NMR shows a signal.

Let's understand step by step:

Consider the simplest organic molecule in Organic chemistry methane, methane have only one carbon atom hence it shows only One 13C NMR signal.

Let's move to ethane, ethane have two carbon atoms but the environment of both carbon atom are same that they are terminal carbon bounded to 3 H atoms each. since the chemical environment of both the Carbon atom is same it will again show only One 13C NMR signal.

Now coming to propane, propane have three carbon atoms, two on terminal (methyl groups) and one that is in middle touching both the carbon atoms, the Chemical environment of terminal two carbons are same so they both together will show one peak and the middle carbon(-CH2 group) have different environment so it will show the signal at different shift. Hence the total number of 13C NMR signal would be two!

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The volume of the sodium carbonate needed to precipitate is 31.248 ml. This is calculated using the dilution formula.

The molarity of the solution and the volume of the first solution can be correlated with the molarity and the volume of diluted solution. It is called as dilution formula.

Molar concentration is the another term for molarity. Molarity is a measure of the concentration of a chemical species in particular of a solute in a solution in terms of amount of substance per unit volume of solution.

The expression for molarity of the solution is,

M1 V1 = M2 V2

here we have 0.125 m sodium carbonate solution would be needed to precipitate the calcium ion from 37.2 ml of 0.105 m cacl2 solution.  

putting all the values we get,

0.105 * 37.2 = 0.125 * V2

V2 = 31.248

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Answer:

0.167 M NaOH

Explanation:

Answer:

0.167

Explanation:

If one strand of a DNA molecule has the sequence of bases 5'-ATTGCA-3', the other complementary strand would have the sequence 5'-TGCAAT-3'.

The complementary strand of DNA would have the sequence 5'-TGCAAT-3' if one strand of a DNA molecule has the sequence of bases 5'-ATTGCA-3'.There are a number of rules governing which bases pair with each other. In DNA, Adenine (A) pairs with Thymine (T), and Guanine (G) pairs with Cytosine (C).

Therefore, because A and T pair together and G and C pair together, the complementary strand can be found by simply switching out A for T and G for C or vice versa.

The base-pairing rules also imply that the 5' end of one strand is complementary to the 3' end of the other strand and vice versa. The correct complementary sequence to 5'-ATTGCA-3' would thus be 5'-TGCAAT-3'.

Therefore, option B) 5'-TGCAAT-3' is the right answer.

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The sum of 3(3)/(8) and 6(1)/(2) is 5(5)/(8), which is a mixed number representing 5 whole units and 5/8 of another unit.

To find the sum of mixed numbers, we need to add the whole numbers and the fractions separately. Add the whole numbers: 3 + 6 = 9

Add the fractions: For the fractions 3/(8) and 1/(2), we need to find a common denominator. The least common multiple of 8 and 2 is 8.

Converting 3/(8) to have a denominator of 8:

3/(8) = (3 x 1)/(8 x 1) = 3/(8)

Converting 1/(2) to have a denominator of 8:

1/(2) = (1 x 4)/(2 x 4) = 4/(8)

Now, we can add the fractions:

3/(8) + 4/(8) = (3 + 4)/(8) = 7/(8)

Combine the whole numbers and fractions:

The whole numbers sum was 9 and the fractions sum was 7/(8). We can write this as a mixed number by dividing the numerator (7) by the denominator (8). The quotient is 0 with a remainder of 7. Therefore, the mixed number is 0(7)/(8), which can be simplified to 7/(8).

Therefore, sum of 3(3)/(8) and 6(1)/(2) is 5(5)/(8).

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Answer:

don't know

Explanation:

Thanks❤ have a nice day

Answer:

Liquid

Explanation:

Octane is a straight chain alkane composed of 8 carbon atoms. It has a role as a xenobiotic. N-octane is a colorless liquid with an odor of gasoline.

Answer:11.60%

Explanation:

\(Percent Error = \frac{Actual - Theoretical}{Actual} (100)\\\)

\(Percent Error = \frac{74.65-66.89}{66.89} (100) = 11.60%\)%

Higher atmospheric carbon dioxide concentrations could lead to an increase in global temperatures, which could potentially impact sea turtle populations.

Warmer temperatures could lead to an increase in the proportion of female sea turtles being hatched, as warmer incubation temperatures are more likely to result in female hatchlings. This could lead to a skewed sex ratio, as there may be fewer male turtles to mate with the female turtles.

In addition to affecting the sex ratio of sea turtle hatchlings, higher temperatures could also impact other aspects of their development, such as the timing of hatching and the success of hatchlings in reaching the ocean.

Changes in temperature could also impact the availability of food and nesting sites for sea turtles, which could further impact their population dynamics.

Overall, the impact of higher atmospheric carbon dioxide concentrations on sea turtle populations will depend on a variety of factors, including the magnitude and rate of temperature increase, as well as other environmental factors that could impact sea turtle development and survival.

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When potassium chloride (KCl) is dissolved in water, the temperature decreases because the energy required to separate the potassium (K) and chloride (Cl-) ions and the energy required to separate the water molecules is greater than the energy produced by the attractions between the K and Cl- ions.

When KCl dissolves in water, the K and Cl- ions are surrounded by water molecules. The process of dissolving involves breaking the ionic bonds between the K and Cl- ions and the formation of new ion-dipole interactions between the ions and water molecules. To separate the K and Cl- ions, energy must be supplied to overcome the attractive forces between them. Additionally, to separate the water molecules, energy is required to disrupt the intermolecular hydrogen bonding between the water molecules. The energy produced by the attractions between the K and Cl- ions is not sufficient to compensate for the energy required to break these bonds. As a result, energy is absorbed from the surroundings, which leads to a decrease in temperature. The endothermic process of dissolving KCl in water, which requires more energy input than energy released, causes the temperature of the solution to decrease.

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Answer:10

Explanation:

Multiply the volume by the density to get the mass.

Divide the mass by the molar mass to get the number of moles.

Answer:

12.66g

Explanation:

42.2% of 30.0g

=42.2/100 * 30.0

=0.422*30.0

12.66g

The answer fam is......... False

Explanation:

HCOOH (aq) + H2O (l) ⇋ HCOO- (aq) + H3O+ (aq)

acid 1 base 2 base 1 acid 2

Answer:

B. 8.8 x 10⁻¹²

Explanation:

In aqueous solution, silver chromate (Ag₂CrO₄) dissociates into ions as follows:

Ag₂CrO₄(s) ⇄ 2 Ag⁺(aq) + CrO₄²⁻(aq)

                       2s               s

So, the expression of the Ksp of Ag₂CrO₄ is derived from the concentrations of the ions at equilibrium raised by the stoichiometric coefficients:

Ksp = [Ag⁺]²[CrO₄²⁻] = (2s²)s = (4s²)s = 4s³

Since s = [Ag⁺] = 1.3 x 10⁻⁴ M, we calculate the Ksp as follows:

Ksp = 4s³= 4(1.3 x 10⁻⁴)³ = 8.79 x 10⁻¹² M

Therefore, the correct option is B. 8.8 x 10⁻¹²

Answer:

Explanation:

The density of a substance can be found by using the formula

\(density = \frac{mass}{volume} \\\)

From the question we have

\(denstity = \frac{100}{10} \\ \)

We have the final answer as

Hope this helps you

Answer:

thanks

Explanation: