The half life for the radioactive decay of potassium-40 to argon-40 is 1.26×109 years. Suppose nuclear chemical analysis shows that there is 0.359 mmol of argon-40 for every 1.000mmol of potassium-40 in a sample of rock. Calculate the age of the rock.

Answer:

33.8 g Solution

Explanation:

A chemistry student needs 15.0 g of methanol for an experiment. The concentration of ethanol in the solution is 44.4% w/w, that is, there are 44.4 g of methanol every 100 g of solution. The mass of solution that would contain 15.0 g of methanol is:

15.0 g Methanol × 100 g Solution/44.4 g Methanol = 33.8 g Solution

Since 33.8 g are required and 320. g are available, there is enough solution for the requirements.

Answer: The millimoles of potassium iodide the chemist has added to the flask is 522 millimoles.

Explanation:

Given: Volume of KI = 370.0 mL (1 mL = 0.001 L) = 0.37 L

Molarity of KI solution = 1.41 mol/L

Now, moles of KI (potassium iodide) is calculated as follows.

[tex]Moles = Volume \times Molarity \\= 0.37 L \times 1.41 M\\= 0.5217 mol[/tex]

Convert moles into millimoles as follows.

1 mol = 1000 millimoles

0.5217 mol = [tex]0.5217 mol \times \frac{1000 millimoles}{1 mol} = 521.7 millimoles[/tex]

This can be rounded off to the value 522 millimoles.

Thus, we can conclude that the millimoles of potassium iodide the chemist has added to the flask is 522 millimoles.

Answer:

A) 1.3 × 10⁻⁵ mol/L

Explanation:

Step 1: Write the balanced equation for the solution of AgCl

AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)

Step 2: Make an ICE Chart

        AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)

I                           0             0

C                        +S            +S

E                          S              S

If we replace the solubility (S) in the Ksp expression, we get,

Ksp = [Ag⁺] [Cl⁻] = S × S = S²

S = √Ksp = √1.8 × 10⁻¹⁰ = 1.3 × 10⁻⁵ mol/L

Answer:

Reactions involving the replacement of one atom or group of atoms. - Substitution reaction

Reactions involving removal of two atoms or groups from a molecule - Elimination reaction

Products show increased bond order between two adjacent atoms - Elimination reaction

Reactant requires presence of a π bond - Addition reaction

Product is the structural isomer of the reactant - Rearrangement reaction

Explanation:

When an atom or a group of atoms is replaced by another in a reaction, then such is a substitution reaction. A typical example is the halogenation of alkanes.

A reaction involving the removal of two atoms or groups from a molecule resulting in increased bond order of products is called an elimination reaction. A typical example of such is dehydrohalogenation of alkyl halides.

Any reaction that involves a pi bond is an addition reaction because a molecule is added across the pi bond. A typical example is hydrogenation of alkenes.

Rearrangement reactions yield isomers of a molecule. Rearrangement may involve alkyl or hydride shifts in molecules.

Reactions involving the replacement of one atom or group of atoms is substitution reaction, reactions involving removal of two atoms or groups from a molecule and products show increased bond order between two adjacent atoms is elimination reaction, reactant requires presence of a π bond in addition reaction and product is the structural isomer of the reactant is rearrangement reaction.

Chemical reactions are those reactions in which reactants undergoes through a variety of changes for the formation of new product.

Hence, classification of above points are done according to their characteristics.

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Answer:

Explanation:

When an electron moves from a lower energy level to a higher energy level, energy is absorbed by the atom. When an electron moves from a higher to a lower energy level, energy is released and photon is emitted.

this emitted photon is depicted as a small wave-packet being expelled by the atom in a well-defined direction.

Answer:it dissolves and evaporates

Explanation:

Answer:

Mixture of a Strong Acid and a Strong Base

On mixing a strong acid and strong base neutralization (pH = 7) takes place. The resulting solution may be an acid or base depending on the Concentration. Say, N1, V1 is the strength and volume of the strong acid and N2, V2 is the strength and volume of the strong base

Explanation:

Most introductory chemistry books will teach that the reaction between an acid and a base is called neutralization, and the products formed are water and a salt

Answer:

For (a): The moles of Ar is 16.94 moles

For (b): The moles of [tex]Cl_2[/tex] is 16.94 moles

For (c): The total number of moles in a tank is 23.47 moles

For (d): The mole fraction of Ar is 0.722

For (e): The mole fraction of [tex]Cl_2[/tex] is 0.278

For (f): The partial pressure of Ar is 2.888 atm

For (g): The partial pressure of [tex]Cl_2[/tex] is 1.112 atm

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of Ar = 675.5 g

Molar mass of Ar = 39.95 g/mol

Plugging values in equation 1:

[tex]\text{Moles of Ar}=\frac{675.5g}{39.95g/mol}=16.91 mol[/tex]

Given mass of [tex]Cl_2[/tex] = 465.0 g

Molar mass of [tex]Cl_2[/tex] = 70.9 g/mol

Plugging values in equation 1:

[tex]\text{Moles of }Cl_2=\frac{465.0g}{70.9g/mol}=6.56 mol[/tex]

Total moles of gas in the tank = [16.91 + 6.56] mol = 23.47 mol

Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:

[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex]        .....(2)

where n is the number of moles

Moles of Ar = 16.94 moles

Total moles of gas in the tank = 23.47 mol

Putting values in equation 2, we get:

[tex]\chi_{Ar}=\frac{16.94}{23.47}\\\\\chi_{Ar}=0.722[/tex]

Total mole fraction of the system is always 1

Mole fraction of [tex]Cl_2[/tex] = [1 - 0.722] = 0.278

Raoult's law is the law used to calculate the partial pressure of the individual gases present in the mixture.

The equation for Raoult's law follows:

[tex]p_A=\chi_A\times p_T[/tex]                  .....(3)

where [tex]p_A[/tex] is the partial pressure of component A in the mixture and [tex]p_T[/tex] is the total partial pressure of the mixture

We are given:

[tex]\chi_{Ar}=0.722\\p_T=4.00atm[/tex]

Putting values in equation 3, we get:

[tex]p_{Ar}=0.722\times 4.00atm\\\\p_{Ar}=2.888atm[/tex]

We are given:

[tex]\chi_{Cl_2}=0.278\\p_T=4.00atm[/tex]

Putting values in equation 3, we get:

[tex]p_{Cl_2}=0.278\times 4.00atm\\\\p_{Cl_2}=1.112atm[/tex]

Answer: The molarity of NaCl solution is 0.0489 M

Explanation:

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L. The formula used to calculate molarity:

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

We are given:

Given mass of NaCl = 0.8 g

Molar mass of NaCl = 58.44 g/mol

Volume of the solution = 280 mL

Putting values in equation 1, we get:

[tex]\text{Molarity of solution}=\frac{0.8\times 1000}{58.44\times 280}\\\\\text{Molarity of solution}=0.0489M[/tex]

Hence, the molarity of NaCl solution is 0.0489 M

Answer:

aasjajiakjka

Explanation:

Answer: Pair 1 has Mg and Sr, Pair 2 has Kr and Ne, Pair 3 has As and P.

Explanation:

A periodic table is a group of elements presented in a tabular form where elements are arranged in a series of 7 rows and 18 columns.

The vertical columns are known as groups and horizontal rows are known as periods.

The elements having similar chemical properties are arranged in one group.

Magnesium (Mg) is the 12th element of periodic table placed at Group 2 and Period 3

Strontium (Sr) is the 38th element of periodic table placed at Group 2 and Period 5

Krypton (Kr) is the 36th element of periodic table placed at Group 18 and Period 4

Neon (Ne) is the 10th element of periodic table placed at Group 18 and Period 2

Arsenic (As) is the 33rd element of periodic table placed at Group 15 and Period 4

Phosphorus (P) is the 15th element of periodic table placed at Group 15 and Period 3

As magnesium and strontium are present in the same group, they will have similar chemical properties. Similarly, krypton and neon will form the second pair. Likewise, arsenic and phosphorus will form a pair.

Hence, Pair 1 has Mg and Sr, Pair 2 has Kr and Ne, Pair 3 has As and P.

Answer:

bleh

Explanation:

Answer:

43.5

Explanation:

Hope that helps

The answer ( 13 and 8 )

x²=5²+12²

x²=25+144

x²=169

x=13

x²=5²+6²

x²=25+36

x²=61

x=7.8

x=8

Answer:

A 1 liter volumetric flask should be used.

Explanation:

First we convert 166.00 g of KI into moles, using its molar mass:

Molar mass of KI = Molar mass of K + Molar mass of I = 166 g/mol

Then we calculate the required volume, using the definition of molarity:

Liters = moles / molarity

Answer:

Magnesium reacts with dilute hydrochloric acid in a conical flask which is ... One student can add the magnesium ribbon to the acid and stopper the flask, ... 50 cm3 of 1M hydrochloric acid is a six-fold excess of acid.

Answer:

See explanation.

Explanation:

Hello there!

In this case, since this problem  is about gas laws, more specifically about the Gay-Lussac's one since the volume is said to be constant, we can use the following equation for its solution for the final pressure, P2:

[tex]\frac{P_2}{T_2} = \frac{P_1}{T_1}[/tex]

[tex]P_2= \frac{P_1T_2}{T_1}\\\\P_2 =\frac{12.0atm*450K}{300K}\\\\P_2= 18.0atm[/tex]

Thus, we fill in the table as follows:

                           Initial        Final

Pressure           12.0 atm     18.0 atm

Volume                4.0 L         4.0 L

Temperature      300K         450K

Regards!

Answer: The mass of [tex](NH_4)_2SO_4[/tex] produced is 9910.5 g

Explanation:

Molarity is calculated by using the equation:

[tex]\text{Molarity}=\frac{\text{Moles}}{\text{Volume}}[/tex] ......(1)  

Molarity of [tex]H_2SO_4[/tex] = 3.0 M

Volume of solution = 25.0 L

Putting values in equation 1, we get:

[tex]\text{Moles of }H_2SO_4=(3.0mol/L\times 25.0L)=75mol[/tex]

The ideal gas equation is given as:

[tex]PV=nRT[/tex] .......(2)

where,

P = pressure of the gas = 0.68 atm

V = volume of gas = [tex]3.1\times 10^3L[/tex]

n = number of moles of gas = ? moles

R = Gas constant = 0.0821 L.atm/mol.K

T = temperature of the gas = 298 K

Putting values in equation 2, we get:

[tex]0.68atm\times 3.1\times 10^3L=n\times 0.0821L.atm/mol.K\times 298K\\\\n=\frac{0.68\times 3.1\times 10^3}{0.0821\times 298}=86.16mol[/tex]

For the given chemical equation:

[tex]NH_3(g)+H_2SO_4(aq)\rightarrow (NH_4)_2SO_4(aq)[/tex]

By stoichiometry of the reaction:

If 1 mole of [tex]H_2SO_4[/tex] reacts with 1 mole of [tex]NH_3[/tex]

So, 75 moles of [tex]H_2SO_4[/tex] will react with = [tex]\frac{1}{1}\times 75=75mol[/tex] of [tex]NH_3[/tex]

As the given amount of [tex]NH_3[/tex] is more than the required amount. Thus, it is present in excess and is considered as an excess reagent

Thus, [tex]H_2SO_4[/tex] is considered a limiting reagent because it limits the formation of the product.

By the stoichiometry of the reaction:

If 1 mole of [tex]H_2SO_4[/tex] produces 1 mole of [tex](NH_4)_2SO_4[/tex]

So, 75 moles of [tex]H_2SO_4[/tex] will produce = [tex]\frac{1}{1}\times 75=75mol[/tex] of [tex](NH_4)_2SO_4[/tex]

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

We know, molar mass of [tex](NH_4)_2SO_4[/tex] = 132.14 g/mol

Putting values in above equation, we get:

[tex]\text{Mass of }(NH_4)_2SO_4=(75mol\times 132.14g/mol)=9910.5g[/tex]

Hence, the mass of [tex](NH_4)_2SO_4[/tex] produced is 9910.5 g

Answer:

0.375mL of solution of nalorphine must be injected

Explanation:

A solution of 0.40% (w/v) contains 0.40g of solute (In this case, nalorphine), in 100mL of solution. To obtain 1.5mg of nalorphine = 1.5x10⁻³g of nalorphine are needed:

1.5x10⁻³g * (100mL / 0.40g) =

Answer: The %v/v of the given KCl solution is 7.6%.

Explanation:

Given: Volume of solute = [tex]4.6 \times 10^{1} ml[/tex]

Volume of solution = [tex]6.0 \times 10^{-1} g/ml[/tex]

Formula used to calculate %v/v is as follows.

[tex]\frac{volume of solute}{volume of solution} \times 100[/tex]

Substitute the values into above formula as follows.

[tex]\frac{volume of solute}{volume of solution} \times 100\\\frac{4.6 \times 10^{1}}{6.0 \times 10^{-1}} \times 100\\= 7.6[/tex]

Thus. we can conclude that the %v/v of the given KCl solution is 7.6%.

Answer:

c it does not change the energy state

Explanation:

Answer:

Mg will be the limiting reagent.

Explanation:

The balanced reaction is:

Mg + 2 HCl → MgCl₂ + H₂

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

Being the molar mass of each compound:

By reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

0.0350 g of Mg is reacted with 10.00 mL (equal to 0.01 L) of 6 M HCl.

Molarity being the number of moles of solute that are dissolved in a certain volume, expressed as:

[tex]Molarity=\frac{number of moles of solute}{volume}[/tex]

in units [tex]\frac{moles}{liter}[/tex]

then, the number of moles of HCl that react is:

[tex]6 M=\frac{number of moles of HCl}{0.01 L}[/tex]

number of moles of HCl= 6 M*0.01 L

number of moles of HCl= 0.06 moles

Then you can apply the following rule of three: if by stoichiometry 2 moles of HCl react with 24.3 grams of Mg, 0.06 moles of HCl react with how much mass of Mg?

[tex]mass of Mg=\frac{0.06 moles of HCl* 24.3 grams of Mg}{2 moles of HCl}[/tex]

mass of Mg= 0.729 grams

But 0.729 grams of Mg are not available, 0.0350 grams are available. Since you have less mass than you need to react with 0.06 moles of HCl, Mg will be the limiting reagent.

The limiting reactant in the reaction is Magnesium (Mg)

From the question,

We are to determine the limiting reactant in the reaction.

The given balanced chemical equation for the reaction is

Mg(s) + 2HCl(aq) → MgCl₂(aq) + H₂(g)

This means

1 mole of Mg is required to react completely with 2 moles of HCl

Now, we will determine the number of moles of each reactant present

Mass = 0.0350 g

Using the formula

[tex]Number\ of\ moles = \frac{Mass}{Atomic\ mass}[/tex]

Atomic mass of Mg = 24.305 g/mol

∴ Number of moles of Mg present = [tex]\frac{0.0350}{24.305}[/tex]

Number of moles of Mg present = 0.00144 mole

Concentration = 6M

Volume = 10.00 mL = 0.01 L

Using the formula

Number of moles = Concentration × Volume

∴ Number of moles HCl present = 6 × 0.01

Number of moles HCl present = 0.06 mole

Since,

1 mole of Mg is required to react completely with 2 moles of HCl

Then

0.00144 mole of Mg is required to react completely with 2×0.00144 mole of HCl

2×0.00144 = 0.00288

∴ The number of moles of HCl required to react completely with the Mg is 0.00288 mole

Since the number of moles of HCl present is more than 0.00288 mole, then HCl is the excess reactant and Mg is the limiting reactant.

Hence, the limiting reactant in the reaction is Magnesium (Mg)

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When we pre-weigh a glass vial to hold our sample and find its mass to be 5.010 g. Then we add our sample to the vial and reweigh it on the same balance and find that the mass has increased to 6.130 g. The mass of the sample in grams is 1.12 g.

Avogadro's number is the number of units in one mole of any substance and equals to 6.02214076 × 10²³. The units can be electrons, atoms, ions, or molecules.

No. of moles is defined as a particular no. of particles that we can calculate with the help of Avogadro’s number.

Mass of a particular product is also find out by stoichiometry of a reaction as per the no. of mole given in the reaction.

Mass is generally can be represented by units like Kg, g etc.

Given,

weigh of glass vial = 5.010 g

weigh of glass vial with sample = 6.130 g

Therefore, When we pre-weigh a glass vial to hold our sample and find its mass to be 5.010 g. Then we add our sample to the vial and reweigh it on the same balance and find that the mass has increased to 6.130 g. The mass of the sample in grams is 1.12 g.

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Answer:

hi I used your code you got it

Answer:

For the neutralization reaction between pyridine and propanoic acid, draw curved arrows to indicate the direction of electron flow.

Draw curved arrows to show the movement of electrons in this step of the mechanism.

Explanation:

According to Bronsted acid-base theory, an acid is a substance which is a proton donor.

Base is the proton acceptor.

In the given example, acid is propanoic acid and it loses the proton.

Pyridine is the base and it accepts the proton from propanoic acid.

The entire reaction is shown below:

Answer: The correct option is B) oxidized

Explanation:

Redox reaction is defined as the reaction in which oxidation and reduction take place simultaneously.

The oxidation reaction is defined as the reaction in which a chemical species loses electrons in a chemical reaction. It occurs when the oxidation number of a species increases.

A reduction reaction is defined as the reaction in which a chemical species gains electrons in a chemical reaction. It occurs when the oxidation number of a species decreases.

For the given chemical reaction:

[tex]Zn+H_2SO_4+S\rightarrow ZnSO_4+H_2[/tex]

On the reactant side:

Oxidation number of H = +1

Oxidation number of Zn = 0

Oxidation number of S = +6

Oxidation number of O = -2

On the product side:

Oxidation number of H = 0

Oxidation number of Zn = +2

Oxidation number of S = +6

Oxidation number of O = -2

As the oxidation number of Zn is increasing from 0 to +2. Thus, it is getting oxidized. Similarly, the oxidation number of H is decreasing from +1 to 0. Thus, it is getting reduced.

Hence, the correct option is B) oxidized

The question is incomplete, the complete question is:

A 7.00 L tank at [tex]21.4^oC[/tex] is filled with 5.43 g of sulfur hexafluoride gas and 14.2 g of sulfur tetrafluoride gas. You can assume both gases behave as ideal gases under these conditions. Calculate the mole fraction and partial pressure of each gas. Round each of your answers to significant digits.

Answer: The mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass.  The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of sulfur hexafluoride = 5.43 g

Molar mass of sulfur hexafluoride = 146.06 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of sulfur hexafluoride}=\frac{5.43g}{146.06g/mol}=0.0372mol[/tex]

Given mass of sulfur tetrafluoride = 14.2 g

Molar mass of sulfur tetrafluoride = 108.07 g/mol

Putting values in equation 1, we get:

[tex]\text{Moles of sulfur tetrafluoride }=\frac{14.2g}{108.07g/mol}=0.1314mol[/tex]

Total moles of gas in the tank = [0.0372+ 0.1314] mol = 0.1686 mol

Mole fraction is defined as the moles of a component present in the total moles of a solution. It is given by the equation:

[tex]\chi_A=\frac{n_A}{n_A+n_B}[/tex] .....(2)

where n is the number of moles

Putting values in equation 2, we get:

[tex]\chi_{SF_6}=\frac{0.0372}{0.1686}=0.221[/tex]

[tex]\chi_{SF_4}=\frac{0.1314}{0.1686}=0.779[/tex]

Hence, the mole fraction of sulfur hexafluoride is 0.221 and that of sulfur tetrafluoride is 0.779

Answer:

2.11×10²³ atoms.

Explanation:

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

Mass of Ne = 7 g

Number of atoms =?

Recall:

1 mole of Ne = 6.02×10²³ atoms

1 mole of Ne = 20 g

Thus,

20 g of Ne = 6.02×10²³ atoms

Finally, we shall determine the number of atoms in 7 g of Ne. This can be obtained as follow:

20 g of Ne = 6.02×10²³ atoms

Therefore,

7 g of Ne = (7 × 6.02×10²³) / 20

7 g of Ne = 2.11×10²³ atoms

Thus, 7 g of Ne contains 2.11×10²³ atoms.

Answer:

Explanation:

[H+] = 0.1x0.03x2 + 0.2x0.03 = 0.012 mol

[OH-] = 0.001x0.05x2 = 0.0001 mol

=> [H+] dư = 0.012 - 0.0001 =0.0119 mol

pH = -log[H+] = 1.92