5.
A 120.0 g sample of Thallium-208 decays. How much of the sample will remain after 3 half lifest​

Explanation:

[tex]\text{number of moles}=\frac{\text{given mass}}{\text{molar mass}}[/tex]

For [tex]NH_{3},[/tex]

[tex]\text{given mass}=3g[/tex]

[tex]\text{molar mass}=14+3=17g[/tex]

[tex]n_{NH_{3}}=\frac{3}{17}=0.176[/tex]

For [tex]HCl,[/tex]

[tex]\text{given mass}=5g[/tex]

[tex]\text{molar mass}=1+35.5=36.5g[/tex]

[tex]n_{HCl}=\frac{5}{36.5}=0.136[/tex]

The reaction between [tex]NH_{3}[/tex] and [tex]HCl[/tex] is

[tex]NH_{3}+HCl[/tex]→[tex]NH_{4}Cl[/tex]

So,one mole of [tex]NH_{3}[/tex] requires one mole of [tex]HCl[/tex]

[tex]0.176[/tex] moles of [tex]NH_{3}[/tex] requires [tex]0.176[/tex] moles of [tex]HCl[/tex]

But there are only [tex]0.136[/tex] moles of [tex]HCl[/tex] available.

[tex]HCl[/tex] will be consumed first.

So,[tex]HCl[/tex] is the limiting reagent.

To convert 4.82 mmol of diphenylmethanol to grams, calculate the molar mass of C13H12O to be 184.32 g/mol. Then, multiply 4.82 mmol by the molar mass and divide by 1000 mmol/mol to get 0.8886 grams.

To convert 4.82 mmol of diphenylmethanol (C13H12O) to grams, you first need to calculate the molar mass of diphenylmethanol. The molar mass is calculated by the sum of the atomic weights of each atom in the molecular formula. The molecular weights are approximately: Carbon (C) = 12.01 g/mol, Hydrogen (H) = 1.008 g/mol, and Oxygen (O) = 16.00 g/mol. Thus, the molar mass of C13H12O is (13x12.01 g/mol) + (12x1.008 g/mol) + (16.00 g/mol) = 184.32 g/mol.

Next, use the conversion factor that relates millimoles to grams using the molar mass:

4.82 mmol C13H12O x (184.32 g/mol) / (1000 mmol/mol) = 0.8886 g C13H12O

So, 4.82 mmol of diphenylmethanol is equivalent to 0.8886 grams.

Answer:

0.326338 kcal

Explanation:

Data given:

Value in Joules = 1365.4 joules

Value in Kilocalories (kcal) =  to find

Solution:

Joule and Kilocalori both are the unit of energy

Relation of kilocalori

                   1 joule = 0.000239 kcal

so now to find

1365.4 joules equals to how much kilocalories

if

                                 1 joule = 0.000239 kcal

then                1365.4 joules = ? Kilocalories

by cross multiplication

          1 joule x ? Kilocalories = 0.000239 kcal x 1365.4 joules

By rearranging

           Kilocalories = 0.000239 kcal x 1365.4 joules / 1 joule

         Kilocalories = 0.000239 kcal x 1365.4 joules / 1 joule

         Kilocalories = 0.32633 kcal

So

         1365.4 joules = 0.32633 kcal  

[tex]1365.4 \ joules[/tex] is approximately [tex]0.3264\ kilocalories.[/tex]

To convert energy from joules to kilocalories, we use the conversion factor:

[tex]\[ 1 \, \text{kilocalorie} = 4184 \, \text{joules} \][/tex]

Given:

[tex]\[ 1365.4 \, \text{joules} \][/tex]

We convert joules to kilocalories as follows:

[tex]\[ \text{kilocalories} = \frac{\text{joules}}{\text{joules per kilocalorie}} = \frac{1365.4 \, \text{joules}}{4184 \, \text{joules per kilocalorie}} \][/tex]

Perform the calculation:

[tex]\[ \text{kilocalories} = \frac{1365.4}{4184} \][/tex]

[tex]\[ \text{kilocalories} = 0.3264 \][/tex]

Answer:

individual ancient shark vertebra

Explanation:

it ask for a body fossil and that is the only body fossil

One of the example that falls under classification of body fossil is C:

individual ancient shark vertebra

The main types of fossil are:

Most of the  body fossils usually have a hard parts these part could be

Therefore, option C is right

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Answer:

Q and R are most likely to form an ionic bond.

Explanation:

Ionic bond is formed between two elements which have huge difference in their electronegativities.

     According to the given question the electronegativity difference of QR is greater than that of PQ, RS and SP.

   From this point of view it can be stated that Q and R are most likely to form an ionic bond.

Answer:

Q and R

Explanation:

Answer:

Therefore F ∠ 2.5N

Explanation:

Definition of Work:

It is the amount of energy transferred.

Mathematical expression:

W = F × d

By taking the friction into count it will define as:

Input work = work against friction ×  output work

No we will put the values:

25 J = w + 10 m

j = kg m²/s²

25 kg m²/s² =  w + 10 m

when friction is exist then w > 0

25 kg m²/s² - 10 m  > 0

15 N > 0

Therefore F ∠ 2.5N

Answer:

d) Chlorine

Explanation:

when an atom form ion its atomic radius changed from neutral atomic radius.

if the atom form cation its atomic radius is smaller than neutral atomic radius.

If atom form anion its anionic radius is larger than the neutral atomic radius.

The reason is that when electron is remove energy shell deduced so cation get smaller ionic radii while in case of anion electron is added and size increase.

In given list of elements potassium, zinc and chromium form cation while chlorine form anion.

That's why its ionic radius will larger than atomic radius.

The element with an ion that has a larger radius than its atomic radius is potassium (K).

Based on the information provided, the ion with a radius larger than its atomic radius is K (potassium). This is because potassium loses an electron to form a cation (K+), which has a larger radius than its neutral atomic form. The loss of one electron reduces the attractive force between the electrons and the nucleus, causing the electron cloud to expand, resulting in a larger radius.

Answer:

a

Explanation:

Volume

Answer:

ester C6H5CH2OC2H5 is formed.

Explanation:

C6H5CH2OH + C2H5OH ---> C6H5CH2OC2H5 + H2O

Esterification reaction of benzoic acid with ethanol in presence of concentrated sulfuric acid​ is C₆H₅CH₂OH + C₂H₅OH → C₆H₅CH₂OC₂H₅ + H₂O.

Esterification is the process of combining an organic acid (RCOOH) with an alcohol (ROH) to produce an ester (RCOOR) and water, or a chemical reaction that produces at least one ester product. Ester is formed by the esterification of an alcohol and a carboxylic acid.

An acid catalyst, typically sulfuric acid, is added to speed up the reaction while also acting as a dehydrating agent.

Benzoic acid (a carboxylic acid) is esterified with methanol (an alcohol) in the presence of sulfuric acid (an acid catalyst) in this Fischer esterification reaction to produce methyl benzoate (an ester).

Thus, C₆H₅CH₂OH + C₂H₅OH → C₆H₅CH₂OC₂H₅ + H₂O.

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Answer:

Mg+

Explanation:

Cation is an ion that has lost its electron(s).

So, it has a positive charge.

Any ion with a positive charge (superscript has a + sign) is a cation.

Final answer:

A Lucas reagent is a mixture of zinc chloride and concentrated hydrochloric acid that is used to distinguish between primary, secondary, and tertiary alcohols.

Explanation:

A Lucas reagent is a mixture of zinc chloride (ZnCl2) and concentrated hydrochloric acid (HCl) that is used to distinguish between primary, secondary, and tertiary alcohols.

When the Lucas reagent is added to an alcohol, a reaction occurs where a cloudy precipitate of alkyl chlorides is formed. The rate at which the precipitate forms depends on the type of alcohol:

Answer:

C = Electrons are won and lost.

Explanation:

The oxidation reduction reactions are called redox reaction. These reactions are take place by gaining and losing the electrons and oxidation state of elements are changed.

Oxidation:

Oxidation involve the removal of electrons and oxidation state of atom of an element is increased.

Reduction:

Reduction involve the gain of electron and oxidation number is decreased.

Consider the following reactions.

4KI + 2CuCl₂  →   2CuI  + I₂  + 4KCl

the oxidation state of copper is changed from +2 to +1 so copper get reduced.

CO + H₂O   →  CO₂ + H₂

the oxidation state of carbon is +2 on reactant  side and on product side it becomes  +4 so carbon get oxidized.

Na₂CO₃ + H₃PO₄  →  Na₂HPO₄ + CO₂ + H₂O

The oxidation state of carbon on reactant side is +4. while on product side is  also +4 so it neither oxidized nor reduced.

H₂S + 2NaOH → Na₂S + 2H₂O

The oxidation sate of sulfur is -2 on reactant side and in product side it is also -2 so it neither oxidized nor reduced.

Oxidizing agents:

Oxidizing agents oxidize the other elements and itself gets reduced.

Reducing agents:

Reducing agents reduced the other element are it self gets oxidized.

Its molecule contains one oxygen and two hydrogen atoms.

Explanation:

Water is a chemical substance with the chemical formula H2O. Water is a chemical substance with the chemical formula H2O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds.

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Similar rocks found on different continents, Mountains created by colliding continents, Evidence of glaciers in unexpected places are the evidences to support the idea that all the continents were once joined together.

Option D, All the above.

Earth did not have seven continents but only one, nearly 300 million years ago. There was one "massive super continent", called the Pangaea. The Pangaea was also surrounded by the ocean named panthalassa. Experts say that the formation of the seven continents happened due to the movement in the tectonic plates.

Similar kinds of rocks were found on different continents, it is also believed that the Aps were formed due to the separation of continents, coal deposits of the same constituents were also found on different continents.

Answer:

all of the above

Explanation:

Answer:

[tex](_{1} ^ {1}\textrm{H})[/tex]  is the correct choice that is option A.

Explanation:

An electron has [tex]\frac{1}{1836}[/tex] times the mass of a proton, but an equal and opposite negative charge.

Lets [tex]_{A}^{Z}\textrm{X}[/tex] is any element represented here.

Where [tex]Z[/tex] is the number of protons as well as its atomic number.

And

[tex]A[/tex] is the mass number which is the number of protons and neutrons in any atom.

Note: We know that Hydrogen [tex](_{1} ^ {1}\textrm{H})[/tex] is devoid of neutron,so number of neutrons in a Hydrogen atom is zero.

Then

[tex](_{1} ^ {1}\textrm{H})[/tex] is also a representation of single proton.

So [tex](_{1} ^ {1}\textrm{H})[/tex] is the right choice that is option A.

The mass of an electron is approximately 1/1836 times the mass of a proton.

The mass of an electron is approximately 1/1836 times the mass of a proton (choice B). This means that the mass of the electron is much smaller compared to the mass of the proton. For example, in a hydrogen atom, which consists of just one proton and one electron, the mass of the proton is about 1836 times greater than the mass of the electron.

Answer:

The Venus flytrap consumes its food in the form of flies and other small insects not through the roots as other plants

Explanation:

Answer:

The thing about the venus fly trap which makes it so unique and are known for is its ability to digest insects.

Explanation:

The thing about the venus fly trap which makes it so unique and are known for is its ability to digest insects. In its name "fly trap" which are commonly house plants implies the ability of trapping insects for its nutrional value

Answer:

Electronic Configuration of calcium ion: Ca²⁺

1s², 2s², 2p⁶, 3s², 3p⁶

Explanation:

Calcium belong to group IIA and known as alkaline earth metals.

Electronic Configuration of calcium atom: ²⁰Ca

1s², 2s², 2p⁶, 3s², 3p⁶, 4s²

When calcium ion is form it loses two electron and have 2+ charge on it.

and have total of 18 electrons

So,

Electronic Configuration of calcium ion: Ca²⁺

the last filled orbital will be 3p⁶

1s², 2s², 2p⁶, 3s², 3p⁶

There are five significant figures in the measurement 0.023040 cm.

To determine the number of significant figures in a given measurement, one must follow these rules:

1. Non-zero digits are always significant. In the measurement 0.023040 cm, the digits 2, 3, and 4 are non-zero and thus significant.

2. Zeros between non-zero digits are significant. Here, the zero between the 3 and the 4 is significant because it is sandwiched between two non-zero digits.

3. Leading zeros, which are zeros before the first non-zero digit in a number less than one, are not significant. In this case, the two zeros after the decimal point and before the 2 are leading zeros and are not significant.

4. Trailing zeros, which are zeros at the end of a number, are significant if the number has a decimal point. In the measurement 0.023040 cm, the zero at the end is after the decimal point and is therefore significant.

Applying these rules, we count the significant figures in 0.023040 cm as follows:

- The first two zeros after the decimal point are not significant (leading zeros).

- The digit 2 is significant.

- The digit 3 is significant.

- The zero between the 3 and the 4 is significant (it is between two non-zero digits).

- The digit 4 is significant.

- The last zero is significant (trailing zero after the decimal point).

Therefore, the measurement 0.023040 cm has five significant figures.

Answer:

D. bromine (Br)

Explanation:

Bromine is an element of halogen group.

Halogens, or "salt-formers," are located in group 17 of the periodic table. The halogens have  the following properties:

1) They have low melting points and low boiling points.

2) They exist as diatomic molecules in the gas phase.

3) They have seven electrons in their outermost shell, which means they have seven valence

electrons.

4) They are highly reactive nonmetals.

5) They tend to gain electrons and form negative ions.

Thus the given properties are of Bromine.

Answer:

Titan which orbits Saturn

Explanation:

Saturn's Titan is the only moon known to have a significant atmosphere, composed mainly of nitrogen with organic particles and methane lakes on its surface.

The only satellite known to have an atmosphere in the planet it orbits is Titan, the largest moon of Saturn. Titan has a substantial atmosphere composed mainly of nitrogen. It is the only moon in the outer solar system with a significant atmosphere, and its atmosphere is even denser than Earth's. The atmosphere of Titan is of great interest to scientists because it contains organic particles and may provide clues to the early stages of life formation on Earth.

The only known satellite in the solar system with a substantial atmosphere is Saturn's Titan. Titan is unique among moons in that it possesses a dense atmosphere filled with organic particles. This atmosphere is primarily composed of nitrogen, similar to Earth's, but with temperatures too low to allow for carbon dioxide or water vapor, resulting in nitrogen being the dominant gas. The atmosphere on Titan is of great interest to scientists because it may provide clues to the early stages of how life formed on Earth. The Cassini spacecraft and the Huygens probe provided valuable data on Titan's composition, including the discovery of methane lakes on its surface.

Answer:

[tex]Zn^{0} --->Zn^{2+} +2e^{-}[/tex]

Explanation:

[tex]Zn^{0} --->Zn^{2+} +2e^{-}[/tex]

Answer:

If anything but H2O were found, it would be evidence of a chemical change. Therefore, 4 is the only viable evidence that it was a physical change of H2O liquid to H2O gas.

Answer:

4-[tex]H_{2}O_{(g)}[/tex]

Explanation:

Initially, the beaker contains distilled water which is liquid water at room temperature. When the beaker was placed on a hot plate and heat energy was applied the temperature of the system increases gradually until the boiling point was reached. Water generally boils at 100°C and at this temperature, liquid water changes to vapor or gas. In addition, liquid water and steam or water vapor are in equilibrium. Therefore, the presence of water vapor ([tex]H_{2}O_{(g)}[/tex]) indicates that the process is a physical change.

Answer:

13. Na  14. Ne. 15. U. 16. Ca. 17. C. l 18. O.  19. Cl. 20. Si  21. U  22. N.

23. Na 24. Ne. 25. U 26. Sc. 27. N 28. O 29. Cl 30. Si 31. U 32. N.

Explanation:

The general trend as you go to the right in any one period is for the size to decrease.

The general trend is that the size increases as you go down a Group.

The general trend as you go from the bottom left to the top right is a decrease in size.

Ionization energy increases as we move to the right in a period.

It decreases as we move down a group.

Going from the bottom left to top right - the ionization increases.

Answer:

The line drawn through points D and E.

Explanation:

Y is a horizontal line and D and E are both on the same line. If a line were drawn it would be within the Y plane.

Answer:

B. The line that can be drawn through points D and E is contained in plane Y.

Explanation:

The correct answer to the question is Option 2. Br

Electronegativity is simply defined as the ability of an atom to attract electron(s)

Non metals are more electronegative than metals.

Krypton, Kr is a group 18 element which have completely filled outermost shell. They do not involve in bond formation.

Calcium, Ca and Barium, Ba are group 2 metals. They form bond by losing their 2 valence electrons.

Bromine, Br is a group 17 element which have 7 valence electrons. It is difficult for Br to lose its valence electron(s) and as such, it will form bond by either gaining 1 electron or sharing 1 electron.

With the above information, we can conclude that Option 2. Br gives the correct answer to the question.

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Answer:

Balanced

Explanation:

2 Carbons per side

4 Hydrogens per side

3 Oxygen per side

1 Iron per side

Answer:

Balanced

Explanation:

For an equation to be balanced, the number of atoms of each element on the lefthand side and right hand side of the reaction equation must be exactly the same.

There are four hydrogen atoms on each side

There is one carbon atom on each side

There are three oxygen atoms on each side

There is one iron atom on each side.

This is how to know a balanced chemical reaction equation.

Answer:

The temperature range in the Mesosphere 15 degrees Celsius (5 degrees Fahrenheit) to negative 120 degrees Celsius (negative 184 degrees Fahrenheit)

Explanation:

The mesosphere lies above the stratosphere and extends over the Earth's surface to 85 kilometers (53 miles). The temperature at the mesosphere limit drops from negative 15 degrees Celsius (5 degrees Fahrenheit) to negative 120 degrees Celsius (negative 184 degrees Fahrenheit) at the base of the thermosphere.

Meteors vaporize in mesosphere, giving metallic ions a higher concentration than other layers of atmosphere.

Final answer:

The temperature in the mesosphere ranges from about 0°C at its lower boundary to as low as -100°C at the mesopause, its upper boundary. The mesosphere's low temperatures are due to its very thin air and lack of water vapor and ozone to absorb heat from the sun.

Explanation:

The temperature range in the mesosphere varies significantly with altitude. At the lower boundary, directly above the stratosphere (starting around 50 km above Earth's surface), temperatures can be around 0°C. As altitude increases within the mesosphere, temperatures drop sharply, reaching the mesosphere's lowest temperatures at the mesopause, which lies at the top of the mesosphere, around 85 km above the surface. Here, temperatures can plunge to as low as -100°C (-148°F).

The mesosphere is warmed from the bottom by the stratosphere below. The air in the mesosphere is very thin, and its density is approximately 1/1000th of that at the surface, which makes this atmospheric layer quite cold. This temperature decrease with altitude is due to the minimal amounts of water vapor and ozone that would otherwise help to absorb the sun's rays and heat the air.

Final answer:

Dmitri Mendeleev is credited with creating the first recognized periodic table of elements in 1869, which included predictions for undiscovered elements, making it a groundbreaking contribution to chemistry.

Explanation:

The answer to the student's question is a. True. Dmitri Mendeleev is widely credited with creating the first periodic table of the elements in 1869. This early version of the periodic table organized elements by increasing atomic mass and showcased periodic trends. Mendeleev also boldly left gaps in his table for undiscovered elements, predictively detailing their possible properties, many of which were later confirmed with the discovery of elements like gallium and germanium. While German chemist Lothar Meyer also published a similar table around the same time, Mendeleev's periodic table is generally recognized as more significant due to its predictive nature and earlier publication.

Answer:

A.   The new molarity of the diluted solution is 1.0176 M

B.   The new molarity of the diluted solution is 0.9947  M

C.   20 mL of volume is required to prepare 100ml of 1 M NaOH

Explanation:

Part A:

___________

This problem will be solved by using the following formula

                               M₁V₁ =  M₂V₂                        (1)

Given Data:

Initial Molarity of Solution M₁ = 3.24 M

Initial volume V₁ = 1.25 L

Initial volume V₂ = 3.98 L

Final Molarity M₂= ?

Put the values in formula 1

                          3.24 M x 1.25 L = M₂ x 3.98 L

By Rearranging

                         M₂  =  3.24 M x 1.25 L / 3.98 L

                         M₂  =  4.05 / 3.98

                          M₂  =  1.0176 M

The new molarity of the diluted solution is 1.0176 M

_________________

Part B:

This problem will be solved by using the following formula

                               M₁V₁ =  M₂V₂                        (1.1)

Given Data:

Initial Molarity of Solution M₁ = 7.0 M

Initial volume V₁ = 270 mL

As the initial volume is in ml and final volume in Litre (L)

So we have to convert mL to L

       1000ml= 1L

       270 ml = ? L

       1 x 270/ 1000 = 0.27 L

So

Initial volume V₁ = 0.27 L

Initial volume V₂ = 1.9 L

Final Molarity M₂= ?

Put the values in formula 1.1

                                               M₁V₁ =  M₂V₂  

                            7.0 M x 0.27 L = M₂ x 1.9 L

By Rearranging

                         M₂  =    7.0 M x 0.27 L / 1.9 L

                         M₂  =  1.89 / 1.9

                          M₂  =  0.9947 M

The new molarity of the diluted solution is 0.9947  M

_________________

Part 3

This problem will be solved by using the following formula

                               M₁V₁ =  M₂V₂                        (1.2)

Given Data:

Initial Molarity of Solution M₁ = 5 M

Initial volume V₁ = ? mL

Initial volume V₂ =  100 mL

Final Molarity M₂= 1 M

Put the values in formula 1.2

                                               M₁V₁ =  M₂V₂  

                            5 M x V₁ = 1 M x 100 mL

By Rearranging

                         V₁  =   1 M x 100 mL/ 5 M

                         V₁  =   100 / 5

                          V₁  =   20

20 mL of volume is required to prepare 100ml of 1 M NaOH

Answer:

V = 6.17 L

Explanation:

Given data:

Volume = ?

Number of moles = 0.382 mol

Pressure = 1.50 atm

Temperature = 295 k

R = 0.0821 L. atm. /mol. k

Solution:

According to ideal gas equation:

PV= nRT

V = nRT/P

V = 0.382 mol × 0.0821 L. atm. /mol. k ×295 k / 1.50 atm

V = 9.252  L. atm.  / 1.50 atm

V = 6.17 L

Final answer:

Using the ideal gas law, the volume of 0.382 moles of hydrogen gas at 1.50 atmospheres pressure and 295 K is approximately 6.17 L.

Explanation:

Using the ideal gas law, PV = nRT, we can calculate the volume of 0.382 moles of hydrogen gas at 1.50 atmospheres pressure and 295 K temperature. where T is the temperature, R is the ideal gas constant, n is the number of moles, V is the volume, and P is the pressure.

The provided values are: P = 1.50 atm, n = 0.382 moles, R = 0.0821 L•atm/mol•K, and T = 295 K. When we enter these numbers into the ideal gas law, we obtain:
V = nRT/PV = (0.382 mol) × (0.0821 L•atm/mol•K) × (295 K) / (1.50 atm)

Calculating this, we find the volume (V) of hydrogen gas:

V ≈ 6.17 L