how many moles in 1.505x10^23 Na atoms

Answers

Answer 1

Answer:

The answer is 0.25 moles

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question

N = 1.505 × 10²³ Na atoms

We have

[tex]n = \frac{1.505 \times {10}^{23} }{6.02 \times {10}^{23} } = \frac{1}{4} \\ [/tex]

We have the final answer as

0.25 moles

Hope this helps you


Related Questions

Galium is a metal that can melt in your hand at 302.93 k. what is the temperature in celcius ?

Answers

Explanation:

subtract it into 273.15to convert it in to celcius

Given that one mole occupies 22.4 L at STP, show that R = .082 (atm * L)/(mol*K)

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You’re going to use the ideal gas law which is pv=nrt. STP is standard temperature and pressure. Standard temp is 273.15 K and standard pressure is 1 atm.

WHAT IS A NEWTON!! specifically the definition!!!!

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Answer:

Explanation:

the SI unit of force. It is equal to the force that would give a mass of one kilogram an acceleration of one meter per second per second, and is equivalent to 100,000 dynes.

please help me :( What is the correct ratio of carbon to hydrogen to oxygen in glucose (C6H120.)?
12:12:6
01:2:1
02:1:1
6:6:12

Answers

Answer:

Either 12:12:6 or 6:6:12

Explanation:

If I remember correctly the answer should be 6:6:12

2.3 grams of sodium reacts with water and 0.080 grams of hydrogen has been collected what are the theoretical and percent yields of hydrogen gas?

Answers

Answer:

Theoretical yield = 0.1 g

Percent yield = 80%

Explanation:

Given data:

Mass of sodium = 2.3 g

Actual yield of hydrogen = 0.080 g

Theoretical yield = ?

Percent yield = ?

Solution:

Chemical equation:

2Na + 2H₂O    →  H₂ + 2NaOH

Number of moles of sodium:

Number of moles = mass/ molar mass

Number of moles = 2.3 g/ 23 g/mol

Number of moles = 0.1 mol

Now we will compare the moles of sodium with hydrogen to calculate the theoretical yield.

                       Na               :              H₂

                        2                :               1

                     0.1                 :             1/2×0.1 = 0.05 mol

Mass of hydrogen produced:

Mass = number of moles × molar mass

Mass = 0.05 mol × 2 g/mol

Mass = 0.1 g

Percent yield of hydrogen:

Percent yield = actual yield / theoretical yield ×100

Percent yield = 0.08 g/ 0.1 g×100

Percent yield = 0.8×100

Percent yield = 80%

based on the half-life of Tc-99, how many half-lives have to pass for a 150 mg sample of Tc-99 to decay down to 30mg?

Answers

Answer:

2.322 half-lives have passed to decay down from 150 miligrams to 30 miligrams.

Explanation:

The half of Technetium-99 is approximately 211000 years. The decay of isotopes is represented by the following ordinary differential equation:

[tex]\frac{dm}{dt} = -\frac{m}{\tau}[/tex] (Eq. 1)

Where:

[tex]\frac{dm}{dt}[/tex] - First derivative of isotope mass in time, measured in miligrams per year.

[tex]m[/tex] - Mass of the isotope, measured in miligrams.

[tex]\tau[/tex] - Time constant, measured in years.

Now we proceed to obtain the solution of this differential equation:

[tex]\frac{dm}{m} = -\frac{dt}{\tau}[/tex]

[tex]\int {\frac{dm}{m} } = -\frac{1}{\tau}\int dt[/tex]

[tex]\ln m = -\frac{t}{\tau}+C[/tex]

[tex]m(t) = m_{o}\cdot e^{-\frac{t}{\tau} }[/tex] (Eq. 2)

Where:

[tex]m_{o}[/tex] - Initial mass of the isotope, measured in miligrams.

[tex]t[/tex] - Time, measured in years.

The time passed for isotope is cleared within the equation described above:

[tex]\ln \frac{m}{m_{o}} = -\frac{t}{\tau}[/tex]

[tex]t = -\tau \cdot \ln \frac{m}{m_{o}}[/tex]

In addition, we can obtain the time constant as a function of half-life:

[tex]\tau = \frac{t_{1/2}}{\ln 2}[/tex] (Eq. 3)

If we know that [tex]t_{1/2} = 211000\,yr[/tex], [tex]m_{o} = 150\,mg[/tex] and [tex]m = 30\,mg[/tex], then the time passed is:

[tex]\tau = \frac{211000\,yr}{\ln 2}[/tex]

[tex]\tau \approx 304408.654\,yr[/tex]

[tex]t = -(304408.654\,yr)\cdot \ln \left(\frac{30\,mg}{150\,mg} \right)[/tex]

[tex]t \approx 489926.829\,yr[/tex]

The amount of passed half-lives is that time divided by a half-life. That is:

[tex]n = \frac{489926.829\,yr}{211000\,yr}[/tex]

[tex]n = 2.322[/tex]

2.322 half-lives have passed to decay down from 150 miligrams to 30 miligrams.

the kinetic molecules theory helps explain relastionships between ​

Answers

Answer:

hi :D

Explanation:

State the relationship between temperature and kinetic energy. The Kinetic Molecular Theory allows us to explain the existence of the three phases of matter: solid, liquid, and gas. In addition, it helps explain the physical characteristics of each phase and how phases change from one to another.

hope this helps

._.

...

The diagram illustrates photosynthesis. Which best describes what is happening in the area marked X?

Answers

Answer:

You forgot to include the diagram use snipping tool to take a picture and upload it

Explanation:

A chemist is asked to determine the specific heat capacity of an unknown mineral. The 149-g sample was heated to 92.7°C and placed into a calorimeter containing 81.4 g of water at 20.0°C. The heat capacity of the calorimeter was 12.8 J/K. The final temperature in the calorimeter was 23.7°C. What is the specific heat capacity (in J/g°C) of the mineral? Enter to 4 decimal places.​

Answers

Answer:

The specific heat of the mineral is 0.1272J/g°C

Explanation:

The sample is given energy to the calorimeter and the sample of water.

The energy released for the sample is equal to the energy absorbed for both the calorimeter and the water:

C(Sample)*m*ΔT = C(Calorimeter)*ΔT + C(water)*m*ΔT

Where C is specific heat

m is mass of the sample and water

And ΔT is change in temperature

C(Sample)*149g*(92.7°C-23.7°C) = 12.8J/K*(23.7°C-20.0°C) + 4.184J/g°C*81.4g*(23.7°C-20.0°C)

C(Sample)*10281g°C = 47.36J + 1260.1J

C(Sample) = 0.1272J/g°C

The specific heat of the mineral is 0.1272J/g°C

The specific heat of the mineral is 0.1272J/g°C

Calculation of the specific heat:

The energy released for the sample should be equivalent to the energy absorbed for both the calorimeter and the water:

So,

C(Sample)*m*ΔT = C(Calorimeter)*ΔT + C(water)*m*ΔT

here C is specific heat

m is mass of the sample and water

And ΔT is change in temperature

Now

C(Sample)*149g*(92.7°C-23.7°C) = 12.8J/K*(23.7°C-20.0°C) + 4.184J/g°C*81.4g*(23.7°C-20.0°C)

C(Sample)*10281g°C = 47.36J + 1260.1J

C(Sample) = 0.1272J/g°C

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How many protons and electrons does a hydrogen atom have?

Answers

A hydrogen atom contains 1 electron, 1 proton

Explanation:

Watts are a measurement of power

Answers

Answer:

Watts are a measurement of power, describing the rate at which electricity is being used at a specific moment. For example, a 15-watt LED light bulb draws 15 watts of electricity at any moment when turned on. Watt-hours are a measurement of energy, describing the total amount of electricity used over time.

Please mark as brainliest.

Answer: True

Watts are a measurement of power, used in light bulbs and other electricity. It is also measured as candela (C) in SI Units. The answer to the question is true because of this measurement.

Hope this helps!

If heat is required for a chemical reaction to occur, from where does the energy come?

Answers

Answer:

Chemical energy is energy stored in the bonds of chemical compounds, like atoms and molecules. This energy is released when a chemical reaction takes place. Usually, once chemical energy has been released from a substance, that substance is transformed into a completely new substance.

Explanation:

WILL MARK BRAINLIEST please

Answers

Answer:

C is the only reasonable answer.. but this is 6th grade science and I'm in 7th, so I'm pretty sure I'm right

Why is H2S called an analytical agent?​

Answers

Answer:

Hydrogen sulfide is an newly recognized signical molecule with very potent cytoprotective actions.

Consider the following statements about first ionization energies:

I. Because the effective nuclear charge for Mg is greater than that for Be, the first ionization energy of Mg is greater than that of Be.
II. The first ionization energy of O is less than that of N because in O we must pair electrons in the 2p orbitals.
III. The first ionization energy of Ar is less than that of Ne because a 3p electron in Ar is farther from the nucleus than a 2p electron in Ne.

Which of the statements I, II, and III is or are true?

Answers

Answer:

I,II, III

Explanation:

Firstly, the magnitude of nuclear charge affects the first ionization energy of an element. Hence,as effective nuclear charge increases, the attraction between the nucleus and the outermost electron increases and ionization energy consequently increases. Thus Mg has a higher first ionization energy than Be.

Secondly, oxygen has an electron configuration of 1s2 2s2 2p4 while nitrogen has an electron configuration of 1s2 2s2 2p3. Now, recall that extra energy is often associated with half filled orbitals hence nitrogen has a higher first ionization energy than oxygen. Furthermore, the addition of electron to an already half filled 2p orbital in oxygen (pairing) leads to inter electronic repulsion and drastic fall in first ionization energy. Therefore, as we move from nitrogen to oxygen in the periodic table, greater inter-electron repulsion between two electrons in the same p-orbital counter balances the increase in effective nuclear charge hence nitrogen has a greater first ionization energy than oxygen.

Lastly, the 3p orbital is far away from the nucleus hence we expect it to feel less of nuclear attraction than a 2p orbital. Hence the first ionization energy of Ar is less than that of Ne.

Why does a small pebble sink in water?

Answers

a small pebble may sink in water because it’s mass might not be that great but is the weight that matter and of it weights more than 1.0g/cm^3 (density of water)

A small pebble sinks in water because its density is greater than the density of water. Density is a measure of how much mass is packed into a given volume. If an object is denser than the liquid it is placed in, it will sink.

When a pebble is dropped into water, the water exerts an upward force called buoyancy. This force opposes the weight of the pebble, and if the pebble is less dense than water, it will experience an upward force greater than its weight and float.

However, if the pebble's density is greater than that of water, the downward force due to its weight will be greater than the upward buoyant force, causing it to sink.

Learn more about Density, here:

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how are compounds with metallic bonds similar to ionic compounds?

Answers

Answer:

Metals do not form double and triple bonds in general because metals want to lose electrons, not share, in order to become stable, and both compounds have high melting ppints

Compounds with metallic bonds and ionic compounds are similar in their melting point and boiling point, conductivity, solubility in polar solvents etc.

Ionic compounds are chemical compounds that are formed by the electrostatic attraction between oppositely charged ions.

Compounds with metallic bonds and ionic compounds are similar in several ways. Some of the similarities are:

1. High melting and boiling points: Both metallic and ionic compounds have high melting and boiling points due to the strong forces that hold the atoms or ions together.

2. Conductivity: Both metallic and ionic compounds are good conductors of electricity due to the presence of charged particles that can move freely.

3. Brittle: Ionic and metallic compounds are generally brittle in nature, meaning that they are prone to breaking or shattering when subjected to stress.

4. Solubility in polar solvents: Both metallic and ionic compounds are generally soluble in polar solvents such as water, due to the polar nature of the molecules.

In conclusion, compounds with metallic bonds and ionic compounds share several similarities. Both have high melting and boiling points, are good conductors of electricity, are brittle, and are generally soluble in polar solvents.

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A flashbulb of volume 1.70 mL contains O2(g) at a pressure of 2.30 atm and a temperature of 18.0°C. How many grams of O2(g)
the flashbulb contain

Answers

Answer:

0.0001637 mol

Explanation:

PV = nRT

Very important formula in chem

2.3 atm * 0.0017 L = n * 0.082057 * 291 K

= 0.0001637 mol O2

This concept is very important in chem, practice it.

Consider the reaction when aqueous solutions of calcium nitrate and potassium carbonate are combined. The net ionic equation for this reaction is:

Answers

Answer:

Ca2+(aq)   +  2OH-(aq)  →  Ca(OH) 2 ( s )

Explanation:

The balanced equation is given as;

Ca(NO 3 ) 2 ( aq )  +  2KOH(aq)  →  Ca(OH) 2 ( s )  +  2KNO 3 ( aq )

The net ionic equation features only ions that actually participated in the reaction. These ions are identified due to their change in oxidation numbers. Also, the aqueous compounds are broken down into ions.

Ca2+  + 2NO3-  +  2K+  +  2OH-  →  Ca(OH) 2 ( s ) +  2K+   +  2NO3-

Ions present in both sides of the equation above. These are; NO3-,  K+ and OH-

The net ionic equation is;

Ca2+(aq)   +  2OH-(aq)  →  Ca(OH) 2 ( s )

Which statements about exothermic and endothermic reactions are correct? (its a multiple choice question)

1 During an exothermic reaction, heat is given out.

2 The temperature of an endothermic reaction goes up because heat is taken in.

3 Burning methane in the air is an exothermic reaction.

A) 1.2 and 3
B) 1 and 2 only
C) 1 and 3 only
D) 2 and 3 only​

Answers

Answer:

C)1 and 3 only☺️

Explanation:

How is the periodic table generally arranged?

Answers

Answer:

It is generally arranged by the atomic number

Explanation:

Give an example of experimental bias

Answers

Answer:

chongus because he's the only good one

Which element requires the least amount of energy to remove the most loosely held electron from a gaseous atom in the ground state? 1. K 2. Kr 3. As 4.br

Answers

Answer:

K

Explanation:

A ___ reaction takes two or more reactants to make one product

Answers

Answer:

Synthesis

Explanation:

A sysnthesis reaction takes two or more reactants to create one product

Lead(II) nitrate and ammonium iodide react to form lead(II) iodide and ammonium nitrate according to the reaction

Answers

Answer:

1.186L or 1186mL.

Explanation:

The volume of a 0.290 m NH4I solution that is required to react with 253 ml of a 0.680 m Pb(NO3)2 solution is 1.186 liters or 1186 ml.

the gram formula mass of NH4Br is what (please provide explanation, thank you)​

Answers

Answer:

97.95 g/mol

Explanation:

Step 1: Define molar masses

Molar Mass of N - 14.01 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of Br - 79.90 g/mol

Step 2: Find amounts of molar masses

1 mol N - 14.01 g/mol

4 mol H - 4.04 g/mol

1 mol Br - 79.90 g/mol

Step 3: Find molar mass of compound

Molar Mass N + 4 Molar Mass H + 1 Molar Mass Br

14.01 g/mol + 4.04 g/mol + 79.90 g/mol

97.95 g/mol

Which one of these is not a characteristic of electromagnetic waves.

amplitude

wavelength

frequency

intensity

Answers

Answer:

Amplitude

Explanation:

How many protons does Lithium have?

Answers

Answer:

3 ................................

Answer: 3

Explanation:

yes

Mass of a proton =...........

Answers

Answer:

Explanation:

A proton has a mass of approximately 938 MeV/c2, of which the rest mass of its three valence quarks contributes only about 9.4 MeV/c2; much of the remainder can be attributed to the gluons' QCBE.

What change would you expect on the rate of the SN2 reaction of 1-iodo-2-methylbutane with cyanide ion if the nucleophile concentration is halved and the alkyl halide concentration is doubled

Answers

Answer:

The rate of reaction remains the same, no change is observed

Explanation:

Remember that for an SN2 reaction, the rate of reaction depends both on the concentration of the alkyl halide and the concentration of the nucleophile.

Hence we can write; Rate = k [Alkyl halide][NaI]

This implies that if we half the concentration of the nucleophile and double the concentration of the alkyl halide, the rate of reaction just remains the same since the reaction is bimolecular and first order in both alkyl halide and nucleophile

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