The periodic table of elements is organized by the number of

Answer:

5 significant figures all figures are significant except for 0

Answer:

The velocity of the ejected electron from the ionized atom is 3.6 × 10⁵ m/s

Explanation:

Using the conservation of energy, we can write that

Photon energy (E) = Ionisation energy (I.E) + Kinetic energy (K.E)

Photon  energy, E = [tex]hf[/tex]

Where [tex]h[/tex] is Planck's constant ( [tex]h[/tex] = 6.626 × 10⁻³⁴ kgm²/s)

and [tex]f[/tex] is the frequency

Also,

Kinetic energy, K.E = [tex]\frac{1}{2} mv^{2}[/tex]

Where [tex]m[/tex] is mass

and [tex]v[/tex] is velocity

Hence, we can write that

[tex]hf = I.E + \frac{1}{2}mv^{2}[/tex]

But, [tex]c = f\lambda[/tex]

where [tex]c[/tex] is the speed of light ( [tex]c[/tex] = 3.0 × 10⁸ m/s)

and λ is the wavelength

∴ [tex]f = \frac{c}{\lambda}[/tex]

Then,

[tex]\frac{hc}{\lambda} = I.E + \frac{1}{2}mv^{2}[/tex]

From the question, the first ionisation energy of sodium is 496 kJ/mol

This is the ionisation energy for 1 mole of sodium,

For 1 atom of sodium, we will divide by Avogadro's constant

∴ The ionisation energy becomes

(496 KJ/mol) / (6.02 × 10²³ molecules)

= 8.239 × 10⁻¹⁹ J

This is the ionisation energy for one atom of sodium

Now, to determine the velocity of the ejected electron from the ionized atom,

From,

[tex]\frac{hc}{\lambda} = I.E + \frac{1}{2}mv^{2}[/tex]

Then,

[tex]\frac{6.626\times 10^{-34} \times 3.0 \times 10^{8} }{225 \times 10^{-9} } = 8.239 \times 10^{-19} + \frac{1}{2}(9.109\times10^{-31} )v^{2}[/tex]

[tex]8.835 \times 10^{-19} = 8.239 \times 10^{-19} + 4.5545 \times 10^{-31}v^{2}[/tex][tex]8.835 \times 10^{-19} - 8.239 \times 10^{-19} = 4.5545 \times 10^{-31}v^{2}[/tex]

[tex]5.96 \times 10^{-20} = 4.5545 \times 10^{-31}v^{2}[/tex]

[tex]v^{2} = \frac{5.96 \times 10^{-20}}{4.5545 \times 10^{-31}}[/tex]

[tex]v^{2} = 1.3086 \times 10^{11}[/tex]

[tex]v = \sqrt{1.3086 \times 10^{11} }[/tex]

[tex]v = 361745.77 m/s[/tex]

[tex]v = 3.6 \times 10^{5} m/s[/tex]

Hence, the velocity of the ejected electron from the ionized atom is 3.6 × 10⁵ m/s

Answer:

The volume (mL) of 0.135 M NaOH that is required to neutralize 13.7 mL of 0.129 M HCl is 13.1 mL (option b).

Explanation:

The reaction between an acid and a base is called neutralization, forming a salt and water.

Salt is an ionic compound made up of an anion (positively charged ion) from the base and a cation (negatively charged ion) from the acid.

When an acid is neutralized, the amount of base added must equal the amount of acid initially present. This base quantity is said to be the equivalent quantity. In other words, at the equivalence point the stoichiometry of the reaction is exactly fulfilled (there are no limiting or excess reagents), therefore the numbers of moles of both will be in stoichiometric relationship. So:

V acid *M acid = V base *M base

where V represents the volume of solution and M the molar concentration of said solution.

In this case:

Replacing:

0.0137 L* 0.129 M= V base* 0.135 M

Solving:

[tex]V base=\frac{0.0137 L*0.129 M}{0.135 M}[/tex]

V base=0.0131 L = 13.1 mL

The volume (mL) of 0.135 M NaOH that is required to neutralize 13.7 mL of 0.129 M HCl is 13.1 mL (option b).

Answer:

SO42 - Trigonal planar ion

Explanation:

The SO4^2- ion is tetrahedral and not trigonal planar because the sulphur atom has four regions of electron density which includes the lone pair of electrons on sulphur atom.

This accounts for the observed tetrahedral arrangement of electron pairs around the central sulphur atom in SO4^2- ion, hence the answer.

Answer:

Mass of copper is 500.542 g.

Explanation:

Initial temperature of copper = [tex]122^{0}[/tex]C

specific heat capacity of copper = 0.20 J/°C g

Mass of water = 500 g

Initial temperature of water = [tex]25.3^{0}[/tex]C

Specific heat capacity of water = 4.2 J/°C g

Final temperature of water and copper = [tex]29.7^{0}[/tex] C

Heat loss by copper = Heat gained by water

[tex]m_{c}[/tex][tex]c_{c}[/tex]Δ[tex]T_{c}[/tex] = [tex]m_{w}[/tex][tex]c_{w}[/tex]Δ[tex]T_{w}[/tex]

[tex]m_{c}[/tex] x 0.2 x (122 - 29.7) = 500 x 4.2 x (29.7 - 25.3)

[tex]m_{c}[/tex] x 0.2 x 92.3 = 500 x 4.2 x 4.4

[tex]m_{c}[/tex] x 18.46 = 9240

[tex]m_{c}[/tex] = [tex]\frac{9240}{18.46}[/tex]

     = 500.5417

mass of copper is 500.542 g.

Answer:

500.542

Explanation:

edge

Answer:

Molar concentration of the Fe³⁺ in the unknown solution is 8.01x10⁻⁵M.

Explanation:

When you make a calibration curve in a spectrophotographic analysis you are applying the Lambert-Beer law that states the concentration of a compound is directely proportional to its absorbance:

A = E*l*C

Where A is absorbance, E is molar absorption coefficient, l is optical path length and C is molar concentration

Using the equation of the line you obtain:

y = 4541.6X + 0.0461

Where Y is absorbance and X is concentration -We will assume concentration is given in molarity-

As absorbance of the unknown is 0.410:

0.410 = 4541.6X + 0.0461

X = 8.01x10⁻⁵M

Answer:

1. Democritus- Matter was made of

different kinds of things.

2. Bernoulli- Gases are formed from tiny particles so small you can't see them. The particles are spread out into a certain area and move when people walk through them.

3. Priestley- Substances combine or

break apart to create new different substances.

Explanation:

1. Democritus was a Greek philosopher regarded to be the "Father of Science". He discovered that all matter were composed of indestructible things he called ATOMOS. Hence, his idea was that Matter was made of different kinds of things (atoms).

2. David Bernoulli, a mathematician, was born in 1700. He contributed immensely to the kinetic molecular theory of gases. In his postulated theory, he gave the idea that gases are formed from tiny particles so small you can't see them. The particles are spread out into a certain area and move when people walk through them.

3. Priestley- Joseph Priestley, born in 1733, is widely known for his discovery of oxygen gas among other gases. His idea was that substances combine or

break apart to create new different substances.

Answer:

Take approx 41.7 mL of 12-M HCl in a 1.00-L flask and fill the rest of the volume with distilled water.

Explanation:

Hello,

In this case, for the dilution process from concentrated  12-M hydrochloric acid to 1.00 L of the diluted 0.50M hydrochloric acid, the volume of concentrated HCl you must take is computed by considering that the moles remain constant for all dilution processes as shown below:

[tex]n_1=n_2[/tex]

Which can also be written in terms of concentrations and volumes:

[tex]M_1V_1=M_2V_2[/tex]

Thus, solving for the initial volume or aliquot that must be taken from the 12-M HCl, we obtain:

[tex]V_1=\frac{M_2V_2}{M_1} \\\\V_1=\frac{1.00L*0.5M}{12M}\\ \\V_1=0.0417L=41.7mL[/tex]

It means that you must take approx 41.7 mL of 12-M HCl in a 1.00-L flask and fill the rest of the volume with distilled water for such preparation.

Best regards.

Answer:

10

Explanation:

no explanation need thats the right answer i gotchu g

Answer:10

Explanation:

no explanation need thats the right answer

Answer:

Earth's gravitational pull

Explanation:

Astronauts in the space shuttle float because they are in “free fall” around Earth, just like a satellite or the Moon. Again, it is gravity that provides the centripetal force that keeps them in circular motion.

Answer:

15. Velocity = 3 X 10^8

     Distance = 1580 m

time = distance / velocity

t = 1580 / 3 * 10^8

t =  1580 * 10^-8 / 3

t = 158 * 10^-7/3

t = 5.26 * 10^-8 seconds  

16. Converting the distance to 'm'

Given distance (in miles), multiplying by 1.609 to convert to  km and also multiplying by 1000 to convert to 'm'

s= 4.8 * 1.609 * 10^7 * 1000

v = 3 * 10^8

t =  4.8 * 1609  * 10^7 / 3 * 10^8

t = 1.6 * 1609 * 10^-1

t = 2574.4 * 10^ -1

t = 2.5744 * 10^-4 s

17. Mass in 1 tsp of medicine = 5 mL at a density of 25 mg/mL

Mass in 1 tsp of medicine = 5 * 25 = 125 mg

Mass prescribed by the doctor  = 375 mg

Number of table spoons required = Mass prescribed / Mass in 1 tsp

N = 375/125 = 3 table spoons of the medicine

18. Density of medicine = 400g/ 5mL = 80g / mL

Medicine required = 1500 g

Volume of medicine required = Medicine Required / Density of medicine

Volume = 1500 / 80 = 18.75 mL of medicine is required

Hence, the volume of the suspension should be at least 18.75 mL

19. Volume of 10 drops = 1 mL

Volume of 5 drops = 1/2 mL

The faucet is leaking 5 drops or 1/2 mL water per minute

Number of minutes in a day = 60 * 24  = 1440 minutes in a day

Water leaked in 1440 minutes = 1440 * 1/2 = 720

0.720 L (720 mL) Water leaked from the faucet in a day

Kindly mark Brainliest, Thanks

Answer:

2 AgNO₃(aq) + NiCl₂(aq) ⇒ 2 AgCl(s) + Ni(NO₃)₂(aq)

Explanation:

Let's consider the double displacement reaction in which aqueous silver nitrate reacts with aqueous nickel(II) chloride to produce solid silver chloride and aqueous nickel(II) nitrate.

AgNO₃(aq) + NiCl₂(aq) ⇒ AgCl(s) + Ni(NO₃)₂(aq)

We have 2 atoms of Cl on the left side, so we will add a stoichiometric coefficient 2 to AgCl.

AgNO₃(aq) + NiCl₂(aq) ⇒ 2 AgCl(s) + Ni(NO₃)₂(aq)

Now, we have 2 atoms of Ag on the right side, so we will add a stoichiometric coefficient 2 to AgNO₃.

2 AgNO₃(aq) + NiCl₂(aq) ⇒ 2 AgCl(s) + Ni(NO₃)₂(aq)

Now, the equation is balanced.

The balanced chemical equation for the reaction is

2AgNO₃(aq) + NiCl₂(aq) → 2AgCl(s) + Ni(NO₃)₂(aq)

To write a balanced chemical equation for the reaction between aqueous silver nitrate and aqueous nickel(II) chloride to produce solid silver chloride and aqueous nickel(II) nitrate

First, we will write the chemical formula for the each of the reactants and products

That is,

Silver nitrate - AgNO₃

Nickel(II) chloride - NiCl₂

Silver chloride - AgCl

Nickel(II) nitrate - Ni(NO₃)₂

Now, for the balanced chemical equation for the reaction

The balanced chemical equation for the reaction is

2AgNO₃(aq) + NiCl₂(aq) → 2AgCl(s) + Ni(NO₃)₂(aq)

Hence, the balanced chemical equation for the reaction is 2AgNO₃(aq) + NiCl₂(aq) → 2AgCl(s) + Ni(NO₃)₂(aq)

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Answer:

Slower

Explanation:

Different forces, such as gravity, can affect an object in many ways.

Scenario 1: A car is climbing a hill and then starts to coast.

Here, when the car starts to not accelerate anymore, gravity could pull it to slow down and eventually stop.

Scenario 2: A car is speeding downwards.

Here, when the car isn't on the gas pedal, gravity could act upon the car and make it go faster.

forces can make things move faster or slower them down.

Answer:

Explanation:

For the pH value of a buffer solution , the Henderson formula given is as follows

pH = pKa + log [ A⁻] / [AH ]

Now let us discuss about the phosphoric and succinic acid . The phosphoric acid has a pKa value of 2.3 and for succinic acid , the pKa value is 4.2 . The pKa value of succinic acid is more close to 5 . So to achieve pH value of 5 , succinic acid is a better alternative . The value of  [ A⁻] / [AH ]  is kept almost equal to 1 to increase the buffer capacity .

Answer:

Explanation:

B

Answer:

A. np and nf

Explanation:

The electron distribution into energy levels or sublevels of atoms can be shown in their sublevel notations. This shows the sequence of filling electrons into the orbitals of the sublevels as guided by some principles such as the Aufbau Principle, Pauli Exclusion Principle, Hund's Rule of Maximum Multiplicity e.t.c

The maximum number of electrons in the orbitals of sublevels are two for s-sublevel(one orbital), six for p-level (three orbitals), ten for d-sublevel (five orbitals), and fourteen for f-sublevel (seven orbitals). This explains that the maximum number of electrons in an orbital is two.

Answer:

They can only be broken down to the Atom like neutron proton and electrons. I hope that help

The best option which describes the burning of a house from a thermo

dynamical standpoint is ∆H > 0, ∆S > 0

Increase in temperature in a system will cause an increase in the heat

energy and a corresponding increase in the entropy of a system and are

denoted by ∆H and ∆S respectively.

∆H  and ∆S  being greater than zero signifies an increase in both

conditions. Heat energy and the degree of randomness will be increased

when the house is burning which makes ∆H > 0, ∆S > 0 correct.

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Answer:

protons and neutrons are found in nucleus

Answer:

Mass by mass

Explanation:

Because it's telling only about mass in grams

Answer:

A. Density of object = 0.86 g/mL

B. The object will float in the water.

Explanation:

The following data were obtained from the question:

Volume of water = 6.2 mL

Mass (m) of object = 1.2 g

Volume of water + Object = 7.59 mL

Density of object =?

Density of water = 1 g/mL

Next, we shall determine the volume of the object. This can be obtained as follow:

Volume of water = 6.2 mL

Volume of water + Object = 7.59 mL

Volume of object =?

Volume of object = (Volume of water + Object) – (Volume of water)

Volume of object = 7.59 – 6.2

Volume of object = 1.39 mL

Therefore, the volume of the object is 1.39 mL

A. Determination of the density of the object.

Mass (m) of object = 1.2 g

Volume (V) of object = 1.39 mL

Density (D) of object =?

Density = mass /volume

Density = 1.2/1.39

Density of object = 0.86 g/mL

B. Determination of whether the object will float or sink.

Density of object = 0.86 g/mL

Density of water = 1 g/mL

From the above, we can see that the density of water is greater than that of the object. This implies that the object is lighter than water. Therefore, the object will float in the water.

Answer:

A.

Explanation:

It’s just right

Answer:

[tex]15molH[/tex]

Explanation:

Hello,

In this case, given that one mole of glucose, contains six moles of oxygen (subscript), we can also see it contains twelve moles of hydrogen (subscript), therefore, the moles of hydrogen in the sample are computed by:

[tex]0.75molO*\frac{1molC_6H_{12}O_6}{6molO}*\frac{12molH}{1molC_6H_{12}O_6}\\ \\=1.5molH[/tex]

Best regards.

Answer:

312.5J

Explanation:

K.E=1/2*mv°2

=1/2*25*25

=312.5

Answer: My data strongly supported my hypothesis. I was right when guessed the solids density would be higher than the liquids and also that the mass affected the volume of the objects. The experiment proves that hypothesis is correct. To test further I could use different types of liquid and rocks with material.

When I predicted that solids would have a higher density than liquids and that mass would affect the volume of the objects.

I may use different sorts of fluids and rocks with stuff to test further.

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Answer:

1. Democritus - Matter was made of different kinds of things.

2. Bernoulli- Gases are formed from tiny particles so small you can’t see them. The particles are spread out into a certain area and move when people walk through them.

3. Priestley- Substances combine or break apart to create new, different substances.

Explanation:

1. Democritus was a philosopher who because of his immense contribution to atomic theory was regarded as the "FATHER OF SCIENCE". His idea was that matter was made of different kinds of things called which he called ATOMOS meaning ATOM.

2. Daniel Bernoulli was another outstanding mathematician and scientist who played a major part in the kinetic molecular theory of gases via his "HYDRODYNAMICA". His idea, which states that "gases are formed from tiny particles so small you can’t see them. The particles are spread out into a certain area and move when people walk through them"

was based on fluid dynamics.

3. Joseph Priestley is remarkably known for his 1774 discovery of oxygen. His findings that air is a mixture of gases and not just a substance made of one element paved the way for his idea that " Substances combine or break apart to create new, different substances".

Answer:

The creation of regulations that limit timber activities and the exploitation of wood can prevent soil erosion in Troy.

Explanation:

The exploitation of the wood was an intense activity and that did not have any regulation that would limit its damages, caused by its exploratory activities.

As the timber market was totally undisciplined, the exploitation of the wood caused a strong deforestation, leaving the soil totally unprotected and susceptible to strong erosion.

Soil erosion has a very negative impact on the environment, requiring regulations to be made to prevent this from happening.

Based on this, we can say that one way to prevent environmental problems in the seaport of troy is by establishing laws and regulations that limit logging activities.