How would the structure of an atom that has an atomic number of 9 and a mass number of 19
differ from the structure of an atom that has an atomic number of 8 and a mass number of 16?

Answer:

(1.45/237) x 6.02x10^23=  0.0368x10^23=3.68x10^21

Explanation:

Final answer:

To find the number of representative particles in 1.45g of a compound with a molar mass of 237g, calculate the moles and multiply by Avogadro's number, resulting in approximately 3.6859 x 10²¹particles.

Explanation:

To calculate the number of representative particles in 1.45g of a molecular compound with a molar mass of 237g, we will first determine the number of moles of the compound using the given mass and then multiply it by Avogadro's number.

Calculate moles: Number of moles = mass (g) / molar mass (g/mol) = 1.45g / 237g/mol.

Multiply by Avogadro's number to find the number of particles: Number of particles = Number of moles x Avogadro's number (6.02 x10²³ particles/mol).

Number of moles = 1.45g / 237g/mol = 0.0061224 mol.

Number of particles = 0.0061224 mol x6.02 x 10²³ particles/mol = 3.6859 x10²¹ particles.

The substances in a heterogeneous mixture can usually be seen and are easily separated, exemplified by a mixture of sand and water. Option B is correct.

The substances in a heterogeneous mixture can usually be seen and are easily separated. A heterogeneous mixture consists of two or more substances that are not uniformly distributed, meaning the different components can usually be observed with the uncovered eye.

An example of a heterogeneous mixture is a mixture of sand and water, where the sand can be easily seen and separated from the water by simple means such as filtration.

In contrast, a homogeneous mixture is uniform, meaning its composition is the same throughout, and the different components cannot be seen. Salt dissolved in water is an example of a homogeneous mixture because the salt is evenly distributed within the water and cannot be seen separately.

Hence, B. is the correct option.

Answer:

250 mg

Explanation:

1 g = 1000 mg

0.25 x 1000 = 250

0.25 grams is equivalent to 250 milligrams. This conversion is done by multiplying the amount in grams by 1000, which is the conversion factor for grams to milligrams.

The student is asking how to convert grams (g) to other units of mass. In this case, 0.25 grams is equivalent to 250 milligrams (mg). One gram is equivalent to 1000 milligrams, so we can convert the 0.25 grams into milligrams by multiplying by 1000.

To carry out the calculation :

Thus, 0.25 grams (g) is equivalent to 250 milligrams (mg), and so the correct answer is 250 mg. The options stating 0.025 kg and 0.025 mg are incorrect since they portray conversion factors inaccurately. The same applies for the 250 kg option, it is far beyond the original value.

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Answer:

Explanation:

The normal boiling point of water is 100°C. That is the temperature at which water boils when the atmospheric pressure is 1 atm, i.e. at sea level.

The liquids boil when its vapor pressure equals the atmospheric pressure; so the higher the atmospheric pressure the higher the boiling point, and the lower the atmospheric pressure the lower the boiling point.

Since, it is stated that the altitude of Denver, Colorado is 1,600 m, the atmosperic pressure (ther pressure exerted by the columnn of air above the place) is lower than 1 atm (atmospheric pressure at sea level).

Hence, water boiling point in Denver is lower than 100°C.

The graphs shown represent the temperature (T °C) as water is heated. Since when liquids boil their temperature remains constant during all the phase change, the flat portion of the graph represents the time during which the substance is boiling.

In the graph A, the flat portion is below 100°C; in the graph B, the flat portion is at 100 °C; in the graph C the flat part is above 100ªC, and, in graph D, there is not flat part. Then, the only graph that can illustrate water boiling in Denver, Colorado is the graph A.

Answer:

Metals are good conductors of electricity because the valence electrons in metallic crystals are free to move.

Explanation:

Metallic bonds joins atoms of metals and alloys together. The formation of this bond type is favoured by large atomic radius, low ionization energy and a large number of electrons in the valence shell.

The metallic bond is responsible for the bulk of the physical properties of metals we know such as malleablility, ductility, electrical and thermal conductivity e.t.c.

Answer:

True it can be misinterpreted.

Explanation:

Answer:

Chemical properties would be like what you would make food with because you are changing the structure of the ingredients.

Physical properties would be like a chair or the device you asked this question on.

Explanation:

Objects in your home, such as an iron skillet or a plastic water bottle, have both chemical and physical properties. The skillet can rust, which is a chemical property, and is also hard, a physical property. The water bottle is made of polymers (a chemical property) and is also transparent and flexible (physical properties).

Many objects in your home have both chemical and physical properties. For example, an iron skillet has the chemical property of being able to rust when exposed to water and air, a physical property of this skillet is its hardness or rigidity. Similarly, a plastic water bottle has the chemical property of being made up of polymers, which are long chains of repeating molecules, and a physical property would be its transparency or flexibility.

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Answer:

C6H1206 + 6O2  > 6CO2  + 6 H2O

Explanation:

On the left side we have  6xC so we multiply CO2 by 6 to get the same amount of C.

We have 12x H on the left side, so we multiply H2O on the right side by 6 to get the same amount of H.

On the right side we have 18x O ( 6CO2 gives us 6x2x O which is 12O; and 6H2O gives us 6O.  To get the same amount on the left side ( we already have 6O in C6H12O6), so we only need 12 O more. So we multiply O2 on the left side by 6. Which gives us 18x O on both sides.

So on both sides we have now:

6x C

12xH

18xO

Answer:

Scientific inquiry

Explanation:

A scientific inquiry is a systematic way of finding out about certain phenomena in our environment through the use of careful observations and experimentation. It follows a series of steps and procedures which helps a scientist to critically think and observe certain events in his environment. Through the observations, scientific conclusions are then drawn.

Answer:

The energy emitted by sodium atoms is 33.38 j.

Explanation:

Given data:

Wavelength of photon = 589 nm   or  5.89 × 10⁻⁷m

Mass of excited sodium atoms = 3.78 mg

Energy emitted by 3.78 mg sodium atoms = ?

Solution:

First of all we we will calculate the energy of photon at given wavelength.

E = h.c/ λ

h = planck's constant =  6.626 × 10⁻³⁴  J.s

c = 3 × 10⁸ m/s

E = ( 6.626 × 10⁻³⁴  J.s × 3 × 10⁸ m/s ) / 5.89 × 10⁻⁷m

E = 19.878 × 10⁻²⁶  J.m / 5.89 × 10⁻⁷m

E =  3.375 × 10⁻¹⁹ J

Now we will calculate the number of atoms in 3.78 mg of sodium.

Mass of excited sodium = 0.00378 g  or 3.78 × 10⁻³ g

Molar mass of sodium = 23 g/mol

We know that   23 g of sodium = one mole = 6.02 × 10²³ atoms

(3.78 × 10⁻³ g / 23 g ) × 6.02 × 10²³ atoms = 0.989 × 10²⁰ atoms

The number of atoms are 0.989 × 10²⁰ atoms.

E =   0.989 × 10²⁰ × 3.375 × 10⁻¹⁹ J = 33.38 j

To calculate the energy emitted by 3.78 mg of sodium atoms, one must find the number of photons and the energy per photon, given the wavelength of 589 nm. The steps involve calculating the number of moles, multiplying by Avogadro's number, and using the energy formula for a photon (E = hc/λ).

The question asks how much energy is emitted by 3.78 mg of excited sodium atoms emitting light at a wavelength of 589 nm. To find this out, we need to calculate the number of photons that can be emitted by the given mass and then calculate the energy of each photon.

First, we'll find out the number of moles of sodium in 3.78 mg:

Number of moles = Mass (g) / Molar mass of sodium (Na) = 3.78 x 10-3 g / 22.99 g/mol

Then, we will multiply the number of moles by Avogadro's number to get the number of sodium atoms.

Now, the energy (E) of a single photon is given by E = hc/λ, where h is Planck's constant (6.626 x 10-34 J*s), c is the speed of light (3.00 x 108 m/s), and λ is the wavelength of light. Substituting the given wavelength value of 589 x 10-9m and solving the equation provides the energy of a single photon.

Finally, by multiplying the energy of one photon by the total number of sodium atoms, we can estimate the total energy emitted.

Answer:

Explanation:

Persons body temperature

Answer: Change in air temperature is the independent variable

Explanation:

The independent variable can be defined as the factors that is under control of the experimenter.

There can be changes in the air temperature based on that the temperature of the body will change.

So, in this condition the independent variable is air temperature and dependent variable is body temperature.

Answer:

Si ⇔ Neon

Fr ⇔ Radon

Hg ⇔Xenon

V ⇔Argon

Explanation:

Silicon (Si) is, part of the carbon-group, and has atomic number 14. This means it has 14 protons and 14 elecrons ( same amount), as well as 14 protons ( 28-14).

⇒There are 14 electrons spread over 3 shells.

If we look closer to the electron configuration of a silicon atom:

₁₄Si 1s² 2s² 2p⁶ 3s² 3p²  ⇔ this is  [Ne] 3s² 3p²

⇒ Neon (Ne) is noble gas ( group 18)  with atomic number 10.

⇒The following orbital is 3s, which is complete with 2 electrons.

⇒The next orbital is 3p, and Silicon is the second element in that section, so two electrons are used.

Francium (Fr) is part of the alkali / lithium group and has atomic number 87. This means it has 87 protons and 87 electrons ( same amount), and 136 neutrons  (223 - 87).

⇒There are 87 electrons spread over 7 shells.

If we look closer to the electron configuration of a francium atom:                                                    

₈₇Fr 1s²2s²2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² 6p⁶ 7s¹ ⇔ this is [Rn] 7s¹

⇒ radon (Rn) is noble gas( group 18) with atomic number 86

⇒we will see that the  4 s  orbital fills with electrons before any of those in the  3 d  subshell as the  4 s  orbital is lower in energy than the  3 d s, and it is favorable for electrons to fill low-energy orbitals first (closer to the nucleus)

⇒Francium will fill orbitals all the way up to the  7 s  subshell, where it will have a half-filled orbital:   7 s 1

Mercury (Hg) is part of the zinc group, and has atomic number 80. This means it has 80 protons and 80 electrons ( same amount), and 121 neutrons ( 201 - 80).

⇒There are 80 electrons spread over 6 shells

If we look closer to the electron configuration of a Mercury atom:                                                            

₈₀Hg 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶ 4d¹⁰ 5s² 5p⁶ 4f¹⁴ 5d¹⁰ 6s² ⇔  this is[Xe] 4f¹⁴ 5d¹⁰ 6s²

⇒xenon (Xe) is noble gas ( group 18) with atomic number 54.

⇒After the 6s orbital is filled, 4f fills next (can hold 14 electrons) because it lower in energy than 5d.  

⇒Then, the 10 remaining electrons will go in the 5d orbital. The f orbitals will always be one principle quantum number(n) behind the d orbitals.

Vanadium (V) is part of the vanadium group, and has atomic number 23. This means it has 23 protons and 23 electrons (same amount), and 28 neutrons (51 - 23).

⇒There are 23 electrons spread over 4 shells

If we look closer to the electron configuration of a vanadium atom:                                                  

₂₃V 1s² 2s² 2p⁶ 3s² 3p⁶ 3d³ 4s² ⇔ this is [Ar] 3d³ 4s²

⇒argon (Ar) is a noble gas (group 18) with atomic number 54.

⇒ When the atom of V releases 5 electrons from 3d and 4s orbital, V ion (V5+) will attain the octet structure, 1s2 2s2 2p6 3s2 3p6 which is same as Argon

Answer:

Neon (Ne) for Silicon (Si)

Radon (Rn) for Francium (Fr)

Xenon (Xe) for Mercury (Hg)

Argon (Ar) for Vanadium (V)

Explanation:

Did it on edge

Answer:

On the periodic table, metals are separated from nonmetals by a zig-zag line stepping through carbon, phosphorus, selenium, iodine, and radon. ... Elements just to the left of the line may be termed metalloids or semimetals and have properties intermediate between those of the metals and nonmetals.

Explanation:

Final answer:

Elements are categorized on the periodic table as metals, nonmetals, and metalloids, with metals being lustrous and good conductors, nonmetals being dull and poor conductors, and metalloids exhibiting intermediate properties.

Explanation:

The periodic table organizes elements into categories based on their properties. The main categories are metals, nonmetals, and metalloids (or semimetals). Metals, which occupy the left three-fourths of the periodic table, are generally shiny and silvery, excellent conductors of electricity and heat, and are malleable and ductile. On the contrary, nonmetals are typically found in the upper right-hand corner of the periodic table and tend to be dull, poor conductors of electricity and heat, and brittle in their solid form.

Metalloids, found along the zigzag line between metals and nonmetals, have properties that are intermediate between the two. For example, metalloids are semiconductors due to their unique electrical properties, which are crucial for creating transistors and other solid-state devices.

Heat or electricity in the atmosphere

Answer:

Option (4)

Explanation:

The Plasma is formed when a gas is heated and becomes very hot. Due to this heating of gas, the atoms within the gas acquires a huge amount of energy. This energy facilitates the electrons to get eliminated from its nucleus of the gas atoms.  

In simple words, plasma is defined as the ionized gas.

These plasma forms more than 99% of the universe that is visible to us. At night, these plasma appears to shine in the form of nebula, stars and auroras that is formed in the atmosphere of both the poles.  

Thus, the plasma are formed due to heating or electricity in the atmosphere.

Hence, the correct answer is option (4).

Answer:

B. The theory might be modified if necessary.

B. nearly all scientists agree that it is correct

Explanation:

B. The theory might be modified if necessary.

The Bernoulli's principle relates the speed of fluid to their pressures. It simply states that when the speed of fluids increases there is a drop in pressure.

Supposing we find new evidence about how the principle works, the normal scientific thing to do is to modify the existing principle. New information and observations about a principle would only provide a modification to the existing one. An example is the Dalton's atomic theory, which was centered on the atom being the smallest indivisible particle: the theory was later modified when new ideas about the atom surface.

B. nearly all scientists agree that it is correct

Before a hypothesis is adopted to the context of scientific principle, the ideas behind it must have tested and must be repeatable. Different sources will verify the authenticity of such scientific claim to see if such can be adopted. Therefroe, nearly a large numbr of scientists must agree that it is correct.

Answer:

Which statements describe lattice energy?

B,C,D

Explanation:

just did it

Answer: 39 electrons

Explanation: Subtract 79 by 40 to get the atomic number (amount of protons) which is 39. The number of electrons must be the same as the number of protons if it's not an ionic compound so the amount of electrons is the same amount of protons.

To find the number of electrons in an atom, identify the atomic number which is equal to the number of protons. Since the mass number is 79 and the isotope has 40 neutrons, the number of protons is 39, meaning an atom of this isotope also has 39 electrons.

In order to find the number of electrons in an isotope of an element, we need to identify the atomic number of the isotope. The atomic number is equal to the number of protons in the nucleus of the atom, which is also equal to the number of electrons in a neutrally charged atom.

The mass number of an isotope is the total number of protons and neutrons in the nucleus. Given that the mass number is 79 and the isotope has 40 neutrons, we can subtract the number of neutrons from the mass number to find the number of protons: 79 - 40 = 39.

Therefore, we can conclude that the volumetric element has 39 electrons. This is because in a neutrally charged atom, the number of electrons equals the number of protons.

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Answer:

A diamond is a pure substance because it is made of one element.

Explanation:

From the crystalline structure model of the diamond, we can see that we only have just one element represented by the green balls connected in a cross linked fashion to one another. Therefore, one can rightly conclude that this is a pure substance made up of one element.

In a pure substance, all parts are homogeneous and composition is definite.

Answer:

Find the mass of a container.

Add 250 to the quantity and move the brokers to that value.

Add the sugar to the dough container until it reaches zero in the balance.

And ready, you will have the 250 g of sugar.

Explanation:

The triple beam balance is an instrument used to measure the mass quite accurately. This device has an approximate reading error of +/- 0.05 grams. The name refers to the three beams, the largest central beam, the front beam, medium size, and the furthest beam, smallest size. The triple beam balance can be used to measure the mass from objects, find the mass by the difference in the case of a liquid, and measure a substance.

To use a triple beam balance and get 250 grams of sugar, follow the  steps explained below

To use a triple beam balance and get 250 grams of sugar when baking, do these steps:

To start using the triple beam balance, put it on a table or desk that is sturdy and level. Make sure the balance is set up and positioned correctly.

Make sure all three beams are at zero by adjusting the riders or knobs until they line up with the zero marks.

Put a empty container on the weighing scale. If needed, change the zero marks again to include the weight of the container.

Put sugar in the container: Gently add sugar to the measuring container until the balance pointer moves slightly below the zero mark. This means that the sugar is heavier than the counterweight.

Balance the scales: Begin by focusing on the biggest beam (the one with the largest weight that can slide). Shift the heaviness along the long object towards the starting point until the arrow is flat. Do this again for the next two beams. Start with the second biggest beam, and then do the smallest beam.

Adjust the balance carefully: When the pointer is near the zero mark, use the smaller numbers on each side to change the weights until the pointer is perfectly aligned with the zero mark.

Take a look at the measurement: Combine the numbers on each side to find out the total weight of the sugar in grams. The total of the numbers on the beams equals the amount of sugar in the container.

Change the amount of sugar: If you have too much sugar (more than 250 g), take some of it out with a spatula or scoop until you have the right amount. If the weight is less than 250 g, add more sugar until you reach the desired amount.

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Answer:

B.

Will providing sunflowers with Fertilizer X cause the flowers to produce more seeds?

Explanation:

The question B is a sort of untested idea. It is the ideal hypothesis for Regina to test and see if the brand of the fertilizer will improve her sunflower seed production.

To scientifically carryout this test, Regina must set up an experiment. The experiment will help her affirm her grandfather's observation about the fertilizer.

The dependent variable here is the yield of the sunflower as we know. The sunflower will produce more seeds based on how nourished it is with available nutrients.

In her experiment, she can use the normal soil, soil with fertilizer x and maybe organic manure mixed with soil to compare different results. She then proceeds to plant her seed and on the long run observe the output.

From the result of her experiment, she can then conclude on her hypothesis. With the experiment, she can prove wether the fertilizer will improve the yield of the seeds or not.

Answer:

The answer is B - Will providing sunflowers with Fertilizer X cause the flowers to produce more seeds?

Explanation:

I had the question a little bit of go and it was B and I got it right.

Answer: 3.64 hours

Explanation:

Formula of Average speed : [tex]\text{Average speed}=\dfrac{\text{Distance}}{\text{Time}}[/tex]

Given : Distance = 200km    ; Average speed = 55 km/ hr

To find : Time

Substitute values for distance and average speed in the above formula , we get

 [tex]55=\dfrac{200}{\text{Time}}\\\\\Rightarrow\text{Time}=\dfrac{200}{55}=3.63636363636\approx3.64\ hr[/tex]

Hence, it would take 3.64 hours for a car to travel 200km .

Answer:Convection currents drive the movement of Earth's rigid tectonic plates in the planet's fluid molten mantle. In places where convection currents rise up towards the crust's surface, tectonic plates move away from each other in a process known as seafloor spreading (Fig. 7.21).

Explanation:

Convection drives plate movement because of high convection current on the Earth’s core.  It makes molten rocks to move in molten layer.

Explanation:

In the aesthenosphere, high convection currents pass heat on the surface, where less dense magma leaves break down plates in distribution centres and create different plate boundaries.

When the plate moves away from the propagation centres, they also cool down to higher-density rocks, which are part of the oceanic crust consumed in ocean subduction areas. Then, the crust returns to aesthenosphere.

Generally, the heat generated by the radioactive decomposition of elements deeper in the Earth produces magma (molten rock) in aesthenosphere. It (70 to 250 km) is a part of mantle, the central globe, extending over 2,900 km.

Answer: Would Be A

Explanation:

You would do that because in the scientific method it said make a question, hypothesize and test the idea and make conclusions.

Answer:

the answer is A).

Explanation:

Answer:

86 mL

Explanation:

First find the moles of Pb (NO3)2

n=cv

where

c ( concentration)= 0.210 M

v ( volume in L) =0.05

n= 0.210 × 0.05

n= 0.0105

Using the mole ratio, we can find the moles of KCl by multiplying by 2

n (KCl) =0.0105 ×2

=0.021

v (KCl)= n/ c

= 0.021/ 0.244

=0.08606557377

=0.086 L

= 86 mL

Answer:

The volume of 0.244 M KCl solution is required 86.07 mL.

Explanation:

[tex]Concentration=\frac{Moles}{Volume (L)}[/tex]

Moles of lead nitrate in 50.0 mL of 0.210 M solution be n.

Molarity of the lead nitrate solution = 0.210 M

Volume of the solution = 50.0 mL = 0.050 L ( 1 mL = 0.001 L)

[tex]0.210 M=\frac{n}{0.050 L}[/tex]

[tex]n=0.210 M\times 0.050 L=0.0105 mol[/tex]

According to reaction given, 1 mole of lead nitrate reacts with 2 moles of KCl.

Then 0.0105 moles of lead nitrate will react with:

[tex]\frac{2}{1}\times 0.0105 mol=0.021 mol[/tex] of KCl

Moles of KCl = 0.021 mol

Volume of KCl solution = V

Molarity of the KCl solution = 0.244 M

[tex]0.244 M=\frac{0.021 mol}{V}[/tex]

[tex]V=\frac{0.021 mol}{0.244 M}=0.08607 L = 86.07 mL[/tex]

The volume of 0.244 M KCl solution is required 86.07 mL.

The problem gives us the percentages for carbon and hydrogen in the unknown acid:

54.5 % carbon

9.10 % hydrogen

The difference until 100 % is oxygen:

36.4 % oxygen

Now we may calculate the empirical formula of the unknown acid:

First we divide each percentage by the atomic mass of each component:

carbon = 54.5 / 12 = 4.54

hydrogen = 9.1 / 1 = 9.1

oxygen = 36.4 / 16 = 2.28

Now we divide the answers to the smallest number, which is 2.28:

carbon = 4.54 / 2.28 = 2

hydrogen = 9.1 / 2.28 = 4

oxygen = 2.28 / 2.28 = 1

Now the empirical formula for the acid will be:

C₂H₄O₁

And molecular formula:

(C₂H₄O₁)ₓ , but here we do not have enough information to determine unknown "x".

Answer:

2Al + 3H2SO4 (g) → Al2(SO4)3 (aq) + 3H2 (g)

Explanation:

On the right side we have Al2 ( so 2x aluminium, So  on the left side we multiply Al by 2, On both sides is 2x Al now)

The formula for Sulfuric acid is H2SO4.

The result ( aluminium sulfate ) is Al2(SO4)3. Aluminium has an oxidation number of +3, SO4 has an oxidation number of -2 ( S(+6) + 4O (4x-2) : 6-8 = -2

So we have to multipy aluminium 2x and SO4 (3x) to equal.

On the right side we have 3x S, so on the right side we have to multiply H2SO4 also by 3 to get the same amount.

This results in 12x Oxygen (3xO4). Which is the same as the right side.

On the left side we have 6H ( 3xH2) so on the right side we multiply H2 by 3 to get the same amount.

So we have on both sides:

2x Al

6xH

3xS

12xO

Answer:

Mitosis is common to all eukaryotes; during this process, a parent cell splits into two genetically identical daughter cells, each of which contains the same number of chromosomes as the parent cell.During meiosis, the cells needed for sexual reproduction divide to produce new cells called gametes.

Answer:

They contain copies of the same cellular components.

They are exact copies of one another.

Explanation:

i just got the answers

Answer:

The given graph in the question shows relation between melting point and boiling point of the given substance.

Explanation:

The above given graph shows Direct proportionality between melting point and boiling point that is with the decreasing of melting point, the boiling point is also decreasing. Hence the proportionality is shown between the two temperatures of boiling and melting in the given graph.

Answer:

The frequency of wave is 0.125 Hz.

Explanation:

Frequency:

"It is an event repeat itself in a given period of time"

The unit of frequency is the Hz . If time is measured in seconds then frequency will be in Hz. Hz is equal to the per second.

Formula:

f = 1/ T

f = 1/ 8 sec

f = 0.125 Hz