39. Which of the following conversion factors would you use to change 18 kilometers to meters?
A. 1000 m/1 km
B. O1 km 1000 m
C. 100 m 1 km
D. 1 km 100 m

Answer: 5

Explanation: nitrogen has atomic number of 7 and its electronic configuration is 2, 5.

5 is the number of electrons in the outermost shell

Answer:

Phosphorus

Explanation:

As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction and electronegativity increases.

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus electronegativity decreases.

Silicon is present in group 4A and Phosphorus and Arsenic is present in group 5A thus electronegativity of silicon is less than Phosphorus and arsenic. Arsenic is present down to phosphorus thus its electronegativity will less than phosphorus.

P = 2.19

Si = 1.9

As = 2.18

Answer:

A. 170.24 dm³

B. 9.9 dm³

C. 80.6 dm³

Explanation:

Data Given:

no. of moles of Ar = 7.6 mol

no. of moles of C₂H₆ = 0.44 mol

no. of moles of NH₃ = 3.6 mol

Volume of each gas at STP = ?

Solution:

To calculate volume of gas at STP (Standard temperature and pressure) formula will be used

             no. of moles = volume of gas / molar Volume

Rearrange the above equation:

              Volume of gas = no. of moles x molar Volume . . . . . . (1)

where

molar volume at STP = 22.4 dm³/mol

• A. Now to calculate Volume for 7.6 mole Ar

Put value in equation 1

Volume of Ar = 7.6 mol x 22.4 dm³/mol

Volume of Ar = 170.24 dm³

___________

• B. Now to calculate Volume for 0.44 mole C₂H₆

Put value in equation 1

Volume of C₂H₆ = 0.44 mol x 22.4 dm³/mol

Volume of C₂H₆ = 9.9 dm³

___________

• C. Now to calculate Volume for 3.6 mole NH₃

Put value in equation 1

Volume of NH₃ = 3.6 mol x 22.4 dm³/mol

Volume of NH₃ = 80.6 dm³

The volume of the gases at Standard Temperature and Pressure (STP) can be calculated using Avogadro's law. For 7.6 mol of Ar, the volume is 170.24 L. For 0.44 mol of C2H6, the volume is 9.856 L and for 3.6 mol of NH3, the volume is 80.64 L.

To calculate the volume of a gas at Standard Temperature and Pressure (STP), you can use Avogadro's law which states that one mole of any gas will occupy a volume of 22.4 liters.

The calculated volumes of the gases are:

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Answer:

Explanation:

Balanced Chemical equation:

HClO₂(aq) + NaOH(aq) → H₂O(l) + NaClO₂ (aq)

Ionic equation:

H⁺(aq) + ClO₂⁻(aq) + Na⁺(aq) + OH⁻(aq) → H₂O(l) + Na⁺(aq) + ClO₂⁻ (aq)

Net ionic equation:

H⁺(aq) + OH⁻(aq) → H₂O(l)  

The ClO₂⁻(aq) and Na⁺ (aq) are spectator ions that's why these are not written in net ionic equation. The water can not be splitted into ions because it is present in liquid form.

Spectator ions:

These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.  

Chemical equation:

NaCl(aq) + KBr(aq)  → NaBr(aq) + KCl(aq)

Ionic equation:

Na⁺(aq)  + Cl⁻(aq) + K⁺(aq)  + Br⁻(aq)  → Na⁺(aq) + Br⁻(aq) + K⁺(aq)  + Cl⁻(aq)

Net ionic equation can not be written for this reaction because nothing is changed on both side. There is no solid, liquid and gaseous product. All are aqueous and cancel each other.

Answer:

₈₆²²²Rn    →   ₈₄Po²¹⁸  +  H₂⁴

Explanation:

The given nuclear reaction shows alpha decay.

₈₆²²²Rn    →   ₈₄Po²¹⁸  +  H₂⁴

Properties of alpha radiations:

Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4  and atomic number less than 2 as compared to parent atom the starting atom.

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

₉₂U²³⁸   →   ₉₀Th²³⁴  + ₂He⁴  + energy

Final answer:

The radioactive decay of radon-222 emits an alpha particle, resulting in the formation of polonium-218. This process can be represented by the nuclear equation 222Rn → 4He + 218Po.

Explanation:

The question refers to the radioactive decay of radon-222. In this decay process, radon-222 emits an alpha particle (42He) and transforms into a different element. An alpha particle consists of 2 protons and 2 neutrons, which is why it's represented as 42He. The nuclear equation for this decay can be written as follows:

22286Rn → 42He + 21884Po

To balance the equation, you subtract the mass number and the atomic number of the alpha particle from those of the original radon-222 nucleus. This leaves us with an element that has an atomic number of 84 and a mass number of 218, which is polonium (Po). Therefore, the complete nuclear equation is:

222Rn → 4He + 218Po

Answer:

B

Explanation:

From the given formukar for energy of a photon, we can obtain the energy of the photon as shown in the image. The meaning of the parameters in the equation are also shown in the image.

Answer: 2.21 x 10^-18 j

Explanation: a pex

Answer:

parent and offspring

Explanation:

I think probably what the question is referring to is in the context of biology, the "original organism" is known as the parent. The young that they reproduce are known as the offspring.

The offspring could be formed by the sexual reproduction of two parental organisms, or the asexual reproduction of just one parental organism.

Answer:

Halogen group (group 17)

Hope it helps:)

Answer: false

Explanation: metal like sodium, potassium have just one oxidation number while metals like aluminium have 3

When atoms gain electrons they have more electrons, so they increase their size due to the energy levels, orbitals, etc. Those are the atoms that form negative ions. (Non Metals)

When atoms loose electrons and form positive ions they loose components and energy levels. Therefore they decrease their size.

The only one here who forms negative ions is Bromine (Br) that forms Bromide (Br-1)

So it will be answer B) Br

Final answer:

To calculate the mass of glucose produced from 3.00 moles of carbon dioxide in the photosynthesis reaction, use the mole ratio from the balanced equation and the molar mass of glucose (180.16 g/mol), which results in 90.08 grams of glucose.

Explanation:

The reaction 6CO₂(g) + 6H₂O(l) → C₆H1₁₂O₆(s) + 6O₂(g) represents the photosynthesis process where carbon dioxide and water produce glucose and oxygen. To find out the mass of glucose produced from 3.00 moles of carbon dioxide, we can use the mole ratio from the balanced chemical equation and the molar mass of glucose.

The balanced equation tells us that 6 moles of CO₂ produce 1 mole of glucose (C₆H₁₂O₆). Therefore, 3.00 moles of CO2 will produce half as much glucose, which is 0.5 moles of glucose. By using the molar mass of glucose, we can convert moles to grams.

For glucose, the molar mass is 180.16 g/mol. So,

Answer:

alloy is  metal made by combining two or more metallic elements, especially to give greater strength or resistance to corrosion.nation:

Explanation:

a combination of a metal with another element

Explanation:

3*2=6

12x+11=23x

23x+6=29x

x=2

Answer:

148x +7856y

Explanation:

The element XCI represented in Roman numerals corresponds to the atomic number of Protactinium. However, ΧΗ does not correspond to any known element in the periodic table.

The elements you've mentioned, X and ΧΗ, do not correspond to any known chemical elements in the periodic table. Chemical elements are typically represented by their chemical symbols, which are one or two letters derived from their English or Latin names. For example, "H" represents hydrogen, "O" represents oxygen, "C" represents carbon, and "Fe" represents iron.

It's possible that the symbols "X" and "ΧΗ" do not correspond to any naturally occurring elements or may not be recognized in the context of the periodic table. If you have more information or context regarding these symbols, please provide it, and I will do my best to assist you further.

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a.) Plants that thrive in the shade are often able to hold on to sunlight for extensive periods of time; they're in a sense like the camels of the plaNt WoRld.

b.) Though artificial lights are not nearly as beneficial as the sun, one could invest in one of them plant growing light thingies, but sun-loving plants might be sad if u do this instead of letting them soak in ePic rays from the sun.

Answer:

Separation method for various ingredients are

1. Paneer from curdled milk.  - Filtration

2. Chalk powder from water.  - Filtration

3. Sand from salt solution. - Evaporation

4. Saw dust from water.  - Skim off, sieve or filter

5. Tea leaves from brew. - Filtration.

Explanation:

By the help of a muslin cloth the paneer is separated from the curdled milk, the process is called as the filtration. The paneer will remain in the cloth and curdled milk will be removed. Separation of chalk powder from water is very easy by the process of filtration, after the filtration the chalk powder retentate and the filtrate obtained is the water in absence of chalk.  Salt and sand water separation can be done with the help of evaporation. Separation of the saw dust from water takes place by the method of sieving or sedimentation. The tea leaves are separated from brew by filtration.

Answer:

Explanation:

Data Given:

volume of SO₂ = 48.6 L

mass of H₂SO₄ = 200 g

balance equation = ?

theoretical yield = ?

percent yield = ?

Solution:

Part 1:

first we have to write a balance equation for the reaction

SO₂ gas react with water (H₂O) and excess oxygen

The balanced equation is as under

                       2SO₂ +  O₂ + 2H₂O  -----------> 2H₂SO₄

Part 2:

Now we have to find theoretical yield

First look at the balance reaction

                        2SO₂ +  O₂ + 2H₂O  -----------> 2H₂SO₄

                        2 mol                                         2 mol

2 moles of SO₂ give gives 2 moles of H₂SO₄

Now calculate volume of 2 moles of SO₂ and mass of 2 moles of H₂SO₄

volume of 2 moles of SO₂

Formula used

                 volume of gas = no. of moles x molar volume . . . . . . (1)

molar volume of SO₂= 22.4 L/mol

Put values in above formula (1)

                 volume of gas = 2 mol x 22.4 L/mol

                 volume of gas = 44.8 L

volume of 2 mole of SO₂ = 44.8 L

Now,

Find mass of 2 mole H₂SO₄

Formula Used

            mass in grams = no. of moles x molar mass . . . . . . . (2)

molar mass of H₂SO₄ = 2 (1) + 32 + 4(16)

molar mass of H₂SO₄ = 98 g/mol

put values in equation 2

        mass in grams = 2 mol x 98 g/mol

        mass in grams = 196 g

mass of 2 mole of H₂SO₄ = 196 g

** So,

Now we come to know that

44.8 L of SO₂ gives 196 g of H₂SO₄ then how many grams of the H₂SO₄ will be produced by 48.6 L of SO₂

Apply unity Formula

               44.8 L of SO₂ ≅ 196 g of H₂SO₄

               48.6 L of SO₂ ≅ X g of H₂SO₄

Do cross multiplication

                g of H₂SO₄  = 196 g x 48.6 L / 44.8 L

                g of H₂SO₄  =  213 g

So that is why the theoretical yield of H₂SO₄ is 213 g

Theoretical yield of H₂SO₄ = 213 g

Part 3

Calculate Percent Yield:

Formula used for this purpose:

             percent yield = actual yield /theoretical yield x 100 %

Put value in the above formula

           percent yield = 200 g/ 213 g x 100 %

          percent yield = 94 %    

So percent yield of H₂SO₄ = 94 %    

Answer:

 (NH₄)₃PO₄ (l) + Al(NO₃)₃(l) -----------→  AlPO₄(l) + 3NH₄NO₃(l)

Explanation:

Data Give:

Reaction between ammonium phosphate solution and solution of aluminum nitrate

Details:

To write a balanced chemical equation we have to know formula units of compounds or molecules

Formula units

ammonium phosphate : (NH₄)₃PO₄

aluminum nitrate: Al(NO₃)₃

ammonium nitrate: NH₄NO₃

Now to write a chemical equation

So the Reaction will be

                      (NH₄)₃PO₄ + Al(NO₃)₃ -----------→  AlPO₄ + NH₄NO₃

Now balance the Chemical equation

                     (NH₄)₃PO₄ + Al(NO₃)₃ -----------→  AlPO₄ + 3NH₄NO₃

Now write the phase Symbols

                     (NH₄)₃PO₄ (l) + Al(NO₃)₃(l) -----------→  AlPO₄(l) + 3NH₄NO₃(l)

all compounds in the reaction are in liquid form and soluble in water

*** Note:

There is no aluminum nitrite in chemicals formulas

Also ammonium nitrite can not be used in pure isolated form due to its highly instability

Answer:

dehydration process is occurring in this process.

Concentrated sulfuric acid sometimes used as drying agent because it has a very strong affinity for water and can be used to dehydrate means removal of water occur. Removing of water from reactant compound results in formation of double bond in product compound.

The given reaction involves the dehydration of ethanol ([tex]CH_3CH_2OH[/tex]) in the presence of sulfuric acid ([tex]H_2SO_4[/tex]) and heat, resulting in the formation of ethylene ([tex]CH_2CH_2[/tex]). This type of reaction is known as an elimination reaction. Specifically, it is a dehydration reaction, where water ([tex]H_2O[/tex]) is removed from the starting material to form the product.

The reaction described involves the dehydration of ethanol ([tex]CH_3CH_2OH[/tex]) in the presence of sulfuric acid ([tex]H_2SO_4[/tex]) and heat, resulting in the formation of ethylene ([tex]CH_2CH_2[/tex]).

Dehydration reactions are a type of elimination reaction where a molecule of water is removed from the starting material to form a new compound.

In this case, the hydrogen and hydroxyl (OH) groups from adjacent carbon atoms in ethanol are eliminated to form a double bond between the carbon atoms, resulting in the formation of ethylene.

Sulfuric acid acts as a catalyst, facilitating the removal of the water molecule from the ethanol molecule. The heat provides the energy required to drive the reaction forward.

Overall, this reaction is an example of a chemical transformation that involves the removal of water to form a new compound.

Answer:

A is Sediments

B  is metamorphic rock

C is sedimentary rocks

D is weathering

Explanation:

A represent smaller particles of rocks known as sediments. From the picture above sedimentary rocks, igneous rocks and metamorphic rocks were broken into smaller constituent due to events like weathering(D). Weathering disintegrated these rocks into smaller particles (sediments).

B is rock known as metamorphic rocks. Metamorphic rocks are formed from igneous, sedimentary or even metamorphic rocks. The major factor behind metamorphic rocks formation is temperature and pressure. Generally, the parents rocks never melts, the transformation usually occur in a solid state. Metamorphism is a process that is usually accompanied with change in mineral assemblage , physical attribute of the rocks or both. From the picture above the sedimentary rocks(C) was converted to metamorphic rocks due to temperature and pressure . Same occurrence was present in the conversion of igneous rocks to metamorphic rocks(B)

C is a sedimentary rocks. Sedimentary rocks are formed from smaller particles of the weathered rocks.  The smaller particles are known as sediments. This sediments are then cemented and compacted by cementing agents to form sedimentary rocks.

D is a process, which is known as weathering. Weathering is the disintegration of rocks into smaller particles to form sediments . Weathering may involve change in the chemical composition of rocks or  just a physical change . From the picture above igneous rocks, metamorphic rock and sedimentary rocks were weathered to form sediments(A).

Answer:

Explanation: i got 100% on edge.

Answer:

They require only one electron to complete their outer shell

Explanation:

The elements of group 17 are called halogens. These are six elements Fluorine, Chlorine, Bromine, Iodine, Astatine. Halogens are very reactive these elements can not be found free in nature. Their high reactivity is due to the presence of seven valance electrons. They need just one electron to complete the octet that's why they can not found free in nature. Their chemical properties are resemble greatly with each other. As we move down the group in periodic table size of halogens increases that's way fluorine is smaller in size as compared to other halogens elements. Their boiling points also increases down the group which changes their physical states. i.e fluorine is gas while iodine is solid.

Consider the example of sodium chloride. Chlorine accept one electron from sodium and complete the octet.

The electronegativity of chlorine is 3.16 and for sodium is 0.93. There is large difference is present. That's why electron from sodium is transfer to the chlorine. Sodium becomes positive and chlorine becomes negative ion. Both atoms are bonded together electrostatic attraction occur between them and both get complete complete octet.

Answer:

1) have a high electronegativity

and

2) require only one electron to complete their outer shell

Explanation:

Answer:

A. 4 Al + 3 O2 —> 2 Al2O3

Explanation:

4Al + 3O2 —> 2Al2O3

There are four aluminium and six oxygen atoms on both side of equation so this equation follow the law of conservation of matter.

Law of conservation of mass:

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

Explanation:

This law was given by french chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

For example:

In given photosynthesis reaction:

6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂

there are six carbon atoms, eighteen oxygen atoms and twelve hydrogen atoms on the both side of equation so this reaction followed the law of conservation of mass.

Final answer:

Option A correctly illustrates the conservation of matter as the chemical equation is balanced with 4 aluminum atoms and 6 oxygen atoms on each side, adhering to the principle that matter is neither created nor destroyed in a chemical reaction.

Explanation:

The conservation of matter is a principle in chemistry that states matter is neither created nor destroyed in a chemical reaction. To illustrate this, we examine the chemical equations provided to see if they are balanced—that is, if they have the same number of each type of atom on both sides of the equation.

Therefore, option A – 4 Al + 3 O2  —> 2 Al2O3 – correctly illustrates the principle of conservation of matter because the reaction is balanced with equal numbers of atoms on both sides of the equation.

Answer:

1.524 is 5ft to meters

Explanation:

Explanation:

The retention of analytes in gas chromatography can be increased by selecting mobile phase that is a weaker solvent. When the mobile phase has a lower solvent strength, solutes spend proportionally more time in the stationary phase and take longer to elute.

To find the average time for multiple trials of a car traveling a distance, sum the times and divide by the number of trials, then record these averages to two decimal places.

Calculating Average Time and Speed

To calculate the average time it takes a car to travel certain distances with washers attached to a pulley, you need to record the time it takes to travel those distances multiple times. Then, sum these times and divide by the number of trials to find the average. For example, if you measure the time it takes a car to travel 0.25 meters four times and get times of t1, t2, t3, and t4 seconds, the average time would be calculated as (t1 + t2 + t3 + t4) / 4. The process is similar for calculating the average time for 0.50 meters. Once you have these averages, you can record and round them to two decimal places for inclusion in Table C of the Student Guide.

The procedure also involves plotting a 'Distance vs. Time' graph from the recorded data and finding the gradient for the straight line through the data points, which yields the average velocity of the car.

Answer:

0.106 mol (3s.f.)

Explanation:

To find the number of moles, divide the mass of glucose (in grams) by its Mr. Glucose has a chemical formula of C6H12O6. To find the Mr, add all the Ar of all the atoms in C6H12O6.

Ar of C= 12, Ar of H= 1, Mr of O= 16

These Ar values can be found on the periodic table.

Mr of glucose= 6(12)+ 12(1) + 6(16)= 180

Moles of glucose

= mass ÷ mr

= 19.1 ÷ 180

= 0.106 mol (3 s.f.)

Answer:

I₂ + H₂O --------→ HI + HIO

Explanation:

Iodine is not fully dissolve in water but only dissolve up to some extent.

When iodine was mixed with water it give mixture of two products.

So the balance reaction is as under

        I₂ + H₂O --------→ HI + HIO

All the reactant are one mole and one one mole of each product produced in the shown reaction.

This is a reversible reaction and only 0.05% of Iodine molecule react with water and the other  Iodine molecule remain in water unreacted.

Answer:

gamma ray

Explanation:

Gamma emission results in the release of energy without any apparent change in mass or nuclear charge.

Properties of Gamma radiations:

Gamma radiations are high energy radiations having no mass.

These radiations are travel at the speed of light.

Gamma radiations can penetrate into the many materials.

These radiations are also used to treat the cancer.

Lead is used for the protection  against gamma radiations because of its high molecular density.

The lead apron are used by the person when treated with gamma radiations.

Lead shields are also used in the wall, windows and doors of the room where gamma radiations are treated, in-order to protect the surroundings.

Answer:

gamma ray

Explanation:

Answer:

7.5 m/s²

Explanation:

Given data:

Force on object = 418 N

Mass of object = 56 kg

Acceleration rate = ?

Solution:

Definition:

The acceleration is rate of change of velocity of an object with respect to time.

Formula:

a = Δv/Δt

a = acceleration

Δv = change in velocity

Δt = change in time

Units:

The unit of acceleration is m.s⁻².

Acceleration can also be determine through following formula,

F = m × a

a = F/m

Now we will put the values.

a = 418 N/ 56 kg

N = Kg. m /s²

a = 418 Kg. m /s²/ 56 kg

a = 7.5 m/s²