how many valence electrons does each of these four elements have? how do you know? a) aluminum (al), b) fluorine (f), c) sodium (na), and d) calcium (ca)

The statement that best describes why NASA crashed DART into an asteroid is  option A; NASA wanted to know if crashing a satellite into an asteroid would be enough to change the course of the asteroid.

Double Asteroid Redirection Test is the name of the first "planetary defense" test that the US space agency, in collaboration with researchers at Johns Hopkins University, carried out to determine whether it was possible to change the course of an asteroid in deep space if one ever got close enough to threaten Earth.

The 'planetary defense' experiment on the Dart mission seeks to determine whether Armageddon-style impacts can be avoided.

Therefore, The world's first planetary defense technology demonstration, NASA's Double Asteroid Redirection Test (DART), successfully impacted its asteroid target on Monday after spending 10 months in space. This was the agency's first attempt to move an asteroid in orbit.

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Answer: convection

Explanation:

Answer:

The moon reflects the light from the sun

Explanation:

Answer:

it reflects light from the sun

Explanation:

The solution has a 0.114 M molar concentration.

Using the formula, we can determine the molar concentration from the weight percentage of the solution;

CM = 10 C%w/w d/MM

Where;

Molar concentration is CM,percent concentration C%w/w,Density is d,M = molecular mass.

In place of values, we have;

CM = 10 × 0.85 × 1.0 /74.44

CM = 0.114 M

A solution is a specific kind of homogenous mixture made up of two or more components that is used in chemistry. A solute is a substance that has been dissolved in a solvent is solution , which is the other substance in the mixture.Concentration is calculated by dividing a constituent's abundance by the mixture's total volume. One can distinguish between four different sorts of mathematical descriptions: mass concentration, molar concentration, number concentration, and volume concentration.

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Answer:

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What happens to electrons when an ionic bond forms?

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It is the prior distribution of electrons that constitutes the electrostatic force of interaction..

Explanation:

Commonly, ions are formed by (i) the loss of electrons from metals... electron rich materials from the left of the Periodic Tables as we face the Table, whose valence electrons are furthest removed from the positively charged nuclear core... and (ii) the gain of electrons by non-metals to the right of the Periodic Table as we face it.

We could represent these processes by the reaction...

M→M

n+

+ne

−

oxidation

X+e

−

→X

−

reduction

We add the two redox processes together in such a way that the electrons are eliminated as virtual particles and we get a neutral salt... of a material and a non-metal that are held together by a strong electrostatic force of attraction...

M+nX→MX

n

And thus the electrons are formally redistributed to give positive and negative ions that combine to form NEUTRAL SALTS.

Answer:

The answer to your question is,

A. true

Explanation:

I hope this helps

I am sorry if I am wrong

As we know that, bond polarity and  the ionic character of any compound increases with raise in the difference of the electronegativity.

The percentage of ionic character of the bond increases with δen. An arbitrary value of 50% ionic character separates ionic from covalent bonding.

What does covalent bonding explain?

When two or more atoms share one or more pairs of electrons, a covalent bond is formed. These electrons are attracted to two neutrons and protons simultaneously. A covalent bond is formed when the difference between the electrical configurations of two atoms is too small for an electrochemical reaction to occur and ions to be produced.

What properties do covalent bonds have?

Bonds between atoms in covalent compounds share electrons. They have distinct physical properties, such as lower melting points and electrical conductivity than ionic compounds, due to the sharing of electrons.

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The features of the Earth that most directly contribute to the climate observed in Western Sahara are:

Climate is an area's long-term weather trend, often averaged over 30 years.

More precisely, it is the average and variability of climatic variables across temporal periods ranging from months to millions of years.

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If the ionic constant Q is greater than Ksp the solution forms precipitate if it is lower than the solubility constant Ksp then there will be no precipitate. Both of the given solutions forms precipitate.

The ionic constant Q of a solution is the product of molar concentrations of reactants. Solubility constant Ksp is the product of solubilities of the reactant ions when the reaction is in equilibrium.

For the first solution Q = 0.020 M × 0.015M  = 0.003.

Ksp  = 0.000001. Hence, Q is greater than Ksp which means the solution forms precipitate of BaF₂.

For the second solution Q = 0.035 M × 0.15 M =0.0025.

This is greater than Ksp = 1.6 × 10⁻⁵. Hence, this solution forms a precipitate of PbCl₂.

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If the work done by the expanding gas equals the heat added, despite the constant energy of the system of the gas, the temperature can stay constant.

An ideal gas is one where there were no inter - molecular attraction forces and all collisions involving atoms and molecules are entirely elastic. It can be seen as a group of perfectly nearly spherical that collide but do not otherwise interact with one another.

Temperature doesn't vary, but pressure and volume do. The energy content will not change throughout this procedure because there is no exchange of labor or heat with the environment. As a result, a perfect gas's internal energy depends solely on its temperature.

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A buffer can not be made from  a strong acid and a salt.

We know that the term buffer has to do with the type of solution that we use to prevent any kind of change in the acidity or the alkalinity of a solution. In order words, the buffer is the type of solution that is used to prevent a change in the pH of the system.

Unfortunately, there can not be a buffer that is made from a strong acid and a strong base. Rather we can only have a buffer that is made from a weak acid and its salt  or a buffer that is made from a weak base and its salt.

Since HCl is  a strong acid and NaCl is a salt of  strong acid, it then follows that the combination of HCl and NaCl can never be used as a buffer.

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a) the Dutch process at the molecular level Pyrol and benzyl alcohol do not react with NaOH.

b) The molecules are ranked from those that are least likely to be present after the Dutch process to those that are most likely to be present after the Dutch procedure Pyrrol is more likely to be present than butyric acid, which has a lower likelihood of being there.

c) Butyric acid's carboxylic acid is removed using NaOH.

The acidic chemicals with a bitter taste are washed in the Dutch procedure using a strong base like NaOH. Basic substances are not cleansed and only very acidic substances are washed thoroughly. However, vanillin is only somewhat acidic, thiophenol is less acidic, butyric acid is acidic, benzyl alcohol is neutral, and pyrrol is basic.

a) Benzyl alcohol and pyrrol do not react with NaOH. However, butyric acid combines with it to produce sodium butyrate (CH₃CH₂CH₂COONa), vanillin creates its sodium salt ((2-OCH₃,4-CHO)C₆H₃ONa), and thiophenol creates sodium benzenethiolate (C₆H₅SNa).

b) Butyric acid is least likely to be present and pyrrol is most likely to be present. Butyric acid is followed in increasing order of presence by vanillin, thiophenol, benzyl alcohol, and pyrrole.

c). NaOH is used to wash away the carboxylic acid in butyric acid. Due to the aromatic ring, vanillin and thiophenol are acidic and combine with NaOH to generate a sodium salt that is water soluble. Because it is neutral and pyrrole is basic, neither benzyl alcohol nor pyrrole will react with NaOH.

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Answer:

5.0 L

Explanation:

Wegener suggested that the deserts of Africa were once covered in ice and that the striations were formed by the movement of the ice across the desert floor.

Glacier striations are grooves or scratches in the bedrock that have been created by a glacier sliding over the surface. They are typically found in areas where the ice has melted away, revealing the bedrock beneath.

Wegener suggested that the deserts were once wetter and lusher. He proposed that the climate has gradually changed over time, making the deserts arider. This is supported by evidence of ancient riverbeds and lakes in the Sahara Desert.

Glacier striations can be used to help researchers learn about the history of a particular glacier and the climate in the area where it is located. For example, the direction of the striations can indicate the direction the glacier was moving and the depth of the striations can give clues about how deep the glacier was.

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The conclusion would be that Rf value is wrong.

Rf value refers to the retention factor. It is used in Thin Layer Chromatography, which is the technique to identify molecules based on their polarity. The. rf value is the ratio of distance travelled by solute to the distance travelled by solvent.

Solute can not move faster than solvent, hence, the distance travelled is always less. This means that numerator will be less than denominator making it less than 1. In general, the rf value lies between 0 and 1. Therefore, there is something wrong in the experiment.

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Whether they are polar or nonpolar, all molecules exhibit dispersion forces. Atoms and molecules that are bigger and heavier show larger dispersion forces than those that are smaller and lighter.

Look for the molecule with the most polarity, the most electronegative atoms, or the most hydrogen bonding groups if the molecules have identical molar weights and similar intermolecular forces. That one will have the overall stronger IMFs.

Each pair of molecules is as identical as possible except for the fact that one is polar and the other is nonpolar. The polar substance always has the higher boiling point, which denotes stronger attraction forces, or stronger intermolecular forces, between individual molecules.

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The most accurate method of weighing for this student to obtain the mass of crude acetanilide without pre-weighing is by taking the difference between weights of the crude acetanilide with the flask and the empty flask.

What are some of the different ways of weighing compounds in laboratory?

The most accurate way of weighing the crude acetanilide without pre-weighing is to weigh the crude acetanilide with the Erlenmeyer flask and then empty it completely and weigh the empty flask again. Then calculate the difference to get the mass of crude acetanilide.

Therefore, the weighing by difference method can be used to measure the weight of the crude acetanilide.

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The volume inside a deodorant can is 0.199 L.

Charles’s law applies when a fixed amount of gas is in a container and the pressure is constant if the temperature increases the volume of gas also increases. The formula

[tex]\frac{V_1}{T_1} = \frac{V_2}{T_2}[/tex]

The temperature units have to be in Kelvin. Volume units can be anything as long as both volume has the same units.

When a container is heated, the gas in it will experience a temperature increase and the volume of the gas will expand. But the expansion will not exceed the contents of the container.

[tex]\frac{V_1}{T_1} = \frac{V_2}{T_2}[/tex]

[tex]\frac{V_1}{298} = \frac{0.25}{373}[/tex]

V1 x 373 = 298 x 0.25

[tex]V_1 = \frac{74.5}{373}[/tex]

V1 = 0.199 L

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The molar concentration of acetic acid in vinegar is 64.62 M

Titration is known as the quantitative concentration of a given solution. It is also known as the quantitative analysis.

In the given condition we have 33.38ml of 0.1936 molar of NaoH solution to titrate 10ml of HC2H3O2.

Therefore,

HC2H3O2 + NaoH - H2O + NaC2H3O2

       The concentration of the given base (NaoH) = 0.1936 molar.

        The volume of the given bae = 33.38ml.

         The volume of acetic acid = 10ml.

We can denote the concentration and volume of the given samples as,

Ca = concentration of acetic acid

Cb = concentration of the base( NaoH)

Va = volume of acetic acid

Vb = volume of base.

      By putting the value in equation, we get

Ca x Va = Cb x Vb

since, we need to find Ca, we need to shift the Va to the right-hand side.

Therefore,

Ca = Cb x Vb/ Va

Substituting the values we get,

Ca= 0.1936 x 33.38/ 10

Ca = 64.62 M

  Therefore, the molar concentration of acetic acid is 64.62M

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Energy levels are the fixed distances of electrons from the nucleus, sublevel is a level that is lower than another level whereas an orbital is the most likely location of an electron present around an atom.

The sublevels contain carry orbitals. Orbitals are spaces that have a high prospect of containing an electron. An orbital is an area or location where the electrons are present. There can be two electrons in one orbital extreme. Each energy level or shell is divided into many sublevels. Both sublevel and subshell are used interchangeably. The sublevels are constituted by the letters s, p, d, and f. Each energy level has certain sub-levels. Therefore, these circular orbits are called as energy levels or energy shells. The orbits of an atom act for the energy levels of the electrons in it.

So we can conclude that Orbitals and sublevels are both concepts used in chemistry to describe the energy states of electrons.

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The equation which represents sublimation in the given option is,

H2O(s) → H2O(g).

What is sublimation?

Sublimation is the process of the conversion of substance in solid state directly to gaseous state without going to the liquid state. An example for sublimation is dry ice which is also called as solid carbon dioxide. At ordinary temperature, dry ice gets converted from solid to gaseous form without going through the liquid state.

In sublimation process, the water is in the solid state which is getting converted into the gaseous state which is water vapor. In water, the snow or ice change directly to vapour from solid form.

Hence, water getting converted from solid state to gaseous state is the  sublimation process. Here H2O (s) is getting converted into H2O (g). Therefore, option 2 is the correct answer.

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Answer:

The liquid radiation targets cancerous cells while causing minimal damage to surrounding healthy cells.

Answer: 10

A cup of coffee has a hydroxide ion concentration of 1. 0 × 10−10 m. The pH of this coffee will be 10

pH = - log [H+]

    = - log [1. 0 × ]

    = - log 1 - ( -10 log 10 )

    = 0 + 10  = 10

The pH of this coffee will be 10

Explanation:

Strong bases and weak acids in salts do hydrolyze, raising the pH level over 7. The anion in salt comes from a weak anion.

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Answer:

Argon Gas

Explanation:

:)

Answer:

NH3 is the limiting reactant; 51 g of excess reactant left over.

Explanation:

First, create the chemical equation for this reaction and balance it:

4NH3 + 5O2 ---> 4NO + 6H2O

Then, find the limiting reactant, but in this case using NH3:

75 g NH3 * 1mol NH3/17.04 g NH3 *  5 mol O2/4 mol NH3 * 18.02 g 02/ 1 mol O2 = 99.14 g O2 needed

Since 99.14 g of O2 is needed to react with 75 g of NH3, this means O2 is the excess reactant, since we have 150 g of O2 which is more than needed. This means that NH3 is the limiting reactant.

To find the mass of excess reactant left over, subtract the mass of O2 needed (99.14 g) from the mass used in the reaction (150 g).

150 g - 99.14 g = 50.858 g

Round to the appropriate number of sig figs:

50.858 g --> 51 g

Answer:

1.12 x 10⁻⁵ grams H₂O

Explanation:

To find the mass of water, you need to use the following equation:

Q = mcΔT

In this equation,

-----> Q = heat (J)

-----> m = mass (g)

-----> c = specific heat capacity (J/g°C)

-----> ΔT = T₂ - T₁ = change in temperature (°C)

"T₁" represents the initial temperature and "T₂" represents the final temperature. The specific heat capacity of water is 4.186 J/g°C. Before plugging the variables into the equation and solving for "m", you need to convert the energy from kilojoules (kJ) to joules (J).

1,000 kJ = 1 J

Q = 2.19 kJ / 1,000 = 0.00219 J         c = 4.186 J/g°C

m = ? g                                                 ΔT = 74.5°C - 28.0°C = 46.5°C

Q = mcΔT                                                   <----- Given equation

0.00219 J = m(4.186 J/g°C)(46.5°C)          <----- Insert variables

0.00219 J = m(194.649)                             <----- Multiply 4.186 and 46.5

1.12 x 10⁻⁵ = m                                            <----- Divide both sides by 194.649

11.25 grams of water can be heated from 28.0°C to 74.5°C when 2.19 kJ of heat is absorbed.

The specific heat is the amount of heat per unit mass required to raise the temperature by one degree Celsius.

It is a measure of how much energy it takes to raise the temperature of a substance. It is the amount of heat necessary to raise one mass unit of that substance by one temperature unit.

It is given by the formula -

                                                  Q = mcΔT

where, Q = amount of heat

m = mass

c = specific heat

ΔT = Change in temperature

Given,

Amount of heat = 2.19kJ

Initial Temperature = 28

Final Temperature = 74.5

Q = mcΔT

2190 = m × 4.18 × ( 74.5 - 28 )

m = 11.25 g

Therefore, 11.25 grams of water can be heated from 28.0°C to 74.5°C when 2.19 kJ of heat is absorbed.

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12 moles of H₂ need to produce 8 moles of NH3 if you have plenty of N₂ .

What is a chemical reaction ?

Chemical reaction, the process by which one or more substances (reactants) are transformed into one or more other substances (products). Substances are either chemical elements or compounds. Chemical reactions rearrange the constituent atoms of reactants to produce different substances as products.

Chemical reactions are  part of technology, culture, life . Fuel combustion, glass and pottery making, beer , and wine and cheese making are few examples. Activities involving chemical reactions that have been around for thousands of years. Chemical reactions are abundant in a variety of complex processes occurring in the Earth's geology, atmosphere and oceans, and in all biological systems.

The balanced chemical equation is:

N2+3H2→2NH3

From stoichiometry,

2 mol of NH3

is produced from 3 mol of H2

8 mol of NH3 will be produced from = 3/2×8=12 mol of H2

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The correct mole ratio of the reaction is 1 mol of carbonate to 2 mol of acid. Option B

We know that the ratio of the reactants that are involved in a reaction is what we call the mole ratio. We have to note that a neutralization reaction is the type of reaction that occurs between an acid and a base. We also have to recall that is vita to be able to write the balanced reaction equation before we can be able to find the mole ratio.

Now, we have the balanced reaction equation as;[tex]CO_{3} ^2-(aq) + 2H^+(aq) ----- > H2O(l) + CO2(g)[/tex]. The reaction is thus a 1:2 reaction for the carbonate and acid.

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so we have  to calculate the average mass of the SLAP

given,

percentage abundance of 2H= 0.008917%

mass of 2H= 2.01410 amu

mass of 1H= 1.00782 amu

now we calculate, the percentage abundance of 1H = 100% - 0.008917%

                                                                                 = 99.991%

the average mass of SLAP = percentage abundance of 1H x mass of 1H +      percentage abundance of 2H x mass of 2H

= 99.991% x 1.00782 + 0.008917% x 2.01410

=(99.991x1.00782)/ 100 +( 0.008917)x2.01410/100

= 1.00773 + 0.000173

= 1.0079 amu

the average mass of SLAP is 1.0079 amu

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