In a molecule of calcium sulfide, calcium has two valence electron bonds, and a sulfur atom has six valence electrons. How many lone pairs of electrons are present in the Lewis structure of calcium sulfide?
A. one
B. two
C. three
D. four
E. none

Answer:

1. solute dissolved in solvent makes up a solution.

Explanation:

Kendrick gave the bat potential Energy

Answer:

0.97 atm.

Explanation:

From the question given above, the following data were obtained:

Final pressure (P2) = 6.8 atm

Initial temperature (T1) = 40 K

Final temperature (T2) = 280 K

Initial pressure (P1) =?

Thus, we can obtain the initial (original) pressure of the gas as follow:

P1/T1 = P2/T2

P1 /40 = 6.8/280

Cross multiply

P1 × 280 = 40 × 6.8

P1 × 280 = 272

Divide both side by 280

P1 = 272/280

P1 = 0.97 atm

Therefore, the original pressure of the gas is 0.97 atm.

Answer:

5

Explanation:

An alkyl group is a functional group that contains only hydrogen and carbon atoms. It has the general formula: CnH2n+1.

Since n=2, plug it into the formula.

C2H2(2)+1

=

C₂H₅

Hope that helps.

Answer:

transform battery

Explanation:

Answer: D. Transform Boundary

Explanation: I did the test.

Answer:

Diamond

Explanation:

napthalene: C10H8 sulphur: S02

Explanation:

C10H8

Answer:

c I think but that's only what i think

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 24.088×10²³ atoms of carbon are in sample containing 4.000 moles of carbon. The correct option is option B.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number.

Mathematically,

number of atoms/molecules/ formula units of carbon= number of moles of carbon × 6.022×10²³

number of moles of carbon= 4 moles

substituting all the given values in the above equation, we get

number of atoms/molecules/ formula units of carbon= 4 × 6.022×10²³

number of atoms/molecules/ formula units of carbon=2.4088×10²⁴ atoms of carbon

There are 2.4088×10²⁴ atoms of carbon

Therefore, 24.088×10²³ atoms of carbon are in sample containing 4.000 moles of carbon. The correct option is option B.

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Answer:

B

Explanation:

The second one is not balanced correctly.

2 NaOH + 2HNO3 → 2NaNO3 + 2 H20

I didn't notice this before but it can be balanced without the twos.

 NaOH + HNO3 → NaNO3 +  H20

It was still wrong. It needed to have the twos removed, not 2 more added. Adding two more isn't wrong, but it should be balanced without 2s if at all possible.

Answer:

Ksp = 2.4 * 10⁻⁵

Explanation:

The equation for the dissolution and dissociation of CaSO4 in water is given as: CaSO₄ ---> Ca²⁺ + SO₄²⁻

The expression for the Ksp of the dissociation equation above is:

Ksp = [Ca²⁺] [SO₄²⁻]

The molar ratio of the dissociated ions and the solute is 1 : 1, this means that every 1 mole of CaSO₄ that dissolves produces 1 mole of Ca²⁺ and SO₄²⁻ each

The molar solubility of a substance is the number of moles that dissolve per liter of solution.

molar solubility of CaSO₄ = number of moles /liter of solution

number of moles of CaSO₄ = mass/molar mass

molar mass of CaSO₄ = 136 g/mol

number of moles of CaSO₄ = 0.67/136 = 0.0049 moles

molar solubility of CaSO₄ = 0.0049 mol/ 1 L =  4.9 * 10⁻³ moles per liter

therefore, molar solubility of CaSO₄ = 4.9 * 10⁻³

Ksp = (4.9 * 10⁻³) (4.9 * 10⁻³)

Ksp = 2.4 * 10⁻⁵

Answer:

2.4 * 10^-5

Explanation:

Molar solubility of CaSO4  = 0 .67 g/L/136 g/mol = 4.9 * 10^-3 Mol/L

Given that;

CaSO4(s) -------> Ca^2+(aq) + SO4^2-(aq)

Hence, Ksp = [Ca^2+] [SO4^2-]

Where  [Ca^2+] =[SO4^2-]=s

Ksp = s^2

since s = 4.9 * 10^-3 Mol/L

Ksp = (4.9 * 10^-3 Mol/L)^2

Ksp = 2.4 * 10^-5

The gas is confined in 3.0 L container ( rigid container) ⇒ the volume remains constant when the temperature is increased from from 27oC to 77oC and therefore V1=V2 .

Ideal gas law is valid only for ideal gas not for vanderwaal gas. Ideal gas is a hypothetical gas. Vanderwaal gas can behave as ideal gas at low pressure and high temperature. Therefore the final pressure is 1,750 mmHg.

Ideal gas equation is the mathematical expression that relates pressure volume and temperature.

Mathematically the relation between Pressure, volume and temperature can be given as

PV=nRT

where,

P = pressure of gas

V= volume of gas

n =number of moles of gas

T =temperature of gas

R = Gas constant = 0.0821 L.atm/K.mol

At constant volume, the above equation can be rearranged as

P₁/T₁ = P₂/T₂

Substituting all the given values in the above equation, we get

1500 ÷300= P₂÷350

P₂ =1,750 mmHg

Therefore the final pressure is 1,750 mmHg.

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Answer:

The correct answer is B. Hypothesis

Explanation:

The spontaneous reactions are said to be exothermic in nature. Hence, option B is correct.

The type of reaction that has not been utilizing energy input output to the reaction system in order to favor the formation of product are termed as exothermic reaction.

The entropy has been the tendency of the randomness of atoms in the system, and the enthalpy has been the energy of the system.

With the spontaneous reaction, there has been an increase in the entropy of the system with the formation of the products, and a decrease in the enthalpy. The reaction forms no use of the input energy, and thereby cannot be endothermic in nature.

Therefore, the reaction that is exothermic tends to be spontaneous reactions. Hence, option B is correct.

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Answer:

Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment.

Explanation:

Hope this helps :)

(didn't get this from the internet)

The atomic number of this atom : 8

Given

Atomic model (attached)

Required

The atomic number

Solution

To determine the atomic number of an element, we can look at the number of electrons or the number of protons, because

atomic number = number of protons = number of electrons in neutral atoms

While the mass number is the number of neutrons + the number of protons located in the atomic nucleus

The charge of each of these atomic sub particles:

If we look at this atomic model, there are 8 electrons in the shell, consisting of 2 electrons in the first shell and 6 electrons in the second shell (which can also be called valence electrons)

Whereas in the atomic nucleus there are 8 protons and 10 neutrons

Answer:8

Explanation:

Answer:

Mass of solute = 0.0036 g

Explanation:

Given data:

Concentration of Cl⁻ = 15.0 ppm

Volume of water = 240 mL

Mass of Cl⁻ present = ?

Solution:

1 mL = 1 g

240 mL = 240 g

Formula:

ppm = mass of solute / mass of sample ×1,000,000

by putting values,

15.0 ppm = (mass of solute / 240 g) ×1,000,000

Mass of solute = 15.0 ppm ×  240 g / 1,000,000

Mass of solute = 0.0036 g

Answer:A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels (n) increases, so there is a greater distance between the nucleus and the outermost orbital.

Answer:

A higher effective nuclear charge causes greater attractions to the electrons, pulling the electron cloud closer to the nucleus which results in a smaller atomic radius. Down a group, the number of energy levels increases, so there is a greater distance between the nucleus and the outermost orbital.Explanation:

Answer:

An Exothermic Reaction , gives off more heat, and a little energy to its surroundings.

this can helps us figure out that the answer is , C, More heat is given off into its products.

Explanation:

Answer:

92.4%

Explanation:

The volume per cubic meter of sodium preoccupy by the sodium ions is

[tex]V_{Na} = n \times V[/tex]

where;

volume (V) of each Na atom   = [tex]\dfrac{ 4}{3} \pi r^3[/tex]

Radius of each ion = 97.3 pm = 97.3 × 10⁻¹²

no.of atoms in the sample n =  mass of the sample / ( molar mass / NA)

mass of the sample per cubic metre =  911 kg/m³

∴

[tex]V = \bigg [ \dfrac{4}{3} \pi r^3 \bigg ] \bigg [\dfrac{MN_A}{m} \bigg ][/tex]

[tex]V = \bigg [ \dfrac{4}{3} \pi (97.3 \times 10^{-12} )^3 \bigg ] \bigg [\dfrac{ (911 kg/m^3 (m^3))(6.023\times 10^{23})}{27.7 \times10^{-3}\ kg/mol } \bigg ][/tex]

V = 0.07643 m³

The fraction of available conduction electrons are;

= (1 - V)

= 1 - 0.07643

= 0.92357

≅ 92.4%

The element with the electron configuration, 1s2 3s2 3p6 3s2 3p6 3d6 4s2, will be iron.

In the electronic configuration of elements, the number of electrons possessed by the element is shared into the orbitals according to their energy levels.

The electrons are first shared in orbitals in the same energy level before pairing starts.

Also for neutral atoms, the number of electrons is equivalent to the number of protons. The number of protons in itself represents the atomic number of elements.

Thus, considering this electron configuration, 1s2 3s2 3p6 3s2 3p6 3d6 4s2; the total number of electrons in all the orbitals is 26. The element with the atomic number of 26 is iron.

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Answer:

B

Explanation:

it is B because in order to have kinetic energy the object has to be in motion, because if it wasnt in motion and sitting on the hill then it has potentail energy, hope this helps

Answer:

Force F = 20N .

Mass m = 2.0 kg

Initial velocity u = 0

acceleration, a = 10m/s  

2

t = 1 sec.

Now Refer to the attachment, See the free body diagram of the block.

Force works on the block:-

Weight, W = mg

W = 2 × 10

W = 20N (which is Downward)  

Normal force N = mg cos37

N = 20 × 0.80  

N = 16 N. (perpendicular & upward to the plane )

Here Applied Force, P = 20N (which is down along the plane)

Now For Final Speed, We know the formula:-

v = u + at

v = 0 + 10 × 1

v = 10 m/s

the Distance travelled s = ut + 0.5 at×t

s = 0 + 0.5 ×10×1×1

s = 5 m.

Now,

(a)     So work done by the force of gravity in 1 sec. = F × d

             ⇒20 N × 5m      

             ⇒100 J.

(b) Here the weight act as downward, so distance travelled in downward.

             ⇒5 × sin37

             ⇒5 × 0.6  

             ⇒3 m.

so work done by gravity,

               ⇒20 N × 3 m

              ⇒60 J.

(c) Now, work done by all the forces  

               ⇒change in Kinetic energy

  ⇒

2

1  m(v2

−u  2

)

⇒0.5×2.0×(10  2

−0  2  )

⇒ 100 J.

⇒W.D by frictional force  

                 = work was done by all forces -( work was done by Normal force + work done by applied force + work done by gravity )  

                 = 100 J - (100 + 60 +0 )

                 = 100 - 1

     Hope this helps you≅        

The equation is balanced. There are 4 aluminium atoms and 6 oxygen atoms on each side.

Answer:

One orientation

Explanation:

A s orbital is a sphere like shape that surrounds the atomic nucleus that consists of electrons that can be found at the highest or lowest region of the orbital. S orbitals only consist of "one orientation" and is commonly mistaken by the p orbital because the p orbital also consists of electrons that can be found the most.

Hope this helps.

Answer:

Roman numeral notation indicates charge of ion when element commonly forms more than one ion. For example, iron(II) has a 2+ charge; iron(III) a 3+ charge.

Explanation: