56. What would be the valence electrons of 14Si, 16S, 32Ge respectively?
A. 4, 2,2
B. 4, 6,8
C. 4, 6,6
D. 4,6,4​

Answer:

no

Explanation:

this experiment could not be replicated, because there are no specific measurements. the details would not be the same because it does not include the type of paper used nor the diameter, width or length. A guess of the measurements would be the only way to replicate this experiment but other then that, no you cannot.

Answer:

pOH = - log [molarity of OH-] = - log [ molarity of NaOH] , assuming full dissociation. Thus, pOH = - log ( 0.001) = - (-3) = 3. Thus, the pH of 0.001 mol/dm3 NaOH solution is 11.

Explanation:

Hope it'll help!

Answer:

changing while growing

Explanation:

Answer: the answer is a

Answer:

Two moles.

Explanation:

Sulphuric (sulfuric) acid [tex]\rm H_2SO_4[/tex] is a diprotic acid. When one mole of [tex]\rm H_2SO_4[/tex] molecules dissolve in water, two moles of [tex]\rm H^{+}[/tex] ions would be produced.

[tex]\rm H_2SO_4 \to 2\, H^{+} + {SO_4}^{2-}[/tex].

On the other hand, sodium hydroxide [tex]\rm NaOH[/tex] is a monoprotic base. When one mole of [tex]\rm NaOH[/tex] formula units dissolve in water, only one mole of hydroxide ions [tex]\rm OH^{-}[/tex] would be produced.

[tex]\rm NaOH \to Na^{+} + OH^{-}[/tex].

Note that [tex]\rm H^{+}[/tex] and [tex]\rm OH^{-}[/tex] react at a one-to-one ratio:

[tex]\rm H^{+} + OH^{-} \to H_2O[/tex].

As a result, it would take [tex]2\; \rm mol[/tex] of [tex]\rm OH^{-}[/tex] to react with the [tex]\rm 2\; mol[/tex] of [tex]\rm H^{+}[/tex] that was released when [tex]1\; \rm mol[/tex] of [tex]\rm H_2SO_4[/tex] is dissolved in water. Since one mole of [tex]\rm NaOH[/tex] formula units could produce only one mole of [tex]\rm OH^{-}[/tex], it would take [tex]\rm 2\; mol[/tex] of [tex]\rm NaOH[/tex] formula units to produce that [tex]2\; \rm mol[/tex] of [tex]\rm OH^{-}[/tex] for reacting with [tex]1\; \rm mol[/tex] of [tex]\rm H_2SO_4[/tex].

Answer:

0.756 J

Explanation:

Temperature change (delta T) = 0.855 degrees Celsius

Mass of water (m) = 0.2067 g

Specific heat capacity of water (c) = 4.28 J/g degrees C

Heat added = m * c * delta T

= (0.2067 * 4.28 * 0.855) J

= 0.756 J

Given question is incomplete. The complete question is as follows.

Balance the following equation:

[tex]H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + H_2O[/tex]

Answer: The balanced chemical equation is as follows.

[tex]2H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + 2H_2O[/tex]

Explanation:

When a chemical equation contains same number of atoms on both reactant and product side then this equation is known as balanced equation.

For example, [tex]H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + H_2O[/tex]

Number of atoms on reactant side:

H = 5

P = 1

O = 6

Ca = 1

Number of atoms on product side:

H = 6

P = 2

O = 9

Ca = 1

In order to balance this equation, we will multiply [tex]H_3PO_4[/tex] by 2 on reactant side and we will multiply [tex]H_2O[/tex] by 2 on product side. Hence, the balanced chemical equation is as follows.

[tex]2H_3PO_4 + Ca(OH)_2 \rightarrow Ca(H_2PO_4)_2 + 2H_2O[/tex]

Answer:

Here's what I get  

Explanation:

Sublimation is the conversion of a solid directly to a gas, without passing through the liquid state.

It occurs when the molecules of a solid have absorbed enough heat (kinetic energy) for some molecules to overcome the attractive forces of their neighbours and escape directly into the vapor phase.

One substance that sublimes at room temperature and pressure is CO₂ (dry ice).

Naphthalene is a substance that sublimes at room temperature and pressure.

Sublimation is defined as a process in which solid converts into gas directly without converting into liquid.

In the sublimation process, the reaction is an endothermic reaction, as the chemical bonds between molecules are broken down in order to release them into the air. Therefore ,the energy is released and so it is an endothermic reaction.

The heat or energy required to change the state from solid to gas is called the enthalpy of sublimation .Generally, it is expressed as KJ/m o l. Sublimation only occurs at pressures and temperatures .

Hence , Naphthalene is a substance that sublimes at room temperature and pressure.

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Answer:

A.Scientists use genes to explain why evolution happens.

Explanation:

:)

Answer:

Strontium, a group 2 element with an electron configuration of 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² , will form a +2 ion in a chemical bond.

Explanation:

An ionic bond is produced between metallic and non-metallic atoms, where electrons are completely transferred from one atom to another. During this process, one atom loses electrons and another one gains them, forming ions. Usually, the metal gives up its electrons forming a cation to the nonmetal element, which forms an anion.

So an ion is an atom or group of atoms that have an electric charge. A cation is an ion that has a positive charge.

The alkali metals in the earth (Elements IIA) lose two electrons to form a 2+ cation. Strontium is an alkali metal that loses the two electrons belonging to 5s², forming the +2 ion.

Answer:

+2

Explanation:

Answer:

gasoline

Explanation:

Answer:

12.78 or 12.80 mostly like 12.78

Explanation:

Answer:

please give more clarification

Answer:

first answer

Explanation:

atomic number of bromine is 35

[tex]1{s}^{2} 2 {s}^{2} 2 {p}^{6} 3 {s}^{2} 3 {p}^{6} 3 {d}^{10} 4 {s}^{2} 4 {p}^{5} [/tex]

Answer:

1s22s22p63s23p64s23d104p5

Explanation:

;)

Answer:

The angular alignment is 90 degrees

Explanation:

The neap tide is a type of tide which occurs around seven days after a spring tide. This type of tide happens twice every month.

The tide is usually moderate and it exists when the sun and moon are usually at right angles to each other when it occurs. A right angle is also known as 90 degrees which validates the tide occurring at an angle 90.

Answer:

your answer will be photosynthesis

Explanation:

Answer:

C) Liquids and gases

Explanation:

The correct answer would be liquids and gases.

The molecules of liquids and gases move randomly when held in a container. The random movement causes a collision between the molecules of the liquids/gases and between the walls of the container, creating pressure in the process. This is unlike the molecules of solids that vibrate about fixed positions.

Hence, the correct option is C.

Answer:

90.2%

Explanation:

% yield = actual yield/ theoretical yield * 100%

% yield = (312/346)*100% = 90.2%

Answer:

a

2.0 M

Explanation:

divide 6by 3

formula :  molarity=moles divided by volume of solutions

Answer:

3.34x10¹⁶ molecules of aspirin are in a drop of blood

Explanation:

The recomended dose of aspirin in blood is 100.0μg/mL =

1x10⁻⁴g aspirin / mL of blood.

In a drop (0.100mL) there are:

0.100mL ₓ (1x10⁻⁴g aspirin / mL of blood) = 1x10⁻⁵g aspirin.

Molecular mass of aspirin is:

9C = 12.01g/mol ₓ 9 = 108.09g/mol

8H = 1.01g/mol ₓ 8 = 8.08g/mol

4O = 16g/mol ₓ 4 = 64g/mol

108.09 + 8.08 + 64 = 180.17g/mol

Thus, moles of aspirin in 1x10⁻⁵g are:

1x10⁻⁵g ₓ (1mol / 180.17g) = 5.55x10⁻⁸ moles of aspirin

In 1 mole, you have 6.022x10²³ molecules, thus:

5.55x10⁻⁸ moles of aspirin ₓ (6.022x10²³ molecules / 1 mole ) =

Answer: Yes

Explanation:

Answer:

trueeeeee

Explanation:

Answer:

copper cathodes are normally referred to when talking about copper. Cathode is the purest form of copper and is the feedstock used to produce copper wire, cable, sheet, strip, tube, etc.

Explanation:

Answer: C.) Xe

Explanation: To figure out the answer go to the Noble Gas Family and count down 5 elements.

According to the electronic configuration the symbol which would be included in the noble gas notation for an element that had valence electrons in the 5 s subshell is xenon  .

Electronic configuration is defined as the distribution of electrons which are present in an atom or molecule in atomic or molecular orbitals.It describes how each electron moves independently in an orbital.

Knowledge of electronic configuration is necessary for understanding the structure of periodic table.It helps in understanding the chemical properties of elements.

Elements undergo chemical reactions in order to achieve stability. Main group elements obey the octet rule in their electronic configuration while the transition elements follow the 18 electron rule. Noble elements have valence shell complete in ground state and hence are said to be stable.

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Answer:

There are no oxygen

Explanation:

Hydro is used when naming hydrogen compound and oxo is used when naming oxygen compound

Answer:

a) [COHNH₂] = 0.001 mol/L, [NH₃] = [CO] = 0.085 mol/L

b) 5.59 atm

Explanation:

a) The decomposition reaction of formamide is the following:

COHNH₂(d)  ⇆  NH₃(g) + CO(g)    

The equilibrium constant of the reaction above is:

[tex]K_{c} = \frac{[NH_{3}][CO]}{[COHNH_{2}]} = 4.84 (400 K)[/tex]

The initial concentration of formamide is:

[tex] C_{COHNH_{2}} = \frac{\eta}{V} = \frac{0.186 moles}{2.16 L} = 0.086 mol/L [/tex]

Where: η is the number of moles and V is the volume

Now, in the equilibrium the concentration of all species is:

COHNH₂(d)  ⇆  NH₃(g) + CO(g)  

0.086 - x              x             x

[tex] K_{c} = \frac{[NH_{3}][CO]}{[COHNH_{2}]} = \frac{x*x}{0.086 - x} [/tex]  

[tex] 4.84*(0.086 - x) -x^{2} = 0 [/tex]

By solving the above equation for x we have:

x = 0.085 mol/L = [NH₃] = [CO]

[COHNH₂] = 0.086 - 0.085 = 0.001 mol/L

Therefore, the concentrations of all species present at equilibrium at 400 K is [NH₃] = [CO] = 0.085 mol/L and [COHNH₂] = 0.001 mol/L.

b) To find the total pressure in the container we need to find first the constant Kp as follows:

[tex] K_{p} = K_{c}*RT^{\Delta n} [/tex]

Where R is the gas constant = 0.082 Latm/(Kmol), T is the temperature = 400 K and Δn = 1

[tex] K_{p} = K_{c}*RT^{\Delta n} = 4.84*(0.082*400)^{1} = 158.8 [/tex]

Now, the total pressure is:

[tex] p_{T} = p_{COHNH_{2}} + p_{NH_{3}} + p_{CO} [/tex]

The pressure of COHNH₂ can be found using Ideal Gas Law:

[tex] P = \frac{nRT}{V} = \frac{0.186 moles*0.082 L*atm/(K*mol)*400 K}{2.16 L} = 2.82 atm [/tex]

Using the equilibrium constant we can find the pressure of NH₃ and CO:

COHNH₂(d)  ⇆  NH₃(g) + CO(g)  

2.82 - x              x             x

[tex] K_{p} = \frac{P_{NH_{3}}*P_{CO}}{P_{COHNH_{2}}} [/tex]

[tex] 158.8*(2.82 - x) - x^{2} = 0 [/tex]

By solving the above equation for x we have:

[tex] x = P_{NH_{3}} = P_{CO} = 2.77 atm [/tex]

[tex] P_{COHNH_{2}} = 2.82 - 2.77 = 0.05 atm [/tex]

Thus, the total pressure is:

[tex] p_{T} = p_{COHNH_{2}} + p_{NH_{3}} + p_{CO} = (0.05 + 2.77 + 2.77) atm = 5.59 atm [/tex]

Hence, the total pressure in the container at equilibrium is 5.59 atm.

I hope it helps you!

Answer:

Dmitri Mendeleev

Explanation:

He was a Russian Scientist who decided to reorganize the periodic table after other notable scientists such as Antoine-Laurent Lavoisier had also tried to organize it based on the states of matter of the elements.

Mendeleev reorganized the period in the order of increasing atomic mass although there were some other modifications by modern scientists.

Answer:

a) 64.27%

b) 58%

c) ethanol is the limiting reactant

d) ethanol is the limiting reactant

Explanation:

We have to note that the expected yield is the theoretical yield while the actual mass or amount of product formed is the actual yield.

a) theoretical yield=68.3g

Actual yield= 43.9 g

Percentage yield= 43.9/68.3 ×100

Percentage yield= 64.27%

b) theoretical yield= 0.0722 moles

Actual yield = 0.0419

Percentage yield= 0.0419/0.0722 × 100

Percentage yield= 58%

c) note that the limiting reactant yields the least number of moles of product

Ethanol will be the limiting reactant since it is not present in excess.

d) from the reaction equation;

1 mole of acetic acid produces 1 mole of ethyl acetate

0.58 moles of ethanol produces 0.58 moles of ethyl acetate

1 mole of acetic acid yields 1 mole of ethyl acetate

Hence 0.82 moles of acetic acid yields 0.82 moles of ethyl acetate

Hence ethanol is the limiting reactant.

Answer:

Zinc Carbonate

Zinc Nitrate

Explanation:

Answer:

Explanation:

1. The element you selected is Sodium. some of the physical properties are

i. Sodium has a strong metallic lustre

ii. Sodium are usually silver white in color

iii. Sodium is soft it can be cut with knife

iv. Sodium are malleable and ductile.

v.  Sodium conduct electricity

Sodium belong to group 1 elements which are called Alkali metals. Sodium have one valency electron and it gives this electron easily during bonding . This is one reason sodium and other alkali metals are very reactive. Sodium can instantly be oxidized by water.  Sodium has a relative atomic mass of approximately 23 amu.

2. There are various models that describe atoms .This models includes John Dalton models, J.J Thompson model, Ernest Rutherford model, Bohr's models etc. This models made us understand the role and location of each sub atomic particles. The models shed more light on subatomic particles like electron which revolve around the nucleus.  It provide more information on what contribute to the weight of an atom.

3. The proton , neutron and electron are subatomic particles of an atom. The proton and the neutron are located at the nucleus of an atom.  The proton and neutron contributes majorly to the weight of an atom. The proton is positively charge while neutron has no charge.

Electron is found to move around the nucleus in cloud. The electron is negatively charge. The electron determines bonding of atoms. An atom is electrically neutral if the number of proton is equal to the number of electron.

4. The four fundamental forces includes weak nuclear forces , strong nuclear forces , gravity and electromagnetic forces.

Weak nuclear forces is responsible for particle decay .Nuclear forces don't play a role in chemical reaction . If they are involve in a reaction it becomes nuclear reaction not chemical reaction.

Strong nuclear forces causes a strong nuclear interaction and it is the strongest among the 4 fundamental forces. This strong force only operate when subatomic particles are much closer to each other.

Gravity force is too weak to affect chemical reaction much. The gravity forces involves the interaction between two objects with energy and mass.

The electromagnetic force act between charged particles like negatively charged electron and positively charged proton. Electromagnetic force is the most important force in chemical bonding as it depends on the arrangement of atoms and the state of their electron. Electromagnetic forces exist in various forms like the covalent bond, metallic, ionic , dipole dipole, hydrogen bonds and many more. The major force involve in chemical bonding is the electromagnetic force.