How many neutrons are there in 8 molecules of
[tex] \frac{19}{9} f2[/tex]
​

Answer:

All substances can be characterized by their unique sets of physical and chemical properties.

Answer: .B. 13C NMR spectra display peaks for only carbons that bear hydrogen atoms.

Explanation:

The statements that are true about 13C NMR are:

A. In 13C proton-decoupled NMR spectra, all peaks are singlets.

C 13C NMR chemical shifts occur over a greater range than 1H NMR chemical shifts.

D. 13C NMR easily differentiates between the different hybridized carbons (sp3, sp2, and sp hybridized carbons).organic-chemistry

Therefore, the option that isn't true is option B. "13C NMR spectra display peaks for only carbons that bear hydrogen atoms". This is false because 13C NMR will show every peak in the spectrum and it doesn't matter if it's only carbons that bear hydrogen atoms as everything will be shown.

Answer:

it is a mixture

element are pure and compound are formed in a fixed ratio

Explanation:

Answer:

The principal energy level remains the same

Explanation:

A principal energy level is one defines where electrons reside in an atom and that can contain one or more sub levels and have 2·n² number of electrons located in different sub levels within the energy level. Therefore, when moving up from s to p within the same principal energy level, the principal energy level does not change value.

Answer:

Explanation:

Biological.

I hope I helped you! :)

Answer:

Explanation:

1 ) Let the lattice energy per mole be x

2 K + Cl₂ =  2KCl

Applying Born- Haber cycle

2 x 89 + 2 x 419 + 243 - 2 x 349  + Δx = - 2 x 436.5

178 + 838+ 243 - 698 + Δx = - 873

Δx = 1434 kJ

Lattice energy per mole = 1434 / 2 = 717 kJ / mol

2 )

2Ca + O₂ = 2 CaO

Heat of formation of CaO = - 635 kJ

Let lattice energy be x / mol

Bond energy of oxygen = 498 kJ / mol

178 x 2 + 2 ( 590 + 1145 ) + 498 + 2 ( 744 - 141 ) + x = - 2 x 635

356 + 3470 + 1206 + 498 + 2 x = - 1270

5530 + 2 x = - 1270

x = - 3400  kJ

The lattice energy for each specie can be calculated form the Born - Haber cycle and Hess law.

a) Given that;

Heat of formation (ΔH∘f) = -436.5 kJ/mol

Ionization energy (IE) = 419 kJ/mol

Heat of sublimation(ΔHsub) = 89.0 kJ/mol

Bond energy (BE) = 243 kJ/mol

Electron affinity (EA) =  -349 kJ/mol

Lattice energy (U) = ?

From Hess law;

ΔH∘f = ΔHsub + BE + IE + EA + U

U = ΔH∘f - [ΔHsub + BE + IE + EA]

U = ( -436.5 kJ/mol) -  [89.0 kJ/mol + 243 kJ/mol +  419 kJ/mol + ( -349 kJ/mol)]

U = -838.5  kJ/mol

b)

Heat of formation (ΔH∘f) =-635 kJ/mol

Ionization energy (IE) =IE1 + IE2 = 1735  kJ/mol

Heat of sublimation(ΔHsub) = 178kJ/mol

Bond energy (BE) = 498 kJ/mol

Electron affinity (EA) =  EA1 + EA2 = 603 kJ/mol

Lattice energy (U) = ?

From Hess law;

ΔH∘f = ΔHsub + BE + IE + EA + U

U = ΔH∘f - [ΔHsub + BE + IE + EA]

U = (-635 kJ/mol) - [ 178kJ/mol + 498 kJ/mol + 1735  kJ/mol + 603 kJ/mol]

U = -3649 kJ/mol

Learn more: https://brainly.com/question/2510654

Answer:

boron has an atomic mass of 10.810 amu consists of two isotopes.

Answer:

boron has an atomic mass of 10.810 amu consists of two isotopes.

Explanation:

Answer:

False

Explanation:

Science is not based on primarily on peoples opinions and views of the subject matter whereas science is based on empirical observations and research for its validity.

Science aims to find answers to human questions related to the natural world through their research observation and experiments. Scientists and researchers provide valid proof of human questions so that people can trust them.

Science can change people's opinions regarding the natural world with valid proof and observational theories but science is not based on people's opinion.

Hence, the given statement is "false".

Answer:

[tex]m=840.88g[/tex]

Explanation:

Hello,

In this case, considering the ideal gas equation as:

[tex]PV=nRT[/tex]

We can first compute the moles of air at the given conditions of 195 kPa (1.92 atm), 10 °C (283K) and 350 L:

[tex]n=\frac{PV}{RT}=\frac{1.92atm*350L}{0.082\frac{atm*L}{mol*K}*283K}\\ \\n=29.03molAir[/tex]

Next, since the molar mass of air is 28.97 g/mol, the mass is computed to be:

[tex]m=29.03mol*\frac{28.97g}{1mol} \\\\m=840.88g[/tex]

Best regards.

mendeleev arranged the elements in order of increasing relative atomic mass. When he did this he noted that the chemical properties of the elements and their compounds showed a periodic trend

Answer:

Left to right

Elements are arranged by increasing atomic mass

Answer:brainly

Explanation:

absolutely brainly

full of help and knowledge

Answer:

C,  hydrogen.

Explanation:

Answer:

experiment showed that the atom is mostly empty space with a tiny, dense, positively-charged nucleus.

Explanation:srry im late but i dont be on it like that  hoped it helped tho srry

Answer:

Due to different atoms and different values of electronegativities.

Explanation:

NH3 and SO3 have different bond angles because both molecules have different type of atoms combine together. In NH3, nitrogen react with hydrogen while in SO3, sulfur react with oxygen atom. The bond angle of NH3 is 107 while the bond angle of SO3 is 120. This difference in bond angle is also due to different electronegativities of the bonded atoms. The electronegativity of oxygen is higher than hydrogen so repulsion of hydrogen is less and that's why its bond angle is also lower than oxygen.

Answer:

Explanation:

Polyatomic ions are ions (usually anions) that are made up of more than one atom. In order to determine the charge of anions, one can first identify the charge of the metal (which forms the cation) in a compound (which is usually easy to know) before predicting the charge of the anion. The charges are usually exchanged to form denominator of the other reacting atom/molecule, but if divisible, they are divided first before the exchange.

(a) The polyatomic ion in KNO₂ is NO₂ with the ionic equation below showing it's charge

KNO₂  ⇒ K⁺ + NO₂⁻

From the above, we can deduce that the charge of NO₂ is "1-"

(b) The polyatomic ion in CaSO₄ is SO₄ with the ionic equation below showing it's charge

CaSO₄ ⇒ Ca²⁺ + SO₄²⁻

The charge of SO₄ from the above equation is "2-"

(c) The polyatomic ion in Mg(NO₃)₂ is NO₃ with the ionic equation below showing it's charge

Mg(NO₃)₂   ⇒ Mg²⁺  +  NO₃⁻

From the above equation, it can be deduced that the charge of NO₃ is "1-"

Answer:

5.6 × 10-5 m^3

Explanation:

Hope this helps

Answer:

SO3

It has the highest molar mass value and thus would be the least soluble

Explanation:

In this question, we want to know which of the gases is the least soluble in water.

The easiest way to do this is to calculate the molar masses of these gases. The gas with the highest molar mass is the heaviest and thus will be the least soluble in water

For CO2 - molar mass is 44 g/mol

For SO3- molar mass is 80 g/mol

For N2- molar mass is 28g/mol

For NH3-molar mass is 17g/mol

For HCl- molar mass is 36.5 g/mol

From the molar masses, we can see that the molar mass of the ammonia gas is the lightest and thus, it is the most soluble.

The mass of the sulphur vi oxide is the highest and thus it is the heaviest and the least soluble in water

How does the arrangement of atoms differ in a crystalline and a noncrystalline substance? Crystals have well organized arrangement of atoms. Non crystals have irregular unorganized arrangement of atoms. You just studied 13 terms!

Answer:

16

Explanation:

B and C are ur answers

Answer:

the number of electrons is 13 and neutrons is 14

Answer: FALSE

Explanation: Magnesium is more reactive.

Hope this helps!

Answer:

False

Explanation:

Magnesium is more reactive.

Answer:

an object that conveys meaning

Explanation:

Answer:

c

Explanation:

Answer:

A ; 20g of water has the least number of molecules

Explanation:

Here, we want to know which of the options represent the least number of molecules;

To calculate this, we are going to first calculate the number of moles using the formula below;

Number of moles = mass/molar mass

Then from the number of moles, we can calculate the number of molecules by multiplying the number of moles by 6.02 * 10^23 molecules

Let’s proceed;

a. That will be 20/18.02 = 1.1099 moles

1.1099 * 6.02 * 10^23 = 6.68 * 10^23 molecules

b. That will be 77/16.06 = 4.8 moles

4.8 * 6.02 * 10^23 = 2.89 * 10*24 molecules

c. That will be 68/42.09 = 1.62 moles

1.62 * 6.02 * 10^23 = 9.73 * 10^23 molecules

d. That will be 100/44.02 = 2.27 moles

2.27 * 6.02 * 10^23 = 1.37 * 10^24 molecules

e. That will be = 84/20.01 = 4.2 moles

4.2 * 6.02 * 10^23 = 2.53 * 10^24 molecules

From all the values obtained, the lowest is 20g of water

Answer:

Number of Significant figures is : 4

Scientific Notation is: 6.3 x 10^-2

EXTRA HELP

Answer:

Distance = 1500miles

time taken = 3 hours

speed of plane = distance/time taken = 1500/3= 500milesperhour

Explanation:

According to the distance formula , the speed of the plane is 500 miles per hour.

The speed of an object is the magnitude of the change of its position over time or the magnitude of the change of its position per unit interval of time indicating that it is thus a scalar quantity.The average speed of an object in an interval of time is the distance traveled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero. Speed is not the same as velocity.

Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second (m/s), but the most common unit of speed in everyday usage is the kilometre per hour (km/h) or in the US and the UK, miles per hour (mph).

Here, speed is calculated as distance /time= 1500/3= 500 miles per hour.

Thus, the speed of plane is 500 miles per hour.

Learn more about speed,here:

https://brainly.com/question/7359669

#SPJ2