Here's the question ~

Heat treatment of muscular pain involves radiation of wavelength of about 900 nm (nm = 10-⁹ m). which spectral line of H - atom is suitable for this purpose ?

[ RH = 1 × 10⁵ cm-¹ ]

[ h = 6.6 × 10-³⁴ Js ]

[ c = 3 × 10⁸ m/s ]


Thanks for Answering ! ​

Answer:

D

Explanation:

Protons and Neutrons both have a mass of about 1 amu so you add them but electrons have a mass of 0 amu so they are left out.

Answer:

The conjugate base of a very weak acid is stronger than the conjugate base of a strong acid.  

Explanation:

The stronger the acid, the weaker its conjugate base and vice versa  A very weak acid has a very strong conjugate base.

Answer:

It's option a) Permeability.

Answer:

A

Explanation:

this is because combustion is the chemical reaction between surfaces including OXYGEN to generate heat and light in the form of flame

Answer:

All properties of matter are either physical or chemical properties and physical properties are either intensive or extensive. ... Physical properties can be measured without changing a substance's chemical identity. Chemical properties can be measured only by changing a substance's chemical identity.

Explanation:

Explanation:

Liquid-based lubricant

Answer:

study island : food service equipment

Explanation:

Answer:

metal : Mercury(Hg)

non metal : bromine (Br)

Explanation:

mercury is liquid at room temperature and pressure and the same as bromine

Answer:

a

Explanation:

Answer:

Im pretty sure it's B, almost 100% sure

Explanation:

Answer:

92.01 g/mol

Explanation:

So first you need to find the empirical formula by the percents. That would be, assuming that you have 100 grams of the the sample, divide each quantity of each element found by its respective molar mass.

30.4 g of N ÷ 14 g/mol N= 2.17 mol of N

69.6 g of O ÷ 16g/mol= 4.35 mol of O

You can establish now the empirical formula.

N2.17O4.35,

but since you can't have a decimal subscript, you divide each subscript by the minimum subscript

NO2

So then you're said that the molecular formula derived from that empirical formula has 2 nitrogen, so you multiply all the subscripts, by 2:

N2O4

-Dinitrogen Tetraoxide

-Nitrogen oxide (IV)

Then all you have to do is find the molecular mass of the compound using the periodic table and what you obtain is the molar mass.

remember: molecular mass is correspondent to molar mass.

Answer:

it'll halve

Explanation:

the gas is compressed with twice the pressure. The volume will be halved.

im certain

Answer: Molar masses 40.8 and 100.1

Explanation:

Answer:

A

Explanation:

Answer:

A

Explanation:

refer to textbook

Answer:

its D, convection cells

The boiling point of salt water is greater than that of fresh water hence the electrostatic forces between molecules in salt water is greater than that between the molecules in salt water.

Fresh water contains does not contain dissolved solutes like salt water. Salt water contains a lot of dissolved mineral salts making the salt water to be rich in ions.

Generally, the boiling points of substances can serve as a measure of the strength of electrostatic forces between molecules in either kind of water. We will easily find the that the boiling point of salt water is far higher than that of fresh water indicating greater electrostatic forces between molecules in salt water than between molecules in fresh water.

Learn more about boiling point: https://brainly.com/question/2153588

Both the elements combine together due to incomplete outermost shell.

Two atoms of element Q mixed with element E​ in order to achieve stability because both the elements have incomplete outermost shell which make them very reactive. In element E we can see that it has 7 electrons while on the other hand, element Q has 5 number of electrons.

For gaining stability, each element has to reach 8 electrons so that's why both the elements react with each other and get stability so we can conclude that both the elements combine together due to incomplete outermost shell.

Learn more about reaction here: https://brainly.com/question/11231920

Learn more: https://brainly.com/question/26045025

Answer:

B. atomic mass

Explanation:

He arranged the elements into rows in order of increasing mass so that elements with similar properties were in the same column.

Answer:

The strong electric force.

Explanation:

Trust me. If its wrong, comment on this, don't delete it. If someone else answers with the wrong question than other students might get the answer wrong. So if its right, say that it is, if its wrong, tell others what the real answer is.

Answer: 23.53g

Explanation:

5.2/(2x16) = 0.1625 mol

0.1625 x 2 = 0.325 mol

0.325 x (23 x 2 + 16 x 2) = 78 x 0.325 = 23.53g

Answer:

b)

Explanation:

It shows the natrual proggresion of a story and helps blend the narrtive together.

Answer:B

Explanation: i took the quiz on edge

Finding molar mass of NaOH

We know that

Molar mass of Sodium (Na) = 23 g/mol

Molar mass of Oxygen (O) = 32 g/mol

Molar mass of Hydrogen (H) = 2 g/mol

So,

Mass of 1 mole of NaOH

=> 1 × 23 + 1 × 16 + 1 × 1

=> 23 + 16 + 1

=> 40 g/mol

Now,

Mass = 40 × 0.25

Mass = 10 g

Taking into account the degrees Celsius and Kelvin, if the temperature changes by 100 K, by 100 degrees Celsius it change in degrees Celsius.

A degree Centigrade is a unit of temperature (the physical quantity that reveals the level of heat) whose symbol is °C.

On the other hand, the degree Kelvin, whose symbol is K, is the unit of temperature on the scale created by William Thomson Kelvin, in 1848, based on the degree Celsius, he established his zero point (0) at zero absolute (-273.15 ° C). The figure 0 K is equivalent to the theoretical point where gases have no volume. Absolute zero or 0 K is the point where molecules theoretically stop moving. It is the "perfect" cold.

Considering that zero on the Celsius or degrees centigrade (0 ° C) scale is defined as the equivalent of 273.15 K, the conversion from degrees ° C to K is carried out using the following expression:

T(K)= T(°C) + 273.15 K

In this case, if the temperature changes by 100 K, as it is a change in temperature, the numerical value in K units is the same in ° C units.

Then, the correct answer is option B. if the temperature changes by 100 K, by 100 degrees Celsius it change in degrees Celsius.

Learn more about degrees Celsius and Kelvin:

Answer:

2) To find the atoms from the moles, you just multiply Avogadro's number (6.02 x 10^23) by the moles.

So 3.35 x (6.02 x 10^23) = 2.0167 x 10^24 atoms are in 3.35 moles of aluminum

3) If the question is asking under standard temperature and pressure, we know that if we divide the volume by the molar volume of a gas (which is 22.7 in standard temperature and pressure), we can get the moles.  

So 101.25L / 22.7 = 4.46 mol

4) We know that to find the moles, it is the mass divided by the molar mass. If we rearrange the equation to solve for mass, we have to multiply the moles by the molar mass to get there.

Nitrogen's (N) molar mass on the periodic table is 14g/mol, but since Nitrogen is a diatomic element, it would be N2 by itself. So multiply 14 by 2, which will give you 28g/mol. N2's molar mass is 28g/mol.

Now you multiply 13.7 moles by 28g/mol, which will give you 383.6g

Just did a few edits here, 4.46 for question 3 is in moles not L

Taking into account the definition of avogadro's number,

2. 3.35 moles of aluminum contains 2.018ײ⁴ atoms.

3. 4.52 moles of CO₂ gas are in a 101.25 L container filled with CO₂ gas.

4. 13.7 moles of N₂ contain 383.6 grams.  

Avogadro's Number is called the number of particles that make up a substance (usually atoms or molecules) and that can be found in the amount of one mole of said substance. Its value is 6.023×10²³ particles per mole. Avogadro's number applies to any substance.

Then you can apply the following rule of three: if 1 mole of aluminum contains 6.023×10²³ atoms, then 3.35 moles of aluminum contains how many atoms?

amount of atoms of aluminum= (6.023×10²³ atoms × 3.35 moles)÷ 1 mole

amount of atoms of aluminum=2.018ײ⁴ atoms

Finally, 3.35 moles of aluminum contains 2.018ײ⁴ atoms.

The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.

Then, you can apply the following rule of three: If by definition of the STP conditions 1 mole of CO₂ occupies a volume of 22.4 L, how many moles does 101.25 L occupy?

[tex]amount of moles of CO_{2} =\frac{101.25 Lx1 mole of CO_{2} }{22.4 L}[/tex]

amount of moles of CO₂= 4.52 moles

4.52 moles of CO₂ gas are in a 101.25 L container filled with CO₂ gas.

The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

In this case, the molar mass of N₂ is 28 g/mole. So, you can apply the following rule of three:  If 1 mole of N₂ contains 28 grams, 13.7 moles of N₂ contain how much mass?

[tex]mass=\frac{13.7 moles x28 grams}{1 mole}[/tex]

mass= 383.6 grams

13.7 moles of N₂ contain 383.6 grams.

Learn more about

Answer:

Most of the elements in the periodic table are metals.

Hope that helps. x

Answer:

Here is your answer,mate!

Explanation:

Metals are the most of the elements in the periodic table.

Gravitational Potential energy:

The Gravitational potential energy of

an object at a point above the ground

is defined as the work done in raising

it from the ground to that point against

gravity.

Consider an object of mass "m" is raised

to heighth from the ground.

A force is required to do this. the

minimum force required to raise the

object is equal to the weight of the

object[mg]

The object gains energy equal to the

work done on it. Let the work done on

the object against gravity be "w"

WorkDone=W= Force x displacement

=mgxh

..W=mgh

since the workdone on the object is

equal to "mgh" an energy equal to "mgh"

units is gained by object.This is the

potential energy of object at height "h"

.. P.E=mgh

Answer:

If you are given with the atomic number of an element you can find it's period number and group number. The period number is related to the number of electron occupied shells in the element and the period number is linked to its valence electrons.

Explanation:

hope it helps luv <3