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4 years ago

What is the mass number of an atom which contains 21 electrons, 21 protons, and 24 neutrons?

Chemistry

1 answer:

murzikaleks [220]4 years ago

7 0

45 is the atomic mass of the atom. And the name is Scandium

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What do the suffix in a polyatomic ion mean

zysi [14]

Answer: The suffixes of the names of polyatomic ions have a pattern associated with them. ... For example, the sulfite ion has three oxygen atoms whereas the sulfate ion has four oxygen atoms.

5 0

3 years ago

How many grams are in 1.946 moles of nacl

Ilia_Sergeevich [38]

Answer:

113.8g

Explanation:

Statement of problem: mass of 1.946mole of NaCl

Given parameters:

Number of moles of NaCl = 1.946mole

Unknown: mass of NaCl

Solution

To find the mass of NaCl, we apply the concept of moles which expresses the relationship between number of moles and mass according to the equation below:

Number of moles = $\frac{mass}{molar mass}$

To find the molar mass of NaCl:

the atomic mass of Na = 23g

atomic mass of Cl = 35.5g

Molar mass of NaCl = (23 + 35.5) = 58.5gmol⁻¹

Mass of NaCl = Number of moles x molar mass of NaCl

Mass of NaCl = 1.946 x 58.5 = 113.8g

7 0

3 years ago

What is the longest wavelength in the Balmer series? (Hint: the Rydberg constant for Hydrogen is 1.096776×107 1/m, and the Balme

boyakko [2]

<u>Answer:</u> The longest wavelength of light is 656.5 nm

<u>Explanation:</u>

For the longest wavelength, the transition should be from n to n+1, where: n = lower energy level

To calculate the wavelength of light, we use Rydberg's Equation:

$\frac{1}{\lambda}=R_H\left(\frac{1}{n_i^2}-\frac{1}{n_f^2} \right )$

Where,

$\lambda$ = Wavelength of radiation

$R_H$ = Rydberg's Constant = $1.096776\times 10^7m^{-1}$

$n_f$ = Higher energy level = $n_i+1=(2+1)=3$

$n_i$ = Lower energy level = 2 (Balmer series)

Putting the values in above equation, we get:

$\frac{1}{\lambda }=1.096776\times 10^7m^{-1}\left(\frac{1}{2^2}-\frac{1}{3^2} \right )\\\\\lambda =\frac{1}{1.5233\times 10^6m^{-1}}=6.565\times 10^{-7}m$

Converting this into nanometers, we use the conversion factor:

$1m=10^9nm$

So, $6.565\times 10^{-7}m\times (\frac{10^9nm}{1m})=656.5nm$

Hence, the longest wavelength of light is 656.5 nm

4 0

3 years ago

What is the air speed of a unladen swallow?

Firdavs [7]

Answer: An african or a european swallow?

3 0

3 years ago

Will give brainliest, points, and more!!

tino4ka555 [31]

Do you relizes how many activities lead to global warming? When gas is burned in a car, it produces carbon dioxide (a green house gas). The carbon dioxide then floats up towards the atmosphere and becomes part of the atmosphere. This then causes the heat from the sun to get trapped, bouncing from the atmosphere to the earth. The sun will never stop producing heat which will only lead to the world getting hotter as each decade goes by.

Hope this helps you!

4 0

3 years ago

Read 2 more answers