Density Calculations

The atomic mass is the sum of the number of ________ and ________ in the nucleus of an atom. Choose two answers from the options

iVinArrow [24]

Answer :

The atomic mass is the sum of the number of protons and neutrons in the nucleus of an atom.

Explanation :

Atomic number : it is defined as the number of protons or number of electrons.

Atomic number = number of protons = number of electrons

Mass number or atomic mass : It is defined as the sum of the number of protons and the number of neutrons.

Mass number or atomic mass = Number of protons + Number of neutrons

For example :

Number of protons in carbon = 6

Number of neutrons in carbon = 6

Mass number or atomic mass = Number of protons + Number of neutrons

Mass number or atomic mass = 6 + 6

Mass number or atomic mass = 12

Thus, the atomic mass is the sum of the number of protons and neutrons in the nucleus of an atom.

3 0

3 years ago

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What do acids and bases have in common apex?

disa [49]

Both acids and bases produce a part of a water molecule. Bases dissociate hydroxide (–OH) ions and acids, hydrogen (H+) ions that when combined form water. Both are also very corrosive when they are strong enough that they fully dissociate in water.

8 0

3 years ago

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Choose all the answers that apply.

Arada [10]

Answer:

removing topsoil

Explanation:

5 0

3 years ago

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Nitrogen effuses through a pinhole 1.7 times as fast as another gaseous element under the same conditions. Estimate the other el

marysya [2.9K]

Answer:

80.92, Krypton

Explanation:

What is effusion?

• It is a process where gas escapes through a pinhole (a very small hole) into a region of low pressure or vacuum

Graham's law of effusion of gas

• states that at a given constant temperature and pressure, the rate of effusion of gases is inversely proportional to the square root of their molar masses

$\boxed{ \frac{Rate_1}{Rate_2} = \sqrt{ \frac{M_2}{M_1} } }$

Calculations

Nitrogen exist as N₂ at room temperature, thus its molar mass is 2(14)= 28.

Let the rate and molar mass of unknown gas be Rate₂ and M₂ respectively.

Since N₂ effuses 1.7 times as fast as the unknown gas,

Rate₁= 1.7(Rate₂)

$\frac{Rate_1}{Rate_2} = 1.7$

$1. 7 = \sqrt{ \frac{M_2}{28} }$

Square both sides:

$2.89 = \frac{M_2}{28}$

Multiply both sides by 28:

2.89(28)= M₂

M₂= 80.92

Identity of gas

The molar mass of 80.92 lies between Bromine and Krypton. However since Bromine exist as Br₂, the value of it's molar mass would be 159.8 instead. Hence, Bromine is eliminated.

If the gas is a diatomic element, the atomic weight is 80.92 ÷2= 40.46. Thus, we are now considering if Argon could be its identity. However, Argon is a noble gas and will not exist as a diatomic element. Argon is therefore eliminated too.

Thus based on the above reasoning, its probable identity is Krypton.

7 0

3 years ago

Scientists have been able to find a full record of Earth's fossil history, thus making the fossil record complete.

Arada [10]

Answer:

False

Explanation:

Few organisms were not preserved as well as others, and new fossils are found every day

5 0

3 years ago