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3 years ago

How are element identified in terms of their atoms

1 answer:

5 0

The mass number is the sum of the numbers of neutrons and protons in the nucleus. The elements can be identified unambiguously by the "spectral fingerprints" of theirline spectra and in some cases by the flame colors given off by excited atoms.

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Help me plsss

Yuki888 [10]

Answer:

8.34

Explanation:

1) how much moles of NH₃ are in the reaction;

2) how much moles of H₂ are in the reaction;

3) the required mass of the H₂.

all the details are in the attachment; the answer is marked with red colour.

Note1: M(NH₃) - molar mass of the NH₃, constant; M(H₂) - the molar mass of the H₂, constant; ν(NH₃) - quantity of NH₃; ν(H₂) - quantity of H₂.

Note2: the suggested solution is not the shortest one.

8 0

2 years ago

The half life of a radioactive element is 2 million years. a mass of rock originally contained 200g of this element. how many gr

julia-pushkina [17]

Every 2 million years the amount is halved
0 million = 200g
2 million = 200g/2 = 100g
4 million = 100g/2 = 50g

8 0

3 years ago

Substance P is carbon.

stepan [7]

Explanation:

substance Q could be oxygen (O2)

substance R could be carbon dioxide (CO2)

4 0

3 years ago

These are 3 questions in one but i really need help i put the most points i could give and i’ll give Brainliest !!

kap26 [50]

Answer:

1) 950 mL

2) 625 mmHg

3) 426 mL

Explanation:

1) This is the relationship between pressure and volume. This relationship looks like this:

P1*V1 = P2*V2

This means the first pressure times the initial volume is equal to the second pressure times the second volume. We are solving for the second volume. First, convert the mmHg to atm and the mL to L.

1 L * 1 atm = 1.053 atm * X

X = 0.95 L or 950 mL

2) This is the same concept as the last one. :) We don't have to convert the mmHg to atm since the answer wants it in mmHg.

750 mmHg * 0.25 L = 0.3 L * X

X = 625 mmHg

3) The relationship between volume and temperature is similar to the one between pressure and temperature (like the problem in your last question). Remember to convert degrees C to Kelvin and mL to L.

V1 / T1 = V2 / T2

0.4 L / 303 K = X / 323 K

X = 0.426 L pr 426 mL

These problems become much easier once you learn the relationships between the different variables (temp, pressure, volume, etc.) When you have a problem like this, I like to first determine what relationship I am dealing with and then write out what I have and what I am solving for. This helps with organizing the problem. Then just solve it like a normal algebra problem. Always remember to convert temp to Kelvin, mL to L, and pressure to atm (unless it wants it in a different unit, then just make sure all the units match).

Good luck with you studies! :)

4 0

3 years ago

In an ion with an unknown charge, the total mass of all the electrons was determined to be 2.19 ✕ 10−26 g, while the total mass

Ilya [14]

Answer:

$\large \boxed{\text{Fe$^{{2+}}$}}$