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prisoha [69]
3 years ago
5

30 points pls i need help i need the right answer

Chemistry
2 answers:
satela [25.4K]3 years ago
8 0

Answer:

C

Explanation:

yes,

Angelina_Jolie [31]3 years ago
5 0
The answer is C I think
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Helium is the lightest noble gas and the second most abundant element (after hydrogen) in the universe. The mass of a helium−4 a
dmitriy555 [2]

<u>Answer:</u> The fraction of atom's mass contributed by nucleus is 0.99

<u>Explanation:</u>

Nucleons are defined as the sub-atomic particles which are present in the nucleus of an atom. Nucleons are protons and neutrons.

The isotopic symbol of Helium-4 atom is _2^4\textrm{He}

Number of electrons = 2

Number of protons = 2

Number of neutrons = 4 - 2 = 2

We are given:

Mass of He-4 atom = 6.64648\times 10^{-24}g

Mass of 1 electron = 9.10939\times 10^{-28}g

Calculating the mass contributed by the nucleus = m_{He}-2(m_e)

Mass of the nucleus of He-4 atom = 6.64648\times 10^{-24}-(2\times (9.10939\times 10^{-28}))=(6.64648-0.0018219)\times 10^{-24}=6.64466\times 10^{-24}

To calculate the fraction of atom's mass contributed by the nucleus, we use the equation:

\text{Fraction of atom's mass contributed by nucleus}=\frac{\text{Mass of nucleus}}{\text{Mass of atom}}

Putting values in above equation, we get:

\text{Fraction of atom's mass contributed by nucleus}=\frac{6.64466\times 10^{-24}g}{6.64648\times 10^{-24}g}=0.99

Hence, the fraction of atom's mass contributed by nucleus is 0.99

8 0
3 years ago
you record the sea temperature at 12 degrees North 45 degrees West to be 27.5 degrees Celcius the humidity to be very high and a
Cerrena [4.2K]
 For a hurricane to form, the sea temperature must be at least 26.7. The temperature of the water in the problem is 27.5. 
Another condition is that there should be little wind in the area. The problem states that there is a very light breeze. Finally, the humidity must be high.
Therefore, it is expected that a hurricane will form at the given location.
4 0
3 years ago
45 Three samples of the same solution are tested, each with a different indicator. All three indicators, bromthymol blue, bromcr
ANEK [815]

<u>Answer:</u> The correct answer is Option 4.

<u>Explanation:</u>

Bromothymol blue, Bromocresol green and Thymol blue are the indicators which change their color according to the change in pH of the solution.

The pH range and color change of these indicators are:

  1. Bromothymol Blue: The pH range for this indicator is 6.0 to 7.5 and color change is from yellow to blue. It appears yellow below pH 6.0 and blue above pH 7.5
  2. Bromocresol green: The pH range for this indicator is 3.5 to 6.0 and color change is from yellow to blue. It appears yellow below pH 3.5 and blue above pH 6.0
  3. Thymol Blue: The pH range for this indicator is 8.0 to 9.6 and color change is from yellow to blue. It appears yellow below pH 8.0 and blue above pH 9.6

As, the highest pH of all the indicators is 9.6, so every indicator will appear blue above pH 9.6.

Hence, the correct answer is Option 4.

3 0
3 years ago
Read 2 more answers
How many molecules are in 18moles of CH.​
-Dominant- [34]

Answer:

1.08 x 10²⁵molecules

Explanation:

From the mole concept we know that ;

      1 mole of any substance contains 6.02 x 10²³ molecules

This number is the Avogadro's number.

 So;

  18 mole of CH will contain:

       Number of molecules of CH  = 18 x 6.02 x 10²³ = 1.08 x 10²⁵molecules

The number of molecules is therefore 1.08 x 10²⁵molecules

8 0
2 years ago
Question 6 (4 points)
pishuonlain [190]

Answer:

20.9%

Explanation:

I took the test i hope this helps:)

8 0
3 years ago
Read 2 more answers
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