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3 years ago

Oxygen has an atomic mass of 16 and an atomic number of 8. how many neutrons are present

1 answer:

Alex3 years ago

7 0

An atoms atomic mass is the sum of it's proton and neutrons found in the nucleus. An atom's atomic number is the number of protons an atom has. By subtracting an element's atomic number from the atomic mass you can calculate the number of neutrons. For oxygen it would be sixteen minus eight, so oxygen has eight neutrons.

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The average atomic mass of Eu is 151.96 amu. There are only two naturally occurring isotopes of europium, Eu with a mass of 151.

earnstyle [38]

Answer:

The percentage abundance of Eu isotopes are 52 % and 48 % .

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})$

Given that:

Since the element has only 2 isotopes, so the let the percentage of first be x and the second is 100 -x.

For first isotope,:

% = x %

Mass = 151.0 amu

For second isotope :

% = 100 - x

Mass = 153.0 amu

Given, Average Mass = 151.96 amu

Thus,

$151.96=\frac{x}{100}\times {151.0}+\frac{100-x}{100}\times {153.0}$

Solving for x, we get that:

x = 52 %

Thus percentage abundance of Eu isotopes are 52 % and 48 % .

7 0

3 years ago

A chemical reaction is shown below:

BabaBlast [244]

Answer:

Mass = 8.46 g

Explanation:

Given data:

Mass of water produced = ?

Mass of glucose = 20 g

Mass of oxygen = 15 g

Solution:

Chemical equation:

C₆H₁₂O₆ + 6O₂ → 6H₂O + 6CO₂

Number of moles of glucose:

Number of moles = mass/molar mass

Number of moles = 20 g/ 180.16 g/mol

Number of moles = 0.11 mol

Number of moles of oxygen:

Number of moles = mass/molar mass

Number of moles = 15 g/ 32 g/mol

Number of moles = 0.47 mol

now we will compare the moles of water with oxygen and glucose.

C₆H₁₂O₆ : H₂O

1 : 6

0.11 : 6/1×0.11 = 0.66

O₂ : H₂O

6 : 6

0.47 : 0.47

Less number of moles of water are produced by oxygen thus it will limit the yield of water and act as limiting reactant.

Mass of water produced:

Mass = number of moles × molar mass

Mass = 0.47 mol ×18 g/mol

Mass = 8.46 g

8 0

3 years ago

The formation of a gas in a chemical reaction, due to ions changing places, often indicates that the reaction is which type?

Gelneren [198K]

A single-displacement reaction, also known as asingle-replacement reaction, is a type of chemicalreaction where an element reacts with a compound and takes the place of another element in that compound. This type of reaction is typically pictured like this: Here, A replaces B in the compound BC.

6 0

3 years ago

Read 2 more answers

Why did the outside of the bag get wet? From ice melting in the bag

dezoksy [38]

Because the water seeped through the bag (? I don’t know the context correct me if I’m wrong)

7 0

2 years ago

How would a collapsing universe affect light emitted from clusters and superclusters? A. Light would acquire a blueshift. B. Lig

Lady_Fox [76]

Answer:

Choice A: Light would acquire a blueshift.

Explanation:

When a universe collapses, clusters of stars start to move towards each other. There are two ways to explain why light from these stars will acquire a blueshift.

Stars move toward each other; Frequency increases due to Doppler's Effect.

The time period $t$ of a beam of light is the same as the time between two consecutive peaks. If $\lambda$ is the wavelength of the beam, and both the source and observer are static, the time period $T$ will be the same as the time it takes for light travel the distance of one $\lambda$ (at the speed of light in vacuum, $c$ ).

$\displaystyle t = \frac{\lambda}{c}$ .

Frequency $f$ is the reciprocal of time period. Therefore

$\displaystyle f = \frac{1}{t} = \frac{c}{\lambda}$ .

Light travels in vacuum at a constant speed. However, in a collapsing universe, the star that emit the light keeps moving towards the observer. Let the distance between the star and the observer be $d$ when the star sent the first peak.

Distance from the star when the first peak is sent: $d$ .
Time taken for the first peak to arrive: $\displaystyle t_1 =\frac{d}{c}$ .

The star will emit its second peak after a time of. Meanwhile, the distance between the star and the observer keeps decreasing. Let $v$ be the speed at which the star approaches the observer. The star will travel a distance of $v\cdot t$ before sending the second peak.

Distance from the star when the second peak is sent: $d - v\cdot t$ .
Time taken for the second peak to arrive: $\displaystyle t_2 =t + \frac{d - v\cdot t}{c}$ .

The period of the light is $t$ when emitted from the star. However, the period will appear to be shorter than $t$ for the observer. The time period will appear to be:

$\begin{aligned}\displaystyle t' &= t_2 - t_1\\ &= t + \frac{d - v\cdot t}{c} - \frac{d}{c}\\&= t + (\frac{d}{c} - \frac{v\cdot t}{c}) -\frac{d}{c}\\&= t - \frac{v\cdot t}{c} \end{aligned}$ .

The apparent time period $t'$ is smaller than the initial time period, $t$ . Again, the frequency of a beam of light is inversely proportional to its period. A smaller time period means a higher frequency. Colors at the high-frequency end of the visible spectrum are blue and violet. The color of the beam of light will shift towards the blue end of the spectrum when observed than when emitted. In other words, a collapsing universe will cause a blueshift on light from distant stars.

The Space Fabric Shrinks; Wavelength decreases as the space is compressed.

When the universe collapses, one possibility is that clusters of stars move towards each other. Alternatively, the space fabric might shrink, which will also bring the clusters toward each other.

It takes time for light from a distant cluster to reach an observer on the ground. The space fabric keeps shrinking while the beam of light makes its way through the space. The wavelength of the beam will shrink at the same rate. The wavelength of the beam of light will be shorter by the time the beam arrives at its destination.

Colors at the short-wavelength end of the visible spectrum are blue and violet. Again, the color of the light will shift towards the blue end of the spectrum. The conclusion will be the same: a collapsing universe will cause a blueshift on light from distant stars.

8 0

3 years ago