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stich3 [128]
3 years ago
9

Boron has two isotopes, Boron 10 which has a mass of 10.0129 amu and Boron-11 with a mass of 11.0093 amu. B-10 occurs 84.74% of

the time and 11 occurs 15.26% of the time. What is the average atomic mass of boron?
Chemistry
1 answer:
podryga [215]3 years ago
3 0

The average atomic mass of Boron: 10.431 amu

<h3>Further explanation   </h3>

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.  

So Isotopes are elements that have the same Atomic Number (Proton)  

Atomic mass is the average atomic mass of all its isotopes  

In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu  

Mass atom X = mass isotope 1 . % + mass isotope 2.%  + ...

The average atomic mass of boron :

\tt avg~mass=0.8474\times 10.0129+0.1526\times 11.0093\\\\avg~mass=10.431~amu

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Mg2OH has how many unique elements?<br> A. <br> 4<br> B. <br> 2<br> C. <br> 3<br> D. <br> 5
frutty [35]

Answer:

Magnesium hydroxide has 3 unique elements.

Explanation:

Long story short, 2 is the balancing compound in structure to make up hydroxide, therefore 1 compound would be left to create Mg(2O)H.

(This is only an opinion of mathematical science to me, I don't have complete understanding of this subject either, good luck.)

5 0
3 years ago
A 5.00-mL sample of blood was treated with trichloroacetic acid to precipitate proteins. After centrifugation, the resulting sol
Anarel [89]

Explanation:

According to the Beer-lambert' s law,

        Absrobance = absrobptitvity × lenght × concentration

So, if we will plot a graph between absrobance and concentration then we will obtain a straight line

Hence, formula to calculate slope of the graph is as follows.

   The slope of graph = \frac{\text{difference in absrobance at two points}}{\text{difference in concentrations at those points}}

The given data is as follows.

     A_{1} = 0.412 (first point)

     A_{2} = 0.642 (second point)

     C_{1} = 0.240 ppm (first point)

     C_{2} = 0.475 ppm (second point)

Hence, putting these values into the above formula we will calculate the value of slope as follows.

           Slope = \frac{\text{difference in absrobance at two points}}{\text{difference in concentrations at those points}}

                     = \frac{0.642 - 0.412}{0.475 - 0.240}

                      = \frac{0.23}{0.235}

                     = 0.978

It is known that for the graph, line equation can be written as follows.

                       y = mx + c  ........... (1)

where,      C = intercept

                 m = slope

Hence, calculate the value of intercept as follows.

           0.412 = 0.24 \times 0.978 + c

               c = 0.178

As it is given that the absorbance values 0.454 (the y-axis value). Therefore, putting this value into equation (1) we get the following.

                     y = mx + c

                  0.454 = x \times 0.978 + 0.178

                   0.276 = 0.978x

                         x = 0.282 ppm

Thus, we can conclude that the concentration of Pb in the given sample is 0.282 ppm.

3 0
3 years ago
Validate how valence electrons determine the chemical reactivity of an element: give 2 examples of elements with high reactivity
Ostrovityanka [42]
Nitrogen is more reactive than oxygen and oxygen than chlorine
8 0
3 years ago
Which of the following intermolecular forces would affect boiling point the most?
Alekssandra [29.7K]
Hydrogen Bonding will effect the boiling point the most. Let's take an example Butane a four carbon unsaturated organic compound with molecular formula C₄H₁₀ and boiling point -1 °C.

                                                H₃C-CH₂-CH₂-CH₃

Now, replace one hydrogen on terminal carbon with -OH group and convert it into Butanol.

                                                H₃C-CH₂-CH₂-CH₂-OH

The Boiling point of Butanol is 117.7 °C. This increase in boiling point is due to formation of hydrogen bondings between the molecules of Butanol. 
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2 years ago
If a substance melts at 20oC, what is its freezing point?
shutvik [7]

Answer:

It is difficult, if not impossible, to heat a solid above its melting point because the heat that ... in a solid are packed in a regular structure that is characteristic of that particular substance.

<h3>#carryONlearning </h3>

4 0
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