Solve the following problems III — task. Science State Board, Class 10.

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1. Calculate the % relative abundance of \(B-10\) and \(B-11\), if its average atomic mass is \(10.804\) \(amu\).

Answer:

Let the % of the isotope \(B-10=x\)

Then, the % of the isotope \(B-11=100-x\)

\begin{array}{l} Average atomic mass = \frac{10 \times x + 11 (100 - x)}{100} \\ 10.804 = \frac{A}{100} \\ 10.804 = \frac{B}{100} \\ x = ? \end{array}

Where,

A \(=\)

B \(=\)

x \(=\)

% abundance of \(B-10=\)

% abundance of \(B-11=\)

2. Calculate the percentage of oxygen in \(Al_2(SO_4)_3\) (atomic mass: \(Al=27\), \(O=16\), \(S=32\)).

Answer:

Given data:

Atomic masses:

\(Al=27\), \(O=16\), \(S=32\)

Formula:

The formula to find the percentage of an element is

\(\frac{\text{X}}{\text{Y}}\times100\)

Where,

X \(=\)

Y \(=\)

Solution:

Molecular mass of \(Al_2(SO_4)_3\) \(=\)

% of \(O\) in \(Al_2(SO_4)_3\) \(=\)

Did you find an error?

17. Solve the following problems III