Asap worth 20 points

Naturally occurring silicon has an atomic mass of 28.086 and consists of three isotopes. The major isotope is 28Si, natural abun

Elden [556K]

Answer:

29Si has a natural abundance of 4.68%.

30Si has a relative atomic mass of 29.99288 and a natural abundance of 3.09%.

Explanation:

The atomic mass of silicon is given by:

Si=Si²⁸×A₁+Si²⁹×A₂+Si³⁰×A₃

Where:

Si: atomic mass of silicon (28.086)

Si²⁸: relative atomic mass of 28Si (27.97693)

A₁: natural abundance of 28Si (92.23%)

Si²⁹: relative atomic mass of 29Si (28.97649)

A₂: natural abundance of 29Si

Si³⁰: relative atomic mass of 30Si

A₃: natural abundance of 30Si

We also know that 30Si natural abundance is in the ratio of 0.6592 to that of 29Si.

We have to set up a system of three equations in three unknowns:

Si=Si²⁸×A₁+Si²⁹×A₂+Si³⁰×A₃

A₃=0.6592×A₂

A₁+A₂+A₃=1

First, we find substitute the value of A₃ in the third equation and solv teh value of A₂:

A₁+A₂+0.6592×A₂=1

A₁+1.6592×A₂=1

1.6592×A₂=1-A₁

A₂= $\frac{1-A₁}{1.6592}=\frac{1-0.9223}{1.6592}$ =0.0468

Then, we find the value of A₃:

A₃=0.6592×A₂

A₃=0.6592×0.0468=0.0309

Finally, we find the value of Si³⁰ in the first equation:

Si=Si²⁸×A₁+Si²⁹×A₂+Si³⁰×A₃

28.086=27.97693×0.9223+28.97649×0.0468+Si³⁰×0.0309

28.086=27.15922+Si³⁰×0.0309

28.086-27.15922=Si³⁰×0.0309

$\frac{0.92678}{0.0309}$ =Si³⁰

Si³⁰=29.99288

8 0

3 years ago

How many atoms or moles of each element are on either side of the yield arrow? Is this equation balanced? 2Na+H2O---> NaOH+2H

Anton [14]

4 NA+4H2O —> 4NaOH+2H2

I hope that helped

4 0

3 years ago

This is the chemical formula for talc (the main ingredient in talcum powder): mg3(si2o5)2(oh)2. an analytical chemist fins that

weqwewe [10]

In one mole of talc, we observe that there are:
3 moles of Mg
4 moles of Si
2 moles of H
12 moles of O

The molar ratio of O to Mg is then:

12 moles of O : 3 moles of Mg = 4 : 1

Therefore, if 6.1 moles of Mg are present, the moles of O are:

4 * 6.1 = 24.4 moles of O

7 0

3 years ago

How many spirals does a DNA molecule have?

ella [17]

Answer:

two

Explanation:

2

8 0

3 years ago

Read 2 more answers

Amantadine is effective in preventing infections caused by the influenza A virus and in treating established illnesses. It is th

Sliva [168]

Answer:

See image attached

Explanation:

a)

The full reaction mechanism of step 1 was obtained from Bartleby and attached to this answer. The steps involved in the reaction are:

1) Loss of Br- and formation of a carbocation

2) Attack of CH3CN on the carbocation

4) Formation of a quaternary nitrogen intermediate

5) Attack of water on the quaternary nitrogen intermediate

6) Loss of the water molecule

5) Formation of the amide product

b)

i) sodium hydroxide

ii) HCl

7 0

3 years ago