Answer:
The percent isotopic abundance of Cu-65 is 30.79 %.
The percent isotopic abundance of Cu-63 is 69.21 %.
Explanation:
we know there are two naturally occurring isotopes of carbon, Cu-63 (62.9298 amu) and Cu-65 (64.9278 amu)
First of all we will set the fraction for both isotopes
X for the isotopes having mass 62.9298 amu
1-x for isotopes having mass 64.9278 amu
The average atomic mass of copper is 63.546 amu.
we will use the following equation,
62.9298 x + 64.9278 (1-x) = 63.546
62.9298x + 64.9278 - 64.9278x = 63.546
62.9298x - 64.9278x = 63.546 - 64.9278
-1.998 x = -1.3828
x=-1.3828 / -1.998
x= 0.6921
0.6921 × 100 = 69.21 %
69.21 % is abundance of Cu-63 because we solve the fraction x.
now we will calculate the abundance of Cu-65.
(1-x)
1-0.6921 = 0.3079
0.3079 × 100 = 30.79 %
30.79 % for Cu-65.
Answer:

Explanation:

The incomplete combustion of alkanes, and other fuels actually, happens when there is a limited supply of oxygen. Instead of the fuel burning completely to produce carbon dioxide, it produces carbon monoxide instead.
This gas is harmful to jumans because it combines with haemoglobin in lood and takes up space that belongs to oxygen which can lead to suffocation or even death
Here we have to get the number of strontium atom needed to be laid side by side to span a distance of 2.10 mm.
9.03×10⁷ number of strontium atoms are needed to cover the distance of 2.10mm.
The radius of the strontium atom is 215 pm, thus the diameter of strontium atom is (2×215) = 430 pm.
Now we know 1 pm is equivalent to 10⁻⁹ mm. Thus 430 pm is equivalent to (430×10⁻⁹) = 4.3×10⁻⁷ mm.
Thus 1 strontium atom can occupy 4.3×10⁻⁷mm of space. Now the distance to be occupied by the lay down of the strontium atom side by side of the span is 2.10 mm.
Hence,
×10⁷ = 9.03×10⁷ number of atoms are needed.