Answer:
Therefore the theoretical density of iron is 7.877 g/cm³ .
Therefore the number of vacancy per cm³ is
Explanation:
This question is incomplete, the complete question is;
Tonksite is a solid at 300.00K. At 300.00 K its enthalpy of sublimation is 66.00 kJ/mol. The sublimation pressure at 300.00 K is 5.00 × 10⁻⁴ atm
Calculate the sublimation pressure of the solid at the melting point of 400.00 K assuming that the enthalpy of sublimation is not a function of temperature.
Answer: the sublimation pressure of the solid at the melting point is 0.3727 atm
Explanation:
Given that;
T1 = 300 K
T2 = 400 K
H_sub = 66 kJ/mol = 66000 J/mol
P1 = 5.00 × 10⁻⁴ atm
p2 = ?
now using the expression
log( p2 / 5.00 × 10⁻⁴ ) = (H_sub / R × 2.303 ) (( T2 - T1) / T1T2)
now we substitute of given values into the expression
log(p2/p1) = (66000 / 8.314 × 2.303 ) (( 400 - 300) / 300 × 400 )
p2 = 0.3727 atm
therefore the sublimation pressure of the solid at the melting point is 0.3727 atm
Answer:
b. 17,190
Explanation:
Using the formula for C-14 dating,
where Present Value N =1/8 of Parent Sample
Initial Value, 
=1
Half Life, 
=5730 years
=17,190
Therefore the fossil is about 17190 years old.
<h3>
Answer: Si (choice D)</h3>
This is the element Silicon.
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Explanation:
First convert each percentage to its decimal form.
For example, 92.2297% converts to 0.922297 after moving the decimal point two spots to the left.
After doing that, multiply those decimal values with their respective atomic mass unit (amu) values.
- 27.9769 * 0.922297 = 25.8030109393
- 28.9765 * 0.046832 = 1.357027448
- 29.9738 * 0.030872 = 0.9253511536
Then we add up the results
25.8030109393 + 1.357027448 + 0.9253511536 = 28.0853895409
That rounds to about 28.085
Then look at the periodic table to see the atomic mass of Cobalt (Co), Aluminum (Al), Nickel (Ni) and Silicon (Si). The mass values listed in the periodic table are weighted averages of all the isotopes. The units for the mass are still in amu.
- Cobalt = 58.933
- Aluminum = 26.982
- Nickel = 58.693
- Silicon = 28.085
We have a match with silicon, showing that <u>choice D</u> is the final answer.
