Answer:
The temperature difference of the body after 3 hours = 5.16 K
Explanation:
we know that the number of moles of O₂ inhaled are 0.02 mole/min⁻¹
or, 1.2 mole.h⁻¹
The average heat evolved by the oxidation of foodstuffs is then:
⇒ Q avg =
= 7.2 kj.h⁻¹.Kg⁻¹
the heat produced after 3 h would be:
= 7.2 kj. h⁻¹.Kg⁻¹ x 3 h
= 21.6 kj. kg⁻¹
= 21.6 x 10³ j kg⁻¹
We know Qp = Cp x ΔT
Assume the heat capacity of the body is 4.18 J g⁻¹K⁻¹
⇒ ΔT = 
⇒ ΔT = 
⇒ ΔT = 5.16 K
Answer:
The average atomic mass of bromine is 79.9 amu.
Explanation:
Given data:
Percentage of Br⁷⁹ = 55%
Percentage of Br⁸¹ = 45%
Average atomic mass of bromine = ?
Formula:
Average atomic mass = [mass of isotope× its abundance] + [mass of isotope× its abundance] +...[ ] / 100
Now we will put the values in formula.
Average atomic mass = [55 × 79] + [81 ×45] / 100
Average atomic mass = 4345 + 3645 / 100
Average atomic mass = 7990 / 100
Average atomic mass = 79.9 amu
The average atomic mass of bromine is 79.9 amu.
The Law states that the change in internal energy (U) of the system is equal to the sum of the heat supplied to the system (q) and the work done ON the system (W)
<span>ΔU = q + W </span>
<span>For the first question, 0.653kJ of heat energy is removed from the system (balloon) while 386J of work is done ON the balloon, thus </span>
<span>ΔU = -653J + 386J </span>
<span>=-267J </span>
<span>Thus internal energy decrease by 267J </span>
<span>For the second question, 322J of heat energy is added to the system (gold bar) while no work is done on the gold bar, this is an isochoric/isovolumetric process, thus </span>
<span>ΔU = 322J + 0 </span>
<span>=322J </span>
<span>Thus internal energy increase by 322J</span>
The answer is:
a)0.25%
b) metallic bond
The explanation:
A) The percentage of ionic character in a compound having some covalent character can be calculated by the following equation. The percent ionic character = Observed dipole moment/Calculated dipole moment assuming 100% ionic bond × 100.
-The percent ionic character is a function of the electron negativities of the ions XA and XB . The electronegativities for Al and Mn are 1.5 and 1.6, respectively
:
when %IC = [1-exp(-1/4) (XB-XA)^2].100
so, %IC = [1 - exp(- 0.25)(1.6- 1.5)^2] . 100 = 0.25%
(b) Because the percent ionic character is so small (0.25%) and this intermetallic compound is composed of two metals Al and Mn, the bonding is completely metallic.
Metallic bond:
• Metallic bonding can be either weak (68 kJ/mole or 0.7 eV/atom for Hg) or strong (850 kJ/mole or 8.8 eV/atom for W)
• Metallic bonding gives rise to high electrical and thermal conductivity.
-The electrons are loosely held since each atom has several unoccupied valence orbitals; it is relatively easy for the electrons to move about. In this manner the electrons allow atoms to slide past each other.
