Explanation:
The given data is as follows.
Refractive index of mixture = 1.456
Refractive index of hexane = 1.375
Refractive index of toulene = 1.497
Let mole fraction of hexane = 
and, mole fraction of toulene = 
Also, 
or, 
Hence, calculate the mole fraction of hexane as follows.
refractive index mixture= mole fraction hexane × ref index hexane + mole fraction toluene × ref index toluene.
1.456 = 
1.456 = 
0.081 = 
= 
= 0.66
Since,
= 1 - 0.66
= 0.34
Thus, we can conclude that mole fraction of hexane in your sample is 0.34.
Answer:
In 4 years the carbon monoxide level reach 7.8 parts per million.
Explanation:
The average daily level of carbon monoxide in the air is given by :
parts per million..[1]
The population of the region after t years is modeled by the formula :
...[2]
If level of carbon monoxide level reach 7.8 parts per million in t years.
Using [1] to calculate value of x.
c(x)= 7.8 parts per million
c(x) = 0.5x + 2 parts per million
7.8 parts per million = (0.5x + 2 ) parts per million
Solving for x , we get ;
x = 11.6
Using [2] to calculate value of t.:
x(t) = 11.6
Solving for 't' we get ;
t = 4 years
In 4 years the carbon monoxide level reach 7.8 parts per million.
Answer: Hematocrit and WBC counts increases.
Explanation:
The hematocrit, also known as the "Hct", "crit" or PCV (packed cell volume) determines the percentage of red blood cells in the plasma. The term hematocrit means "to separate blood."
A patient with a severe burn loses huge amounts of plasma from damaged capillaries. As a result, the vascular space loses fluid in relation to cellular elements and the patient's hematocrit will be significantly increased.
Answer:
D. 4.281 x 10⁻¹⁹ Joules.
Explanation:
- To get the change in energy, we can use the relation:
<em>E = (hc)/λ</em>
where,
E is the energy of the atom.
h is Planck’s constant = 6.626 x 10⁻³⁴ J.s.
c is the speed of light = 2.998 x 10⁸ m/s.
λ is the wavelength of photon = 4.64 x 10⁻⁷ m.
<em>∴ E = (hc)/λ</em> = (6.626 x 10⁻³⁴ J.s)(2.998 x 10⁸ m/s)/(4.64 x 10⁻⁷ m) = <em>4.281 x 10⁻¹⁹ J.</em>
Answer:
7. A) I, II
; 8. D) 2.34e9 kJ
Step-by-step explanation:
7. Combustion of ethanol
I. The negative sign for ΔH shows that the reaction is exothermic.
II. The enthalpy change would be different if gaseous water were produced.
That's because it takes energy to convert liquid water to gaseous water, and this energy is included in the value of ΔH.
III. The reaction is a redox reaction, because
- Oxygen is reacting with a compound
- The oxidation number of C increases
- The oxidation number of O decreases.
IV. The products of the reaction occupy a smaller volume than the reactants, because 3 mol of gaseous reactant are forming 2 mol of gaseous product.
Therefore, only I and II are correct.
7. Hindenburg
Data:
V = 2.00 × 10⁸ L
p = 1.00 atm
T = 25.1 °C
ΔH = -286 kJ·mol⁻¹
Calculations:
(a) Convert temperature to kelvins
T = (25.1 + 273.15) K = 298.25 K
(b) Moles of hydrogen
Use the <em>Ideal Gas Law</em>:
pV = nRT
n = (pV)/(RT)
n = (1.00 × 2.00 × 10⁸)/(0.082 06 × 298.25) = 8.172 × 10⁶ mol
(c) Heat evolved
q = nΔH = 8.172 × 10⁶ × (-286) = -2.34 × 10⁹ kJ
The hydrogen in the Hindenburg released 2.34e9 kJ
.
