Earth's atmosphere has mainly five layers as
exosphere, thermosphere, mesosphere, stratosphere and troposphere. The
composition of atmosphere is 78 % of N₂,
21 % of O₂, 1 % of Ar and rest
is CO₂ and trace gases.
Earth's atmosphere helps to make suitable conditions for living things by<span>
1. blocking harmful uv rays by ozone
layer
<span> 2. trapping heat to maintain the temperature on
Earth's surface</span>
3. having O₂ gas for breathing of living things</span><span>
4. having CO₂ gas which is used to make foods by
photosynthesis</span><span>
<span> 5. creating pressure on Earth's
surface to keep water in its liquid form.</span></span>
Answer:
168°C is the melting point of your impure sample.
Explanation:
Melting point of pure camphor= T =179°C
Melting point of sample =
= ?
Depression in freezing point = ![\Delta T_f](https://tex.z-dn.net/?f=%5CDelta%20T_f)
Depression in freezing point is also given by formula:
![\Delta T_f=i\times K_f\times m](https://tex.z-dn.net/?f=%5CDelta%20T_f%3Di%5Ctimes%20K_f%5Ctimes%20m)
= The freezing point depression constant
m = molality of the sample = 0.275 mol/kg
i = van't Hoff factor
We have:
= 40°C kg/mol
i = 1 ( non electrolyte)
![\Delta T_f=1\times 40^oC kg/mol\times 0.275 mol/kg](https://tex.z-dn.net/?f=%5CDelta%20T_f%3D1%5Ctimes%2040%5EoC%20kg%2Fmol%5Ctimes%200.275%20mol%2Fkg)
![\Delta T_f=11^oC](https://tex.z-dn.net/?f=%5CDelta%20T_f%3D11%5EoC)
![\Delta T_f=T- T_f](https://tex.z-dn.net/?f=%5CDelta%20T_f%3DT-%20T_f)
![T_f=T- \Delta T_f=179^oC-11^oC=168^oC](https://tex.z-dn.net/?f=T_f%3DT-%20%5CDelta%20T_f%3D179%5EoC-11%5EoC%3D168%5EoC)
168°C is the melting point of your impure sample.
Answer:
17.04%
Explanation:
Actual Value = 173.1
Measured Value = 143.6
Percent error is obtained using the equation;
Percent error = (Measured - Actual) / Actual ]* 100
Percent error = [ (143.6 - 173.1) / 173.1 ] * 100
The absolute value of (Measured - Actual) is taken,
Percent Error = [29.5 / 173.1 ] * 100
Percent Error = 0.1704 * 100 = 17.04%