air that is cooling will cause the highest pressure
Explanation:
This is because heat has to escape a certain area and if the heat can't escape then more and more pressure will build up in a area.
Answer:
MOLAR MASS = 32 g/mol
Explanation:
Condition of standard temperature and pressure(STP) are as follow:
Temperature = 273 K
Pressure = 1 atm (or 100000 Pa)
Here atm is atmosphere and Pa is Pascal
STP conditions arte used for measuring gas density and volume using Ideal Gas Law.Here 1 mole of ideal gas occupies 22.4 L of volume.
According toi Ideal Gas Equation :
PV = nRT
where P = pressure, n= number of moles, V = volume ,R= Ideal Gas Constant and T= temperature
From question:
V=280 ml = 0.28 L
P = 1 atm
R=0.08205 L atm/K mol
T=273 K
Putting values in above formula :
n = 0.0125 moles
Now
given mass = 0.4 g (given)
On solving we get:
Molar mass = 32 g/mol
The volume of gas under STP is 0.512 liters.
<u>Explanation:</u>
At STP (Standaed Temperature and Pressure)
T = 0°C
P = 1 atm = 760 mmHg
Given
P1 = 756 mmHg
T1 = -21.5°C = -21.5 + 273 = 251.5 K
V1 = 475 mL = 0.475 L
P2 = 760 mmHg
T1 = 0°C = 0 + 273 = 273 K
We know that
V2 = 0.512 L
Answer:
a. Endothermic
b. 26.37kJ/mol
Explanation:
a. As we can see, the temperature of the water is decreasing when the reaction is occurring, that means the reaction is absorbing heat and is endothermic
b. To find the enthalpy we must find the change in heat when 12.1g of KCl are dissolved. Using the equation:
Q = -m*ΔT*C
<em>Where Q is change in heat</em>
<em>m the mass of solution (250g + 12.1g = 262.1g)</em>
<em>ΔT is change in heat (17.1°C - 21.0°C = -3.9°C)</em>
<em>And C is specific heat of the solution (4.184J/g°C assuming is the same than the specific heat of water).</em>
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Replacing:
Q = -262.1g*-3.9°C*4.184J/g°C
Q = 4277J = 4.28kJ
As reaction enthalpy is the change in heat per mole of reaction, we must find the moles of 12.1g of KCl:
<em>Moles KCl -Molar mass: 74.55g/mol-:</em>
12.1g KCl * (1 mol / 74.55g) = 0.1623 moles KCl
The reaction enthalpy us:
4.28kJ / 0.1623mol = }
<h3>26.37kJ/mol</h3>
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