Answer:
ΔH = 2.68kJ/mol
Explanation:
The ΔH of dissolution of a reaction is defined as the heat produced per mole of reaction. We have 3.15 moles of the solid, to find the heat produced we need to use the equation:
q = m*S*ΔT
<em>Where q is heat of reaction in J,</em>
<em>m is the mass of the solution in g,</em>
<em>S is specific heat of the solution = 4.184J/g°C</em>
<em>ΔT is change in temperature = 11.21°C</em>
The mass of the solution is obtained from the volume and the density as follows:
150.0mL * (1.20g/mL) = 180.0g
Replacing:
q = 180.0g*4.184J/g°C*11.21°C
q = 8442J
q = 8.44kJ when 3.15 moles of the solid react.
The ΔH of the reaction is:
8.44kJ/3.15 mol
= 2.68kJ/mol
An igneous rock is defined by how the rock is formed; igneous rocks are formed by the solidification of molten rock materials. Examples of igneous rocks include Diorite, Gabbro, Granite, Pegmatite.
Answer:
f = 1.87 × 10¹⁹ s⁻¹
Explanation:
Given data:
Wavelength of light = 1.6 ×10⁻¹¹ m
Frequency of light = ?
Solution:
Formula:
speed of light = wavelength × frequency
Frequency = speed of light / wavelength
speed of light = 3× 10⁸ m/s
Now we will put the values in formula:
Frequency = speed of light / wavelength
f = 3× 10⁸ m/s / 1.6 ×10⁻¹¹ m
f = 1.87 × 10¹⁹ s⁻¹
The half life of 131 i is 8.06 days
calculation
by use of concentration time equation for radioactive decay
In Nt/No = -Kt
where Nt/No is the fraction of the sample remaining at time T
convert 50.2% in decimal = 50.2/100 = 0.502
therefore = In 0.502 = - K 8.0 t
- 0.689 =-8.0 k
divide both side by 8.0
K = 0.860
t1/2 = 0.693/K
t1/2 = 0.693/0.860 = 8.06 days
