Answer:
70 amu
Explanation:
The average atomic mass of an element is calculated by first finding the products of the atomic masses of the isotopes of that element and their respective percent abundances. The second/last step is finding the sum of those products, applying significant figures rules throughout. In this case, you would do the following:
(69 x 60%) + (71 x 40%) = 70 amu (with significant figures rules applied)
Cheers
Nitrogenous base. These are Adenine (A), Glycine (G), Thymine (T) or Uracil (U), and Cytosine (C).
A always pairs T (or U in RNA)
G always pairs with C
Hope I helped! xx
Pneumonoultramicroscopicsilicovolcanoconiosis
Answer:
167 kJ
Explanation:
Given parameters
Change in enthalpy = 130 kJ (decrease)
Work done = -137 kJ
Change in energy, \delta = ?
From the first law of thermodynamics:
ΔH = ΔE + PΔV,
Where, ΔH= change in enthalpy
ΔE = change in Internal energy
Substituting values into the above formula —
130 kJ = ΔE + -137 kJ
130 kJ = ΔE - 137 kJ
therefore,
ΔE = (130 + 137 ) kJ
ΔE = 167 kJ
Therefore, the change in energy of the gas mixture during the reaction is 167 kJ.
Since the value of energy change Is positive, therefore this Is endothermic reaction
Answer:
See explanation below
Explanation:
First, you are not providing any data to solve this, so I'm gonna use some that I used a few days ago in the same question. Then, you can go and replace the data you have with the procedure here
The concentration of liquid sodium will be 8.5 MJ of energy, and I will assume that the temperature will not be increased more than 15 °C.
The expression to calculate the amount of energy is:
Q = m * cp * dT
Where: m: moles needed
cp: specific heat of the substance. The cp of liquid sodium reported is 30.8 J/ K mole
Replacing all the data in the above formula, and solving for m we have:
m = Q / cp * dT
dT is the increase of temperature. so 15 ° C is the same change for 15 K.
We also need to know that 1 MJ is 1x10^6 J,
so replacing all data:
m = 8.5 * 1x10^6 J / 30.8 J/K mole * 15 m = 18,398.27 moles
The molar mass of sodium is 22.95 g/mol so the mass is:
mass = 18,398.27 * 22.95 = 422,240.26 g or simply 422 kg rounded.
