Answer:
2.765amu is the contribution of the X-19 isotope to the weighted average
Explanation:
The average molar mass is defined as the sum of the molar mass of each isotope times its abundance. For the unknown element X that has 2 isotopes the weighted average is defined as:
X = Mass X-19 * Abundance X-19 + MassX-21 * Abundance X-21
The contribution of the X-19 isotope is its mass (19.00 amu) times its abundance (14.55% = 0.1455). That is:
19.00amu * 0.1455 =
2.765amu is the contribution of the X-19 isotope to the weighted average
Answer: 11.5 moles of carbon
Explanation:
Based on Avogadro's law:
1 mole of any substance has 6.02 x 10^23 atoms
So, 1 mole of carbon = 6.02 x 10^23 atoms
Z moles = 6.93 x 10^24 atoms
To get the value of Z, cross multiply:
(6.93 x 10^24 atoms x 1mole) = (6.02 x 10^23 atoms x Z moles)
6.93 x 10^24 = (6.02 x 10^23 x Z)
Z = (6.93 x 10^24) ➗ (6.02 x 10^23)
Z = 1.15 x 10
Z = 11.5 moles
Thus, there are 11.5 moles of carbon.
I think the answer is C. An element or compound that cannot be physically separated. Sorry if im wrong.
Ethanol is: flammable, liquid at room temperature, the boiling point is 78.37 ° C.
Answer: The total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.
Explanation:
Given: Mass = 46 g
Initial temperature = 
Final temperature = 
Specific heat capacity of ice = 2.05 
Formula used to calculate the energy is as follows.
where,
q = heat energy
m = mass
C = specific heat capacity
= initial temperature
= final temperature
Substitute the values into above formula as follows.
Thus, we can conclude that the total energy, in kilojoules, that is needed to turn a 46 g block of ice at -25 degrees C into water vapor at 100 degrees C is 11.787 kJ.
