Energy is required to melt a solid because the cohesive bonds between the molecules in the solid must be broken apart so that the molecules can move around at comparable kinetic energies
Answer:
104.969 amu.
Explanation:
From the question given above, the following data were obtained:
Isotope A:
Mass of A = 107.977 amu
Abundance (A%) = 0.1620%
Isotope B:
Mass of B = 106.976 amu
Abundance (B%) = 1.568%
Isotope C:
Mass of C = 105.974 amu
Abundance (C%) = 47.14%
Isotope D:
Mass of D = 103.973 amu
Abundance (D%) = 51.13%
Average atomic mass =?
The average atomic mass of the element can be obtained as follow:
Average atomic mass = [(Mass of A × A%) /100] + [(Mass of B × B%) /100] + [(Mass of C × C%) /100] + [(Mass of D × D%) /100]
Average atomic mass = [(107.977 × 0.1620)/100] + [(106.976 × 1.568)/100] + [(105.974 × 47.14)/100] + [(103.973 × 51.13)/100]
= 0.175 + 1.677 + 49.956 + 53.161
= 104.969 amu
Therefore, the average atomic mass of the element is 104.969 amu.
The missing part of the question is shown in the image attached
Answer:
C10H22(l) + 31/2 O2 (g)-----> 10CO2(g) + 11H2O(l)
V= 70.4L of CO2
Explanation:
Equation of the reaction is:
C10H22(l) + 31/2 O2 (g)-----> 10CO2(g) + 11H2O(l)
Number of moles of decane = mass/ molar mass
Molar mass of decane= 122gmol-1
n= 0.370×10^3g/122gmol-1= 3.0 moles
T= 13°C +273=286K
P= 1atm
R= 0.082 atmLK-1mol-1
From :
PV= nRT
V= nRT/P
V= 3.0×0.082×286/1
V= 70.4L of CO2
Activation Energy. All chemical reactions, even exothermic reactions, need a certain amount of energy to get started. This energy is called activation energy. For example, activation energy is needed to start a car.
The correct answer choice from the statement above about investigated factors from lab results is :
Students who spend less time studying after school get lower math grade
Option D is the correct answer
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So therefore, The correct answer choice from the statement above about investigated factors from lab results is :
Students who spend less time studying after school get lower math grade
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