What occurs during this change?
(1) Energy is absorbed and a bond is formed.
(2) Energy is absorbed and a bond is broken.
(3) Energy is released and a bond is formed.
(4) Energy is released and a bond is broken.
Answer is: (2) Energy is absorbed and a bond is broken.
This energy is called bond-dissociation energy.
Bond-dissociation energy is the measure of bond strength in a chemical bond.
Bond energy of bromine molecule (sigma bond) is energy needed for breaking up one molecule of bromine into two bromine atoms.
When two bromine atoms (Br) form molecule of bromine (Br₂), than energy is released and bond is formed.
(2) 15 mL of HCl(aq) at 20.°C
(3) 10. mL of H2O(l) at 35°C
(4) 15 mL of H2O(l) at 30.°C
Answer: The correct answer is option 3.
Explanation: Average kinetic energy is defined as the energy of motion of the particles of a system. It is a measure of Kelvin Temperature.
Mathematically,
where,
K = kinetic energy of the molecules measured in joules.
R = Gas constant =
= Avogadro's number =
T = Temperature in kelvins.
Kinetic energy is directly proportional to the temperature of the system.
More the temperature, more will be the kinetic energy of the molecules.
Hence, the correct answer is Option 3.
The balanced reaction is:
Mg (s) + 2HCl (aq) = H2 (g) + MgCl2 (aq)We are given the amount of reactants to be reacted. This will be the starting point of the calculations.
.125 L HCl solution (6.0 mol HCl / L solution) ( 1 mol H2 / 2 mol HCl ) ( 2.02 g H2 / 1 mol H2 ) = 0.76 g H2
B. magnesium and oxygen
C. magnesium and magnesium