Answer:
c)
Explanation:
The reaction between ethene and HBr is:
CH2=CH2 + HBr → CH3CH2Br
Thus, the double bond C=C and the bond H-Br were broken, and the bonds C-C, C-H and C-Br were formed. The enthalpy of the reaction (the energy change), is the sum of the enthalpies of the reactions that were broken with the bonds that were created.
To break a bond, it's necessary to the molecule to gain energy, thus the process is endothermic and H>0, and to form a bond, it's necessary to release energy, and so H<0, so:
ΔH = ∑n*Hbroken - ∑n*Hformed, where n is the coefficient of the substance, so:
ΔH = (612 + 366) - (348+412+276)
ΔH = -58 kJ/mol
The minus signal indicates that the energy was released.
Chemical, if it gives off a reaction like that its chemical
Answer: The given statement is true.
Explanation:
It is known that due to increase in temperature ice melts. Therefore, during ice age there is also melting of ice and solid state of water changes into liquid state of water.
Therefore, this water moves from its initial place and changes its position result in the change of land and specific areas.
Thus, we can conclude that the statement during an ice age, land can move and specific areas can be permanently changed is true.