Answer:
Moles=2.04×10^(-6)
Explanation:
No. Of moles=no. Of particles/ Avogadro's no
(Where no. Of particles may be atoms molecules or compounds)
Moles=1.23×10^18/6.022×10^23
Moles=0.204×10^(-5)
Moles=2.04×10^(-6)
Answer: d) -705.55 kJ
Explanation:
Heat of reaction is the change of enthalpy during a chemical reaction with all substances in their standard states.

Reversing the reaction, changes the sign of 


On multiplying the reaction by
, enthalpy gets half:


Thus the enthalpy change for the given reaction is -705.55kJ
Answer:
The solution is given below.
Explanation:
Speed = Distance(m)/Time(sec.)
Distance traveled = 150 m
Time taken = 3.5 seconds
Speed of car = 150/3.5 = 42.86 m/s
So the car traveled at a speed of 42.86 m/s.