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
PH=-log[H⁺]
pH=-log(1.87×10⁻¹³)
pH=12.72
I hope this helps. Let me know if anything is unclear.
Answer:The Upper Paleolithic period started about 40,000 years BC and ended about 10,000 years BC. So it took place between 40,000 and 10,000 BC. After that started the Mesolithic Era ( 10,000 to 4,000 BC ). Stone tools in the Upper Paleolithic period were primarly blade-based technology. Also this period is well known for the cave art and paintings of animals. Answer: C ) The period took place between 40,000 and 4,000 BC ( not true ).
Explanation:
Answer:
The metals that would be able to reduce copper ions in solution would be hydrogen, lead, tin, nickel, iron, zinc, aluminum, magnesium, sodium, calcium, potassium, silver, gold, copper and lithium 5.
Explanation:
Answer:
a)


b)
Sulphurdioxide
c)


d)
Incomplete combustion produce harmful gases.
Explanation:
a)
Carbon reacts with atmospheric oxygen to form carbondioxide as well as sulphur dioxide.
The chemical equations are as follows.


b)
Sulfur dioxide is very harmful to the environment to cause acid rains.
This harmful gas mix with rain water to form sulphuric acid.
c)
The balanced chemical equation for the reaction that produces harmful environmental effects is as follows.



d)
In the absence of proper amount of oxygen required for combustion, incomplete combustion will take place which will result in formation of more carbondioxide an other harmful gases.